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Example force plate properties for triggered sync.This page provides instructions on integrating an AMTI Force plate system with an OptiTrack motion capture system.
When a motion capture system is used in conjunction with force plates, they work together as an efficient tool for various research applications including biomechanical analysis, clinical gait analysis, physiology research, sports performance research, and many more. An OptiTrack motion capture system can synchronize with force plates to obtain both kinematic and kinetic measurements. Note that force plate integration is supported only with a Prime camera system using the eSync 2 synchronization hub. This page provides quick guidelines for setting up and configuring force plates — with digital outputs — along with the OptiTrack motion capture system.
For detailed information on specifications and configurations on the force plates, refer to the documentation provided by the force plate manufacturer.
Analog Platforms
Analog force plate devices can only be implemented via DAQ devices. Incoming voltage signals can be detected through the data acquisition channels, but force plate related software features (vectors, position calibration, etc.) will not be supported in Motive for the analog platforms. Refer to the NI-DAQ Setup page for detailed instructions on integrating analog devices.
Motive 3.0 Update
Starting from Motive 3.0, reference clock synchronization while in Live mode is supported.
Supported Amplifier Models: AMTI Gen 5, AMTI Optima.
Force platforms that are compatible with the above amplifier models.
Prime series Ethernet camera system with the eSync synchronization hub.
Motive 1.9 or above.
AMTI Force Plate System Setup
Connect each force plate into the host PC. For force plate systems with external amplifiers, the platform must be connected to the amplifier which uplinks to the host computer. For detailed instructions on setting up the Force Plate system with a host PC, refer to the AMTI documentation.
Camera System Setup
Setup the OptiTrack camera system and place the force plate(s) at the desired location(s); ideally, near the center of the volume. See Quick Start Guide or Hardware Setup page for details.
Wiring the eSync with the Gen 5 Amplifier
For accurate synchronizations, the eSync 2 synchronization hub must be used. The eSync 2 has signal output ports that are used to send out synchronization signals to child devices. Connect the BNC output ports of the eSync to sync input ports (Genlock/Trigger Input) of force plate amplifiers.If force plate systems have RCA sync ports, use RCA cables along with the 50 Ohm BNC Male to 75 Ohm RCA Jack Adapters included with the eSync 2 to connect the amplifiers. The above wiring diagram shows how force plate systems need to be connected to an Ethernet camera system through the eSync 2.
Multiple Devices Sync
There are total four output ports on the eSync 2, and multiple force plates and external devices can be integrated if needed. Consult our Engineers for multiple force plate synchronizations.
Hot Plugging
Hot plugging is not supported with the integration. When a new device is connected to the system, you must re-start Motive to instantiate it.
Before setting up the force plates in Motive, make sure software components required by the force plate system is installed on the computer. AMTI's software (e.g. AMTINetForce) must be able to detect and initialize the connected devices in order for the force plates to be properly initialized and used in Motive. Once this has been confirmed working, start setting up Motive. Please refer to manufacturer documentation for more information.
In order to integrate force plate systems with Motive, you will need to setup the required drivers and plugins. Motive installer is packaged with the Peripheral Device module which can be added. During the Motive installation, a list of program features will be shown in the Custom Setup section. Here, change the setting for the Peripheral Device module, as shown in the below image, so that the module is installed along with Motive Files.
Note : Even if you are not using NI-DAQ, it is still necessary to install NI-DAQmx drivers that come up next in the installer.
1. Start Motive
If the hardware and software for the force plates are configured and successfully recognized, Motive will list out the detected force plates with number labels (1, 2, etc..). Motive will notify you of incorrect or nonexistent force plate calibration files. When the devices are successfully instantiated in Motive, the Log pane will indicate that the device has been created and loaded.
2. Calibrate Cameras
Calibrate the capture volume as normal to get the orientation of the cameras (see the Quick Start Guide or Calibration page for more information). The position of the force plate is about the center of the volume, and when you recalibrate or reset the ground plane, you will need to also realign the position of your force plates for best results.
3. Setup CS-400
On the CS-400 calibration square, pull the force plate alignment tabs out and put the force plate leveling jigs at the bottom. The leveling jigs align the calibration square to the surface of your force plate. The alignment tabs allow you to put the CS-400 flush against the sides of your force plate giving the most accurate alignment.
4. Place CS-400 on force plate
Place the calibration wand on the force plate so that vertex of the wand is located at the right-hand corner of the side where the cable input is located (as shown in the image below). A correct placement of the calibration square is important because it determines the orientation of the force plate and its local coordinate axis within the global system. The coordinate systems for force plates are independent of the system used Motive.
AMTI Force Plates
AMTI force plates use the right-hand system. The long arm of CS-400 will define the Y axis, and the short arm will define the X axis of the force plate. Accordingly, Z axis is directed downwards for measuring the vertical force.
5. Set force plate position in Motive.
After placing the calibration square on the force plate, select the CS-400 markers in Motive. Right click on the force plate you want to locate, and click Set Position. When there are multiple force plates in a volume, you may need to step on the force plate to find which platform the calibration square is on. In Motive, uncalibrated force plates will light up in green and a force vector will appear when you step on the plate. Repeat step 4 and 5 for other force plates as necessary.
Referencing to the markers on the calibration square, Motive defines the location of the force plate coordinate system within the global coordinate system.
Motive uses manufacturer defined X, Y, and Z mechanical-to-electrical center offset when calculating the force vector and the center of pressure. For digital based plates, this information is available from the SDK and also stored in the plate's on-board calibration data.
6. Zero force plates.
After you have calibrated each of your force plates, remove the CS-400 from the volume. Right click one of your force plates in Motive and click Zero (all). This will tare the scale and set the current force on the plate data to 0. This will account for a small constant amount of measurement offset from the force plate. Remember that it zeros all of the force plates at once. So make sure there are no objects on any of the force plates.
7. Set sampling rate
Sampling rate of force plates is configured through the synchronization setup which will be covered in the following section. You can sync the force plates either through the reference clock sync or through the triggered sync. Please note that only specific sampling rates may be supported depending on the amplifier models.
Supported force plate sampling rates:
For AMTI force plates support the following sampling rates depending on the amplifier used. For the most up-to-date information, consult their documentation. The supported sampling rates (Hz) are the following:
AMTI Gen 5 Amplifier: 2000, 1800, 1500, 1200, 1000, 900, 800, 600, 500, 450, 400, 360, 300, etc...
AMTI Optima Amplifier: 1000, 600, 500, 300, 250, 200, 150, 125, 120, 100, 60, 50, 30, 25, 15, 10.
There are two synchronization approaches you could take: Synchronization through clock signal or through recording trigger signal.
Synchronization via clock signal utilizes the internal clock signal of the eSync to synchronize the sampling of the force plates on per-frame basis. However, when there is another device (e.g. NI-DAQ) being synchronized to the clock signal frequency, the sampling rate cannot be set for each individual device. In that case, triggered sync must be used for synchronizing the initial recording trigger. Synchronization via trigger signal utilizes the recording trigger in Motive to align the initial samples from both systems. After the initial sync, both systems run freely at their own sampling rate. If the force plates are running at whole multiples of the camera system, the collected samples will be aligned. However, since the sampling clocks are not perfectly accurate, alignment of the samples may slowly drift over time. Thus, when synchronizing via recording trigger, it is better to keep the record times short.
When synchronizing through the eSync, use the following steps to configure the sync settings in Motive. This will allow both systems to be triggered simultaneously with reference to the parent synchronization device, the eSync.
Reference Clock Sync Setup Steps
Open the Devices pane and the Properties pane.
In the Devices pane, select the eSync among the listed devices. This will list out the synchronization settings in the properties pane for the selected eSync.
In the Properties pane, under Sync Input Settings section, set the Source to Internal Clock.
Next, to the Clock Frequency section, input the sampling rate that you wish the run the force plates in. This clock signal will be eventually outputted to the force plate system to control the sampling rate. For this guide, let's set this to 1200 Hz.
Once the clock frequency is set, apply the Input Divider/Multiplier to the clock frequency to set the framerate of the camera system. For example, if you set the Input Divider to 10 and the Input Multiplier to 2 with internal clock frequency running at 1200 Hz, the camera system will be running at 240 FPS. The resulting frame rate of the camera system will be displayed in the Camera Rate section.
Next step is to configure the output signal so that the clock signal can be sent to the force plate system. Under the Outputs section, enable the corresponding output port of the eSync which the force plate system is connected to.
Set the Output 1-4 → Type to Internal Clock.
Now that the eSync has been configured, you need to configure the force plate properties in Motive. While the force plate(s) is selected in Motive, access the Properties pane to view the force plate properties. Here, set the following properties:
Record Trigger → False
Reference Clock Sync → True
eSync Output Channel → output port used on the eSync.
Once this is set, the force plate system will start sampling at the frequency of the clock signal configured on the eSync, and this rate will be displayed on the Devices pane as well.
eSync 2 Settings Tip:
In Motive 3.0 and above, you can quickly configure eSync into biomech sync settings by right-clicking on the eSync from the Devices pane and select one of the presets from the context menu. This will enable and set all of the eSync outputs to the Internal Clock and set the clock frequency.
Live Data
Starting from Motive 3.0, clock synchronization in Live mode is supported, and the force vector visualization will be available both in Live and Edit modes.
Triggered Sync Setup Steps
Open the Devices pane and the Properties pane.
The final frame rate of the camera system will be displayed at the very top of the Devices pane.
In the Devices pane, select the eSync among the listed devices. This will list out the synchronization settings in the Properties pane for the selected eSync.
Set up the output signal so that the recording trigger signal can be sent to the force plate system. In the Outputs section, enable and configure the corresponding output port of the eSync which the force plate system is connected to.
Set the Output 1-4 → Type to Recording Gate.
Now that the eSync has been configured, you need to configure the properties of the force plates. While the force plate(s) is selected in Motive, access the Properties pane to view the force plate properties. Here, set the following properties:
Record Trigger → Device
Reference Clock Sync → False
eSync Output Channel → output port used on the eSync.
Once this is done, the force plate system will synchronize to the recording trigger signal when Motive starts collecting data, and the force plates will free-run after the initial sync trigger. You can configure the sampling rate of the force plates by modifying the Multiplier values in Devices pane to sample at a whole multiple of the camera system frame rate.
For free run sync setups, sampling rates of force plates can be set from the Devices pane, but the sampling rate of force plates must be configured to a whole multiple of the camera system's framerate. By adjusting the Rate Multiplier values in the Devices pane, sampling rates of the force plates can be modified. First, pick a frame rate of the camera system and then adjust the rate multiplier values to set force plates to the desired sampling rate.
ReSynch
When two systems are synchronized by recording trigger signals (Recording Gate or Recording Pulse), both systems are in Free Run Mode. This means that the recording of both the mocap system and the force plate system are triggered simultaneously at the same time and each system runs at its own rate.
Two systems, however, are synchronized at the recording trigger but not by per frame basis. For this reason, alignment of the mocap data and the force plate data may gradually drift from each other for longer captures. But this is not a problem since the sync chain will always be re-synchronized each time recording in Motive is triggered. Furthermore, Takes in general do not last too long for this drift to take effect on the data.
However, this could be an issue when live-streaming the data since recording is never initiated and two systems will be synchronized only when Motive first launches. To zero out the drift, the ReSynch feature can be used. Right-click on force plates from either the Devices pane or the perspective view, and select Resynch from the context menu to realign the sampling timing of both systems.
Before you start recording, you may want to validate that the camera and force plate data are in sync. There are some tests you can do to examine this.
The first method is to record dropping a retroreflective ball/marker onto the platform few times. The bouncing ball produces a sharp transition when it hits the surface of the platform, and it makes the data more obvious for validating the synchronization. Alternately, you can attach a marker on a tip of the foot and step on and off the force plate. Make sure that your toe — closest to the marker — strikes the platform first, otherwise the data will seem off even when it is not. You can then monitor the precise timing of the ball or the foot impacting the force plate and compare them between the mocap data and the force plate data.
The following is an example of validating good synchronization outcomes:
All of the configured device settings, including the calibration, get saved on Device Profile XML files. When you exit out of Motive, updated device profiles will be saved under the program data directory (C:\ProgramData\OptiTrack\Motive\DeviceProfiles), and this file gets loaded again when you restart Motive. You can have this file backed up to persist configured eSync and device settings. Also, if you wish to reset the device settings, you can remove XML files other than the default one from the folder, and Motive will load from the default settings.
Force plate data can be monitored from the Graph View pane. You will need to either use a provided Force Plate Forces layout or configure a custom graph layouts to show force plate data. To view the force plate data, make sure the corresponding force plates are selected, or selection-locked, in Motive.
If you are configuring your own force plate graph layout, make sure the desired force plate data channels (Fx, Fy, Fz, Mx, My, or Mz) are selected to be plotted. Then, when you select a force plate in Motive, and the data from the corresponding channels will be plotted on the graphs. When both reconstructed markers and force plate channels are selected, the force plot will be sub-sampled in order to be plotted along with trajectory data. For more information about how to configure graph layouts, read through the Graph View pane page.
Notes
The force and moment data reflects the coordinate system defined by the force plate manufacturer, which is typically the Z-down right-handed coordinate system. Note: This convention is independent of the global coordinate system used in Motive. Thus, the Fz components represent the vertical force. For more in-depth information, refer to the force plate specifications.
We recommend the following programs for analyzing exported data in biomechanics applications:
Motive exports tracking data and force plate data into C3D files. Exported C3D files can then be imported into a biomechanics analysis and visualization software for further processing. See the Data Export or Data Export: C3D page for more information about C3D export in Motive. Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
C3D Axes
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Force plate data and the tracking data can be exported into CSV files as well. When a Take file is exported into a CSV file. Separate CSV files will be saved for each force plate and it will contain the force, moment, and center of pressure data. Exported CSV file can be imported for analysis.
To stream tracking data along with the force plate data, open the Data Streaming Pane and check the Broadcast Frame Data, and make sure that you are not streaming over the camera network. Read more about streaming from the Data Streaming workflow page.
Motive can stream the tracking data and the force plate data into various applications — including Matlab — using NatNet Streaming protocol. Find more about NatNet streaming from the User's Guide included in the download.
Number of Force Plates
At the time of writing, there is a hard limit on the maximum number of force plate data that can be streamed out from Motive. Please note that only up to 8 force plate data can be streamed out from Motive and received by a NatNet SDK 4.0 application.
Starting from Motive version 3.0 and above, the digital integration of Delsys Trigno Avanti systems is supported. Through this integration, electromyography (EMG) measurements from the Trigno Avanti EMG sensors can be recorded in Motive along with the tracking data. This page provides instructions on how to set up the Delsys Trigno Avanti platform along with the OptiTrack motion capture system.
Required Components
Prime series Ethernet camera system
eSync synchronization hub
Motive 3.0 or above
Delsys Trigno Avanti Platform with EMG sensors
Delsys Trigger Module for synchronization
Trigno EMGworks OR Delsys SDK server package version 3.5.8 or above.
Firmware on both the Trigno base station and the sensors must be updated. If the firmware is installed, use the Software Update Tool to install the latest firmware. For more information, please refer to the manufacturer documentation.
Notes
Supported Sensors: Integration is supported for Delsys Trigno EMG systems with Trigno Avanti sensors only.
Supported Data Channels: Data channels for EMG measurements will be reported in Motive. Data channels for the inertial measurement unit (IMU) and accelerometer are not supported.
Supported Device/Channel Count: Integration supports one Trigno base station with up to 16 EMG data channels. Additional devices and/or data channels above this limit cannot be integrated due to a restriction of the Delsys SDK.
Synchronization: Synchronization with the motion capture system requires the Delsys Trigger Module and the eSync synchronization hub. Supports triggered sync only.
Delsys Trigno Control Utility software must be running prior to launching Motive.
Below are two diagrams depicting two types of Delsys hardware setups. One without a NI-DAQ device, and one with a NI-DAQ device. When setting up a configuration without a NI-DAQ device, you'll use a Delsys Trigger Module. This will only allow the option for Trigger Synchronization. If you use a NI-DAQ configuration, however, you have the option to use either Trigger and Reference Clock Synchronization. For more information about synchronization, please scroll down to the Synchronization section of this page.
Please make sure the firmwares on both the Trigno Base Station and the EMG sensors have been updated. You can check the firmware version using the Software Update Tool provided by Delsys. For more information, please refer to the user manual.
Before proceeding with integrating the EMG system into Motive, please make sure the required software for the Delsys Trigno Avanti sensor system is all set up on the host computer. This includes Trigno Control Utility software which will get along with the Trigno EMGworks or Delsys SDK Server package version 3.5.8. For the sensor to work in Motive they must first be configured and paired in the Delsys Trigno Control Utility (TCU) software.
In order to integrate Delsys EMG systems with Motive, you will need to setup the required drivers and plugins. Motive installer is packaged with the Peripheral Device module which can be added. During the Motive installation, a list of program features will be shown in the Custom Setup section. Here, change the setting for the Peripheral Device module, as shown in the below image, so that the module is installed along with Motive Files.
Note : Even if you are not using NI-DAQ, it is still necessary to install NI-DAQmx drivers that come up next in the installer.
Step 1. Launch Delsys Trigno Control Utility software
Make sure to launch the Delsys TCU software first. Make sure all of the sensors have been powered and paired in the TCU software. If the sensors are not detected here, they will not be detected in Motive.
Step 2. Start Motive
Once the sensors are detected and running in the Delsys TCU software, launch Motive. If the peripheral module is installed, Motive will attempt to connect to the Delsys system.
Step 3. Confirm connection
In Motive: If the sensor is connected, it will be reported under the Log panel and the Trigno device will be listed in the Devices pane.
In TCU: If the TCU software is connected to Motive, it will indicate that it has connected to a remote client. As shown in the image below.
Step 4. Enable data channels
Data Channels:
Channel 1-16: These are the channels used for reporting raw EMG signals.
Channel 17-32: These are the channels used for reporting RMS envelope for the corresponding EMG signal. For example, channel 17 reports RMS envelope of the EMG signals coming through channel 1, and channel 18 reports RMS envelope for channel 2.
Terminal Name
The terminal name in Motive correlates to the physical sensor ID given to a Trigno Avanti sensor in Delsys TCU.
Step 5. Enable device
Once you have enabled all of the desired data channels, enable the Trigno device from the Devices pane.
Step 8. Confirm incoming data in Graph pane
As a last step, use the Graph pane to check the EMG data coming through the enabled channels.
Graph Layout:
Synchronization of the Delsys Trigno EMG system with the motion capture system is accomplished through triggered sync. Triggered sync, in this situation, refers to the relationship between the Delsys Trigno EMG system and the motion capture system. Meaning, the motion capture system triggers the start of data sampling of the Delsys Trigno EMG system. Once triggered, both the motion capture system and the Delsys Trigno EMG system are truly aligned only during the first frame of recording then each move forward at their own individual sampling rates in an approximation of synchronization. Reference clock synchronization is more precise, however, it is not supported by Delsys systems. This is due to a limitation of the DelsysSDK. For more information regarding Deylsys SDK, please visit their SDK page here.
Triggered sync can be set up by connecting one of the eSync outputs to the Delsys Trigger Module. For triggered synchronization, one of the outputs from the eSync will need to be configured to output a Recording Gate signal, and it will need to be connected into the Start Input on the trigger module. The connect input port on the trigger module will also need to be set to detecting a rising edge using the toggle switch on the module.
Refer to the Delsys documentation for more information on setting up the triggered sync using the trigger module: https://www.delsys.com/downloads/USERSGUIDE/trigger-module.pdf
Setting up triggered sync
If not already, connect the Delsys trigger module into the Trigno base station.
Using a BNC cable, connect one of the output ports on the eSync into the Start Input of the triggered sync box.
[Motive] In Motive, select the eSync to access its properties from the Properties pane.
[Motive] Set the Type of the connected output port to Recording Gate.
[Motive] Select Trigno device to access its properties.
[Motive] Set the Triggered Sync setting to Device. Note that once Trigno is configured to the Triggered sync mode, EMG data will not be reporting until a recording is started to trigger the Delsys system.
Under Trigno device properties, you can set the following properties to perform data operations to the reported data.
Rectify Values
When enabled, all of the Raw EMG signal coming through channel 1~16 will be rectified and the absolute values of the measurements will be reported.
RMS Envelope Window
RMS is a common way to interpret EMG data. Motive performs RMS envelope calculation when reporting the data just for visualization purposes. For a complete EMG analysis, including additional data filtering for example, the Raw EMG signal should be processed through a separate data analysis software.Size of the RMS envelope can be changed by configuring the RMS Envelope Window property under Trigno device properties. This will set the number of samples used to calculate the RMS reported in Motive. Higher sample size will result in a smoother window and it needs to be adjusted based on the Trigno sampling frequency.
Noise Sample Size
Noise removal can be controlled by the Noise Sample Size property. Set this to 0 to completely disable noise removal.
Once Trigno system is detected in Motive and its channels are enabled, the reported EMG channel data will get recorded along with the motion tracking data. With the triggered sync setup explained above, motion capture system and the EMG system will be synchronized at the start of the recording and they will be running at their own sampling rates after the trigger point. Due to limitation of the triggered synchronization, it is recommended to keep the recordings relatively short.
The Delsys Trigno EMG device samples at a rate of 2000Hz natively, so oftentimes we are down sampling in Motive, and in rare cases, up sampling. We have found that sampling in Motive at a motion capture rate of 100Hz or 200Hz with a multiplier of 10 for the Delsys Trigno EMG device (making its sample rate at 1000Hz or 2000Hz respectively), has shown the best results. When running Motive at 120Hz, however, it has shown to have intermittent frame drops.
For consecutive recordings, please wait at least 5 seconds between each recording to allow the EMG system to get ready for the next recording trigger for proper sync. If not, the data may not get successfully recorded.
Captured analog signals are recorded within the Take file and they can be played back in Motive. When in Edit mode, the integrated EMG device will be shown under the Devices pane, and its Analog measurements can be plotted on the Graph pane. You will need to configure the graph layout and enable plotting of analog channels:
Graph Layout with Device Data Plots
Right-click on the graph view and set the desired layout dimensions.
On one of the graphs, right-click and under the Devices section, select the analog channels you wish to plot.
Recorded EMG channel data can be exported into C3D and CSV files along with the mocap tracking data. You can just follow the normal the tracking data export steps, and if the analog data exists in the TAK, they will also be exported.
C3D Export: Both mocap data and the analog data will be exported onto a same C3D file. Please note that all of the analog data within the exported C3D files will be logged at the same sampling frequency. If any of the devices are captured at different rates, Motive will automatically resample all of the analog devices to match the sampling rate of the fastest device. More on C3D files: https://www.c3d.org/
CSV Export: When exporting tracking data into CSV, additional CSV files will be exported separately for each Trigno device in a Take. Each of the exported CSV files will contain basic properties and settings at its header, including device information and sample counts. The voltage amplitude of each analog channel will be listed. Also, mocap frame rate to device sampling ratio is included since analog data is usually sampled at higher sampling rates.
Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Please contact us for any issues or questions that are not covered in this wiki page.
OptiTrack motion capture systems support the integration of National Instruments data acquisition (NI-DAQ) devices. Through NI-DAQ devices, signals from various analog devices (e.g. transducers or EMG sensors) can be converted into digital signals at a user-defined sampling frequency, and they can be precisely synchronized with the motion tracking data. This page provides instructions on connecting NI-DAQ devices and acquiring analog signals within Motive.
For a list of supported models, please refer to the Supported NI-DAQ Models section of this page.
For instructions specific to the NI-DAQ devices, please refer to the respective product User Guide or the NI's getting started guide.
OptiTrack motion capture system
The eSync 2 synchronization hub
Motive version 1.10 and above with a valid software license.
OptiTrack Peripheral Device module
NI-DAQ device(s): PCI or USB. See more at Supported Devices
Third party analog devices
The NI-DAQ functionalities are not supported with the use of the Motive API.
For integration of digital force plates, follow the Force Plate Setup guide. Analog platforms can be integrated through a NI-DAQ, but only raw voltage signals can be detected and the force plate features within Motive will not be supported.
Up to 32 analog channels are supported for each NI-DAQ device. If you wish to use higher channel counts, please contact us for more details.
OptiHub 2: Precise synchronization with a USB camera system is NOT supported. An Ethernet camera system with the eSync 2 synchronization hub should be used for NI-DAQ integrations. It is possible for the USB camera system to roughly synchronize to a NI-DAQ device via triggered sync, however, there will always be a variable time delay between the trigger and when the cameras start exposing. Due to this variable offset, the two of the recorded datasets cannot be perfectly aligned at the start of recording.
Motive supports PCI and USB data acquisition devices from National Instruments, and the NI-DAQmx driver must be installed on the computer in order to use the devices. The driver setup instructions will be covered in the software setup section of this page. A list of supported models can be found in the section below.
For general instructions on setting up the mocap system, refer to the Hardware Setup pages.
Hot plugging is not supported with the integration. When a new device is connected to the system, you must re-start Motive to instantiate it.
Below is the list of NI-DAQ device models that are supported with Motive. For best compatibility, use the recommended models or verified models since they are most tested to work with Motive. Unverified models are expected to work as well, but their integration has not been tested yet.
USB-63XX X-Series
Verified Devices
USB-6341, USB-6351, USB-6361
USB-6002
USB 6281 (M Series)
(Low Cost) USB Basic Series
NI 6000, NI 6001, NI 6002, NI 6003, NI 6008, NI 6009
E Series
NI 6023E, NI 6024E*, NI 6025E, NI 6030E, NI 6031E, NI 6032E/33E/34E/35E, NI 6036E*, NI 6040E, NI 6052E, NI 6062E*, NI 6070E, NI 6071E, NI PCI-MIO-16E-1, NI PCI-MIO-16E-4, NI PCI-MIO-16XE-10, NI PCI-MIO-16XE-50
M Series
NI 6210/11/12/15/16/18, NI 6220, NI 6221, NI 6224, NI 6225, NI 6229, NI 6230/32/33/36/38/39, NI 6250, NI 6251, NI 6254, NI 6255, NI 6259, NI 6280, NI 6281, NI 6284, NI 6289
X Series
NI 6320, NI 6321, NI 6323, NI 6341, NI 6343, NI 6345, NI 6351, NI 6353, NI 6355, NI 6356, NI 6358, NI 6361, NI 6363, NI 6365NI 6366, NI 6368, NI 6375
S Series
Simultaneous Sampling: NI 6110, NI 6111, NI 6115, NI 6120, NI 6122, NI 6123, NI 6124, NI 6132, NI 6133, NI 6143, NI 6154
SC Express
Signal Conditioning: NI 4300, NI 4302, NI 4303, NI 4304, NI 4305, NI 4322, NI 4330, NI 4331, NI 4339, NI 4353, NI 4357
DSA Series
Sound and Vibration: NI 4431, NI 4432, NI 4461, NI 4462, NI 4463, NI 4464, NI 4472/B, NI 4474, NI 4492, NI 4495, NI 4496, NI 4497, NI 4498, NI 4499, NI 4610
CompactDAQ
Platform to be used with I/O Modules:
Not Supported
C Series
Network DAQ
USB DAQ
I/O Modules to be paired with Chassis: NI 92xx, NI 94xx
NI MyDAQ
Educational: NI MyDAQ
Compact DAQ systems are not supported.
Questions?
If you have any questions regarding supported devices or if you are unsure of which NI-DAQ component to use, please contact us to discuss.
The following diagrams show wiring setups for connecting and synchronizing NI-DAQ devices with Prime series motion capture systems. Please note that NI-DAQ devices can be synchronized either through reference clock sync or through recording trigger sync, and both approaches are shown below. For most precise synchronization, using external clock signal as the reference is recommended.
OptiTrack mocap systems use the eSync 2 to provide highly accurate synchronization. When synchronizing the NI-DAQ device through an external clock signal or the reference clock signal, the eSync 2 generates and outputs clock signal to the NI-DAQ device(s), so that it can be used as the master reference clock that the connected devices can synchronize to. This approach is referred to as the reference clock sync, and in this approach, the data samples collected from two systems will be aligned on a per frame basis.
Wiring the eSync 2 and the NI-DAQ device: Connect one of the output ports of the eSync 2 into a programmable function interface (PFI) terminal of the NI-DAQ device that supports external sample clock inputs. For screw input terminals, ground signals must be separated from the BNC output of the eSync 2 and relayed into a digital ground terminal.
Wiring analog devices with the NI-DAQ device: Connect the output of an analog device(s) into one of the analog input channels of the NI-DAQ device. For screw terminals, a corresponding ground signal needs to be connected to an analog ground channel. For BNC terminals, wiring the ground signal is not necessary, but the input ports should be configured to either FS (Floating Source) or GS (Ground Source) setting depending on the characteristic of the signal source. For more information on connecting peripheral devices into a NI-DAQ device, visit NI support.
Screw Terminal Device Cabling
BNC Terminal Cabling
Required for setups using reference clock synchronization
In order to utilize the clock signal, a NI-DAQ device(s) that supports external sample clock input must be used. When using DAQ devices without the sample clock support, they will not be able to reference the clock signal. In this case, the device will have to sync at the start of the recording through the triggered sync and operate in the Free Run mode with independent acquisition rate which may result in synchronization drift over time.
NI-DAQ models supporting external sample clock:
X Series: (e.g. PCIe 6320, USB 63XX Series)
Bus-Powered M Series: ( e.g. USB 6210)
M Series: (e.g. USB 6221, PCI 6220)
Non-USB B Series: (e.g. PCI-6010)
NI-DAQ models NOT supporting external sample clock:
Low cost USB Series (e.g. USB-6002)
For best results, the reference clock sync approach is recommended to achieve per-sample basis synchronization between two systems; however, there are cases where this is not applicable. For example, you may need to use the clock signal to sync other devices that are sampling at a different rate than the sampling rate of the NI-DAQ device you wish to achieve. In such cases, you can use recording signal to trigger sync both systems at the start of the recording and have them free-run at their own sampling rates. This will align the recorded samples from two systems, but long recordings may be susceptible to phase shift.
Wiring the eSync 2 and the NI-DAQ device: Connect one of the output ports of the eSync 2 into an analog input terminal (e.g. ai0) of the NI-DAQ device. For screw input terminals, ground signals must be separated from the BNC output of the eSync 2 and relayed into an analog ground terminal.
Wiring analog devices with the NI-DAQ device: Connect the output of an analog device(s) into one of the analog input channels of the NI-DAQ device. For screw terminals, a corresponding ground signal needs to be connected to an analog ground channel. For BNC terminals, wiring the ground signal is not necessary, but the input ports should be configured to either FS (Floating Source) or GS (Ground Source) setting depending on the characteristic of the signal source. For more information on connecting peripheral devices into a NI-DAQ device, visit NI support.
Screw Terminal Device Cabling
BNC Terminal Cabling
For Motive to communicate with NI-DAQ devices, the OptiTrack Peripheral Modules must be installed along with Motive and NI-DAQ device drivers. The OptiTrack Peripherals Module is a software plugin package that installs required drivers and plugin DLLs for integrating external devices, including NI-DAQ devices and force plates (AMTI and Bertec). The following section describes the steps on integrating NI-DAQ device(s) within Motive.
During the Motive installation process, optional program features will be listed in the Custom Setup section. Here, change the setting for the Peripherals Device, as shown in the below image, so that the module is installed along with Motive.
After agreeing to install the Peripheral Device, the installer will ask to install NI-DAQmx 15.1.1 driver. You will need to install this driver for MS Windows to recognize the connected NI-DAQ devices. Press Yes to initiate the NI-DAQmx installation and follow the instructions to set up the driver.
Installation Note: For integration into Motive, the NI-DAQmx 15.1.1 or later runtime driver must be installed. If you are already using an older version of the NI-DAQmx runtime and Motive is having problems recognizing the connected device, update the driver or uninstall and re-install the packaged version of the driver before contacting Support. In Motive, you can inspect device connection status via the Log Pane which can be accessed under the View tab in Motive.
Ensure the NI-DAQ device is powered and detected by MS Windows. For USB DAQ devices, you could also use the installed NI Device Monitor software to confirm and monitor the connection. The NI Device Monitor can be accessed from the Windows taskbar tray when a USB DAQ device is connected.
In the Devices pane, all of the connected NI-DAQ devices will be listed along with respective analog input channels (up to 32) under the Data Acquisition group.
Once the NI-DAQ device is recognized properly, you will be able to observe the real-time signal on the Graph View pane.
a. Device Pane: Select a NI-DAQ channel with an active signal.
b. Device Pane: Toggle the NI-DAQ device to begin sampling.
c. Device Pane: Select the active channel.
d. Graph Pane: Show the 'Scope' View.
6. Zero the DAQ device
Detected voltage signals from a NI-DAQ input channels can be zeroed. Right-click on a NI-DAQ device from the Devices pane and click Zero. Doing this will zero all of the enabled channels for the selected NI-DAQ device.
Now that the device is detected in Motive, you can select and configure settings for the device and its analog channels through Motive. When a data acquisition device or an analog channel is selected in the Devices pane, their respective properties will be displayed on the Properties pane or on a separate pop-up for the analog channels.
Properties of connected NI-DAQ devices get listed in the Properties pane when a device is selected in the Devices pane. These properties need to be configured in order to properly synchronized the data acquisition device and the camera system together. Details about appropriate property settings will be covered in the following section.
For specific details about each properties, visit Properties: NI-DAQ page.
Depending on the model, NI-DAQ devices may have different sets of allowable input types and voltage ranges for their analog channels. Refer to your NI-DAQ device User's Guide for detailed information about supported signal types and voltage ranges.
(Default: -10 volts) Configure the terminal's minimum voltage range.
(Default: +10 volts) Configure the terminal's maximum voltage range.
Configures the measurement mode of the selected terminal. In general, analog input channels with screw terminals use the single-ended measurement system (RSE), and analog input channels with BNC terminals use the differential (Diff) measurement system. For more information on these terminal types, refer to NI documentation.
Terminal: RSE Referenced single ended. Measurement with respect to ground (e.g. AI_GND) (Default)
Terminal: NRSE NonReferenced single ended. Measurement with respect to single analog input (e.g. AISENSE)
Terminal: Diff Differential. Measurement between two inputs (e.g. AI0+, AI0-)
Terminal: PseudoDiff Differential. Measurement between two inputs and impeded common ground.
Notes on devices with Diff terminals
Motive will report all terminals detected through the device. Some BNC NI-DAQ models wrap two RSE terminals into each BNC Diff terminals (e.g. USB-6212: 16 RSE terminals into 8 Diff terminals), and it will report all RSE terminals into Motive. This means the actual number of channels reported in Motive may be more than the actual number of Diff terminals on the device. In this case, there will be an error message when attempting to enable channels that are not available. Please be aware of the device specification and enable only the Diff channels that are available on the device.
In order to precisely synchronize the motion capture system with NI-DAQ devices, the eSync 2 must be used. This section walks through the steps on configuring the settings of the eSync 2 and the NI-DAQ in order to synchronize two systems together through the reference clock sync or the recording trigger sync.
Reference clock synchronization keeps Motive and your device continuously synchronized every few frames. In Motive 3.0+ achieving this level of synchronization is easier than ever with new right click menus in the Devices pane.
1. [Hardware]: Connect one of the eSync 2 Output(N) ports into the NI-DAQ digital input terminal.
2. [Motive]: Open the Devices pane.
3. [Motive: Devices pane]: Right click the eSync 2 in the Devices pane and choose one of the "Biomech Presets".
4. [Motive: Devices pane] Right click the eSync 2 in the Devices pane, hover over the "Reference Clock" option, hover over the eSync 2 Output # used in step 1, then choose the corresponding DAQ PFI #.
5. [Motive: Control Panel] Record. The recorded NI-DAQ device samples will be synchronized with the external clock signal outputted from the eSync 2.
The internal clock signal is generated from the eSync 2 and outputted to the NI-DAQ device(s) for precisely synchronizing two systems together. This approach is referred to as the synchronization through reference sample clock signal, and in this setup, all of the data samples will be synchronized per-frame basis.
To configure this, set the Source to Internal Clock in the Sync Input Settings section under the eSync properties. Here, the clock frequency of the internal clock signal will basically set the sampling rate of the NI-DAQ device(s). Then, the input divider/multiplier can be adjusted to achieve desired camera frame rate, and the final camera system framerate will be calculated and indicated under the eSync properties and in the Devices pane. The following steps summarize the reference sample clock sync setup steps:
1. [Hardware]: Connect one of the eSync 2 Output(N) ports into the NI-DAQ digital input terminal.
2. [Motive]: Open the Devices pane and the Properties pane.
3. [Motive: Devices pane]: Select the eSync 2 in the Devices pane and the corresponding properties will be displayed in the Properties pane
4. [Motive: Properties pane (eSync 2)]: Configure the Sync Source to Internal Clock.
5. [Motive: Properties pane (eSync 2)] Set the Clock Freq to desired acquisition rate of the NI-DAQ device(s).
6. [Motive: Properties pane (eSync 2)] Adjust the Input Divider/Multiplier to set the final frame rate for the camera system. In order to accurately sample analog signals, the acquisition rate of the NI-DAQ device(s) should not be greater than X16 of the configured camera frame rate. In other words, the Input Divider should not exceed 16. The final camera system frame rate will always be displayed under the Devices pane and the eSync properties.
7. [Motive: Properties pane (eSync 2)] For the eSync 2 output ports connected to the NI-DAQ devices, set the Output(N) Type to Internal Clock. Now the internal clock signal is configured to be outputted through the output(N) port into the connected NI-DAQ channel.
8. [Motive: Devices pane] Select the NI-DAQ device in the Devices pane and the corresponding properties will be displayed in the Properties pane.
9. [Motive: Properties pane (NI-DAQ)] Within the NI-DAQ device property, set the Reference Clock Sync to True. At this point, the sampling rate of the NI-DAQ device in the Device Panel should be set to the same frequency as the internal clock signal configured for the eSync 2.
10. [Motive: Properties pane (NI-DAQ)] Under the NI-DAQ device properties, designate the Reference Clock Terminal to the NI-DAQ digital input terminal connected in Step 1.
11. [Motive: Control Panel] Record. The recorded NI-DAQ device samples will be synchronized with the external clock signal outputted from the eSync 2.
For best results, use the external clock sync approach to achieve per-sample basis synchronization between two systems. However, there are cases where this is not applicable. For example, you may need to use the external clock signal to sync other devices that are sampling at a different rate than the sampling rate of the NI-DAQ device you wish to achieve. In such cases, you can use recording signal to trigger sync both systems at the start of the recording and have them free-run at their own sampling rates. This will align the recorded samples from two systems, but long recordings may be susceptible to phase shift.
1. [Hardware]: Connect one of the eSync 2 Output(N) ports into the NI-DAQ analog input terminal.
2. [Motive]: Open the Devices pane and the Properties pane.
3. [Motive: Devices pane]: Select the eSync 2 in the Devices pane and the corresponding properties will be displayed in the Properties pane
4. [Motive: Properties pane (eSync 2)]: Configure the Sync Source under the Sync Input Settings. You can set it to either Internal Free Run or Internal Clock.
When this is set to Internal Clock, the camera system will reference the clock signal from the eSync 2 to determine the system frame rate. You will be able to configure the clock frequency and apply dividers and multipliers as necessary under the eSync 2 properties.
When this is set to Internal Free Run, the camera system will not reference the clock signal but will operate at its own rate which can be adjusted directly from the Devices pane.
5. [Motive: Properties pane (eSync 2)] For the eSync 2 output ports connected to the NI-DAQ devices, set the Output(N) Type to Recording Gate. This will configure the respective output ports to send out a signal into the connected NI-DAQ channel when Motive is recording.
6. [Motive: Devices pane] Select the NI-DAQ device in the Devices pane and the corresponding properties will be displayed in the Properties pane.
7. [Motive: Properties pane (NI-DAQ)] Within the NI-DAQ device property, set the Recording Trigger to Device.
8. [Motive: Properties pane (NI-DAQ)] Within the NI-DAQ device property, set the Reference Clock Sync to False.
9. [Motive: Properties pane (NI-DAQ)] Within the NI-DAQ device property, set a value for the Multiple section. This will set the NI-DAQ to sample at a rate multiple of the master system rate, which was configured in step 4. Since NI-DAQ will be free running after the initial trigger sync, it is important that it samples at a whole multiple of the master rate.
10. [Motive: Properties pane (NI-DAQ)] Under the NI-DAQ device properties, designate the Trigger Terminal to the analog input terminal connected in Step 1.
11. [Motive: Control Deck] Click the record button to initiate the recording, and both the camera system and NI-DAQ will start recording simultaneously using the trigger signal.
The following steps describe a general workflow on collecting signals from connected NI-DAQ channels in Motive. Make sure the camera system is calibrated before recording if you wish to collect tracking data along with the analog signals.
Notes on the analog samples at the end of the recording:
Please note that the integration is not stop-aligned. At the end of the recording, there may be a few more NI-DAQ samples recorded beyond the recorded mocap frames because NI-DAQ reports samples in a batch and records at a much higher acquisition rate.
Captured analog signals are recorded within the Take file and they can be played back in Motive. When in Edit mode, the integrated NI-DAQ device will be shown under the Assets pane, and its Analog measurements can be plotted on the Graph View pane. You will need to create a custom graph layout and enable plotting of analog channels:
Graph Layout with Analog Plots
Right-click on the graph view and set the desired layout dimensions.
On one of the graphs, right-click and under the Devices section, select the analog channels you wish to plot.
Recorded NI-DAQ analog channel data can be exported into C3D and CSV files along with the mocap tracking data. You can just follow the normal the tracking data export steps, and if the analog data exists in the TAK, they will also be exported.
C3D Export: Both mocap data and the analog data will be exported onto a same C3D file. Please note that all of the analog data within the exported C3D files will be logged at the same sampling frequency. If any of the devices are captured at different rates, Motive will automatically resample all of the analog devices to match the sampling rate of the fastest device. More on C3D files: https://www.c3d.org/
CSV Export: When exporting tracking data into CSV, additional CSV files will be exported for each of the NI-DAQ devices in a Take. Each of the exported CSV files will contain basic properties and settings at its header, including device information and sample counts. The voltage amplitude of each analog channel will be listed. Also, mocap frame rate to device sampling ratio is included since analog data is usually sampled at higher sampling rates.
Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
This page demonstrates a sample system setup involving multiple external devices. Specifically, one National Instruments Data Acquisition (NI-DAQ) device, two force plates, and a recording trigger will be integrated. Only basic step-by-step instructions will be covered in this guide. For detailed explanation of each device integrations, visit the following pages:
Motive
Motive: the Peripheral Device module and the NI-DAQmx plugin (15.1.1 or later).
Ethernet camera system with the eSync synchronization hub.
USB NI-DAQ: Supported Devices with external sample clock support.
Force Plate System: Bertec or AMTI
Record Trigger device (external device)
For general instructions on setting up the mocap system, refer to the Hardware Setup pages. This guide assumesthe camera system and the eSync 2 have been already installed.
Step 1. [Hardware Setup]
First of all, connect the external devices to the appropriate input or output ports of the eSync 2.
NI-DAQ (child): Connect one of the Output ports of the eSync 2 to an input terminal of the USB NI-DAQ device. The input terminal must support external sample clock signals in order to sync with the clock signal from the eSync 2. When integrating bare wire DAQ devices, respective ground signals must be separated from the BNC port. Sync Signal: Internal Clock
Force Plates (child): Connect the Output ports of the eSync 2 to a sync input port on the force plate amplifier. Sync Signal: Recording Pulse (AMTI) / Recording Gate (Bertec) for triggered sync. External clock sync cannot be used in this setup, because the clock signal will be used mainly for synchronizing the NI-DAQ device which usually runs at a faster sampling rate.
Recording Trigger (trigger): Using sync cables, connect the trigger device into one of the Input ports of the eSync 2.
Bertec AM6800: For Bertec systems using the AM6800 amplifier, the eSync's output port connects to the ANALOG OUTPUT port of the amplifier. The female 15-pin D-Sub connector included with the Bertec system must be used to separate the ZERO and SYNC cables. The ZERO cable connects to the eSync's output port, and the SYNC cable connects between force plate amplifiers. See: Bertec Hardware Setup
Connect the USB cables from the force plates and the NI-DAQ device to the host PC.
For integrating force plates and NI-DAQ devices, the Peripheral Device module and the NI-DAQmx driver must be installed along with Motive; both of which can be installed during the Motive installation process.
If the devices are properly recognized, they will be listed under the Devices pane in Motive.
Place the calibration wand on the force plate so that vertex of the wand is located at the right-hand corner of the side where the cable input is located (as shown in the image below). A correct placement of the calibration square is important because it determines the orientation of the force plate and its local coordinate axis within the global system. The coordinate systems for force plates are independent of the system used Motive.
Right-click on the NI-DAQ device or the force plates either on the Devices pane or on the Perspective View and click Zero. This will tare the devices and set the currently detected voltage/force to zero.
Now, let's configure the synchronization setup. This is done through configuring the properties of the eSync. Open the Devices pane and the Properties pane. Select the eSync under the list of devices and its properties will be listed out in the Properties pane. Here, you can adjust the properties to change the sync source, sync input/output behaviors.
First of all, you need to select and configure the sync input source. In this setup, the Internal Clock signal of the eSync will be used to synchronize the camera system. Set the Sync Input: Source to Internal Clock.
Once the Internal Clock is selected as the sync source, configure the clock signal:
Clock Freq (Hz): This sets the frequency of the clock signal. In this setup, the clock signal will be used to sync the camera system frame rate and also the acquisition rate of the NI-DAQ devices. Since the NI-DAQ devices usually sample at a higher frame rate, first set the clock frequency to the desired NI-DAQ sampling rate and apply input divider and multiplier for the camera system.
Input Trigger/Divider/Multiplier: Adjust the input divider and multiplier to derive the camera system frame rate from the configured internal clock signal. The final frame rate will be displayed at the bottom of the Sync Input section. Only the supported camera frame rate can be applied.
Step 10. [Motive → Properties: eSync 2] Configure the Sync Outputs.
Now, configure the output signal into the child devices. Configure the corresponding output port that each device is connected.
NI-DAQ: Set the output type of the connected output port to Gated Internal Clock signal. This will set the eSync 2 so that the internal clock is sent out when Motive starts recording.
Force Plates: Set the output type of the connected output port to Recording Gate (Bertec) or Recording Pulse (AMTI). The force plate systems will synchronize with the recording trigger from the eSync 2.
AMTI Force plates can also be synchronized through Gater Internal Clock signal. See AMTI Force Plate Setup page for more information.
Step 11. [Motive: → Properties: eSync]] Configure the Remote Trigger device.
Now let's configure the Record Trigger device. Under the Record Triggering section, set the trigger source to the input port that the device is connected to, and select appropriate trigger edge depending on the morphology of the trigger signal.
Step 12. [Motive: → Properties: eSync]] Apply the configuration.
Now that the eSync properties have been configured, the sync chain of the connected devices should be set up. Next step is to configure the properties of the external devices.
Step 13. [Motive → Properties: NI-DAQ] Configure NI-DAQ properties in Motive
Click on the NI-DAQ device under the Devices pane and open the Properties pane to configure its sync properties. The following configuration sets the NI-DAQ devices to synchronize its data acquisition with the clock signal from the eSync.
Use External Clock: True.
NIDAQExternalClockTerminal: Designate input channel of the NI-DAQ.
SyncMode: Free Run.
Step 14. [Motive → Properties: Force Plate]
Click on the Force Plate device under the Devices pane and open the Properties pane to configure its sync properties. The following configuration sets the force plates to trigger sync to the recording signal from the eSync 2:
Record Trigger: Device
Use External Clock: False
Sync Mode: Free Run
Now the systems are synchronized. When you start recording in Motive, precisely aligned data will be collected.
To utilize the external recording trigger device, press the record button in Motive and set it to a standby mode. Then use the device to send the recording trigger to the eSync 2, which will either initiate or stop recording each time a trigger is received.
This page is intended for a general overview of setting up Motive with force plates. Please visit the following pages for specific force plate setup from the different manufacturers:
In order to integrate force plate systems with Motive, you will need to setup the required drivers and plugins. Motive installer is packaged with the Peripheral Device module which can be added. During the Motive installation, a list of program features will be shown in the Custom Setup section. Here, change the setting for the Peripheral Device module, as shown in the below image, so that the module is installed along with Motive Files.
Note : Even if you are not using NI-DAQ, it is still necessary to install NI-DAQmx drivers that come up next in the installer.
1. Start Motive
If the hardware and software for the force plates are configured and successfully recognized, Motive will list out the detected force plates with number labels (1, 2, etc..). Motive will notify you of incorrect or nonexistent force plate calibration files. When the devices are successfully instantiated in Motive, the Log pane will indicate that the device has been created and loaded.
2. Calibrate Cameras
Calibrate the capture volume as normal to get the orientation of the cameras (see the Quick Start Guide or Calibration page for more information). The position of the force plate is about the center of the volume, and when you recalibrate or reset the ground plane, you will need to also realign the position of your force plates for best results.
3. Setup CS-400
On the CS-400 calibration square, pull the force plate alignment tabs out and put the force plate leveling jigs at the bottom. The leveling jigs align the calibration square to the surface of your force plate. The alignment tabs allow you to put the CS-400 flush against the sides of your force plate giving the most accurate alignment.
4. Place CS-400 on force plate
Place the calibration wand on the force plate so that vertex of the wand is located at the right-hand corner of the side where the cable input is located (as shown in the image below). A correct placement of the calibration square is important because it determines the orientation of the force plate and its local coordinate axis within the global system. The coordinate systems for force plates are independent of the system used Motive.
5. Set force plate position in Motive.
After placing the calibration square on the force plate, select the CS-400 markers in Motive. Right click on the force plate you want to locate, and click Set Position. When there are multiple force plates in a volume, you may need to step on the force plate to find which platform the calibration square is on. In Motive, uncalibrated force plates will light up in green and a force vector will appear when you step on the plate. Repeat step 4 and 5 for other force plates as necessary.
Referencing to the markers on the calibration square, Motive defines the location of the force plate coordinate system within the global coordinate system.
Motive uses manufacturer defined X, Y, and Z mechanical-to-electrical center offset when calculating the force vector and the center of pressure. For digital based plates, this information is available from the SDK and also stored in the plate's on-board calibration data.
6. Zero force plates.
After you have calibrated each of your force plates, remove the CS-400 from the volume. Right click one of your force plates in Motive and click Zero (all). This will tare the scale and set the current force on the plate data to 0. This will account for a small constant amount of measurement offset from the force plate. Remember that it zeros all of the force plates at once. So make sure there are no objects on any of the force plates.
7. Set sampling rate
Sampling rate of force plates is configured through the synchronization setup which will be covered in the following section. You can sync the force plates either through the reference clock sync or through the triggered sync. Please note that only specific sampling rates may be supported depending on the amplifier models.
There are two synchronization approaches you could take: Synchronization through clock signal or through recording trigger signal.
Synchronization via clock signal utilizes the internal clock signal of the eSync to synchronize the sampling of the force plates on per-frame basis. However, when there is another device (e.g. NI-DAQ) being synchronized to the clock signal frequency, the sampling rate cannot be set for each individual device. In that case, triggered sync must be used for synchronizing the initial recording trigger. Synchronization via trigger signal utilizes the recording trigger in Motive to align the initial samples from both systems. After the initial sync, both systems run freely at their own sampling rate. If the force plates are running at whole multiples of the camera system, the collected samples will be aligned. However, since the sampling clocks are not perfectly accurate, alignment of the samples may slowly drift over time. Thus, when synchronizing via recording trigger, it is better to keep the record times short.
When synchronizing through the eSync, use the following steps to configure the sync settings in Motive. This will allow both systems to be triggered simultaneously with reference to the parent synchronization device, the eSync.
Reference Clock Sync Setup Steps
Open the Devices pane and the Properties pane.
In the Devices pane, select the eSync among the listed devices. This will list out the synchronization settings in the properties pane for the selected eSync.
In the Properties pane, under Sync Input Settings section, set the Source to Internal Clock.
Next, to the Clock Frequency section, input the sampling rate that you wish the run the force plates in. This clock signal will be eventually outputted to the force plate system to control the sampling rate. For this guide, let's set this to 1200 Hz.
Once the clock frequency is set, apply the Input Divider/Multiplier to the clock frequency to set the framerate of the camera system. For example, if you set the Input Divider to 10 and the Input Multiplier to 2 with internal clock frequency running at 1200 Hz, the camera system will be running at 240 FPS. The resulting frame rate of the camera system will be displayed in the Camera Rate section.
Next step is to configure the output signal so that the clock signal can be sent to the force plate system. Under the Outputs section, enable the corresponding output port of the eSync which the force plate system is connected to.
Set the Output 1-4 → Type to Internal Clock.
Now that the eSync has been configured, you need to configure the force plate properties in Motive. While the force plate(s) is selected in Motive, access the Properties pane to view the force plate properties. Here, set the following properties:
Record Trigger → False
Reference Clock Sync → True
eSync Output Channel → output port used on the eSync.
Once this is set, the force plate system will start sampling at the frequency of the clock signal configured on the eSync, and this rate will be displayed on the Devices pane as well.
eSync 2 Settings Tip:
In Motive 3.0 and above, you can quickly configure eSync into biomech sync settings by right-clicking on the eSync from the Devices pane and select one of the presets from the context menu. This will enable and set all of the eSync outputs to the Internal Clock and set the clock frequency.
Live Data
Starting from Motive 3.0, clock synchronization in Live mode is supported, and the force vector visualization will be available both in Live and Edit modes.
Triggered Sync Setup Steps
Open the Devices pane and the Properties pane.
The final frame rate of the camera system will be displayed at the very top of the Devices pane.
In the Devices pane, select the eSync among the listed devices. This will list out the synchronization settings in the Properties pane for the selected eSync.
Set up the output signal so that the recording trigger signal can be sent to the force plate system. In the Outputs section, enable and configure the corresponding output port of the eSync which the force plate system is connected to.
Set the Output 1-4 → Type to Recording Gate.
Now that the eSync has been configured, you need to configure the properties of the force plates. While the force plate(s) is selected in Motive, access the Properties pane to view the force plate properties. Here, set the following properties:
Record Trigger → Device
Reference Clock Sync → False
eSync Output Channel → output port used on the eSync.
Once this is done, the force plate system will synchronize to the recording trigger signal when Motive starts collecting data, and the force plates will free-run after the initial sync trigger. You can configure the sampling rate of the force plates by modifying the Multiplier values in Devices pane to sample at a whole multiple of the camera system frame rate.
For free run sync setups, sampling rates of force plates can be set from the Devices pane, but the sampling rate of force plates must be configured to a whole multiple of the camera system's framerate. By adjusting the Rate Multiplier values in the Devices pane, sampling rates of the force plates can be modified. First, pick a frame rate of the camera system and then adjust the rate multiplier values to set force plates to the desired sampling rate.
ReSynch
When two systems are synchronized by recording trigger signals (Recording Gate or Recording Pulse), both systems are in Free Run Mode. This means that the recording of both the mocap system and the force plate system are triggered simultaneously at the same time and each system runs at its own rate.
Two systems, however, are synchronized at the recording trigger but not by per frame basis. For this reason, alignment of the mocap data and the force plate data may gradually drift from each other for longer captures. But this is not a problem since the sync chain will always be re-synchronized each time recording in Motive is triggered. Furthermore, Takes in general do not last too long for this drift to take effect on the data.
However, this could be an issue when live-streaming the data since recording is never initiated and two systems will be synchronized only when Motive first launches. To zero out the drift, the ReSynch feature can be used. Right-click on force plates from either the Devices pane or the perspective view, and select Resynch from the context menu to realign the sampling timing of both systems.
Before you start recording, you may want to validate that the camera and force plate data are in sync. There are some tests you can do to examine this.
The first method is to record dropping a retroreflective ball/marker onto the platform few times. The bouncing ball produces a sharp transition when it hits the surface of the platform, and it makes the data more obvious for validating the synchronization. Alternately, you can attach a marker on a tip of the foot and step on and off the force plate. Make sure that your toe — closest to the marker — strikes the platform first, otherwise the data will seem off even when it is not. You can then monitor the precise timing of the ball or the foot impacting the force plate and compare them between the mocap data and the force plate data.
The following is an example of validating good synchronization outcomes:
All of the configured device settings, including the calibration, get saved on Device Profile XML files. When you exit out of Motive, updated device profiles will be saved under the program data directory (C:\ProgramData\OptiTrack\Motive\DeviceProfiles), and this file gets loaded again when you restart Motive. You can have this file backed up to persist configured eSync and device settings. Also, if you wish to reset the device settings, you can remove XML files other than the default one from the folder, and Motive will load from the default settings.
Force plate data can be monitored from the Graph View pane. You will need to either use a provided Force Plate Forces layout or configure a custom graph layouts to show force plate data. To view the force plate data, make sure the corresponding force plates are selected, or selection-locked, in Motive.
If you are configuring your own force plate graph layout, make sure the desired force plate data channels (Fx, Fy, Fz, Mx, My, or Mz) are selected to be plotted. Then, when you select a force plate in Motive, and the data from the corresponding channels will be plotted on the graphs. When both reconstructed markers and force plate channels are selected, the force plot will be sub-sampled in order to be plotted along with trajectory data. For more information about how to configure graph layouts, read through the Graph View pane page.
Notes
The force and moment data reflects the coordinate system defined by the force plate manufacturer, which is typically the Z-down right-handed coordinate system. Note: This convention is independent of the global coordinate system used in Motive. Thus, the Fz components represent the vertical force. For more in-depth information, refer to the force plate specifications.
We recommend the following programs for analyzing exported data in biomechanics applications:
Motive exports tracking data and force plate data into C3D files. Exported C3D files can then be imported into a biomechanics analysis and visualization software for further processing. See the Data Export or Data Export: C3D page for more information about C3D export in Motive. Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
C3D Axes
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Force plate data and the tracking data can be exported into CSV files as well. When a Take file is exported into a CSV file. Separate CSV files will be saved for each force plate and it will contain the force, moment, and center of pressure data. Exported CSV file can be imported for analysis.
To stream tracking data along with the force plate data, open the Data Streaming Pane and check the Broadcast Frame Data, and make sure that you are not streaming over the camera network. Read more about streaming from the Data Streaming workflow page.
Motive can stream the tracking data and the force plate data into various applications — including Matlab — using NatNet Streaming protocol. Find more about NatNet streaming from the User's Guide included in the download.
Number of Force Plates
At the time of writing, there is a hard limit on the maximum number of force plate data that can be streamed out from Motive. Please note that only up to 8 force plate data can be streamed out from Motive and received by a NatNet SDK 4.0 application.
From the Devices pane, Motive reports the state of the force plate. Below is the icon associated with each state.
Force plate is either not enabled, or the position has not been set.
The position has been set, but the force plate is not yet streaming data.
This page provides instructions on how to integrate a Kistler force plate system with an OptiTrack motion capture system.
When a motion capture system is used in conjunction with force plates, they work together as an efficient tool for various research applications including biomechanical analysis, clinical gait analysis, physiology research, sports performance research, and many more. An OptiTrack motion capture system can synchronize with force plates to obtain both kinematic and kinetic measurements. Note that force plate integration is supported only with a Prime camera system using the eSync 2 synchronization hub. This page provides quick guidelines for setting up and configuring force plates — with digital outputs — along with the OptiTrack motion capture system.
For detailed information on specifications and configurations on the force plates, refer to the documentation provided by the force plate manufacturer.
Analog Platforms
Analog force plate devices can only be implemented via DAQ devices. Incoming voltage signals can be detected through the data acquisition channels, but force plate related software features (vectors, position calibration, etc.) will not be supported in Motive for the analog platforms. Refer to the page for detailed instructions on integrating analog devices.
Starting from Motive 3.0, reference clock synchronization while in Live mode is supported.
Kistler Data Acquisition System
Kistler Force Plate
Control I/O, Sync breakout box
Prime series Ethernet camera system with the eSync 2 synchronization hub.
Motive 2.1 or above.
Connect each force plate to the Data Acquisition device, and connect the USB uplink cable from the acquisition device to the host PC. For detailed instructions on setting up the Force Plate system with a host PC, refer to the Kistler documentation.
Hot plugging is not supported with the integration. When a new device is connected to the system, you must re-start Motive to instantiate it.
Before integrating Kistler force plates into Motive, make sure all of the components required by Kistler system are set up on the computer. This includes BioWare software, the device driver (InstaCal), and other required software components. The force plate system must be recognized by Kistler's software before it can be used in Motive.
Once they are all installed, launch the BioWare software and register each force plate. During this process, you will input device information such as model number, serial number, and platform specs to configure the device setting. For more information, please refer to manufacturer documentation.
In order to integrate force plate systems with Motive, you will need to setup the required drivers and plugins. Motive installer is packaged with the Peripheral Device module which can be added. During the Motive installation, a list of program features will be shown in the Custom Setup section. Here, change the setting for the Peripheral Device module, as shown in the below image, so that the module is installed along with Motive Files.
Note : Even if you are not using NI-DAQ, it is still necessary to install NI-DAQmx drivers that come up next in the installer.
For Kistler Customers
Kistler system also requires Microsoft Visual C++ 2010 Redistributable - x64 to be installed on the computer. If it is not already on the computer, you will get prompted to set this up during Motive installation process. Please make sure to have this installed as well.
After registering the force plate in BioWare, next step is to export out the device configuration XML file. In BioWare, go to the Setup → Save DataServer Configuration File to export out the configuration XML file. To add the Kistler force plates in Motive, this XML file containing the force plate information must be added to the Motive directory. Copy-and-paste the Configuration.xml file into the C:\ProgramData\OptiTrack\Motive\DeviceProfiles directory, and then rename the file to Kistler.xml. Once this is done, Motive should initialize the force plates that are detected by computer and that are registered within the XML file.
1. Start Motive
2. Calibrate Cameras
3. Setup CS-400
4. Place CS-400 on force plate
Place the calibration wand on the force plate so that vertex of the wand is located at the right-hand corner of the side where the cable input is located (as shown in the image below). A correct placement of the calibration square is important because it determines the orientation of the force plate and its local coordinate axis within the global system. The coordinate systems for force plates are independent of the system used Motive.
AMTI Force Plates
AMTI force plates use the right-hand system. The long arm of CS-400 will define the Y axis, and the short arm will define the X axis of the force plate. Accordingly, Z axis is directed downwards for measuring the vertical force.
5. Set force plate position in Motive.
After placing the calibration square on the force plate, select the CS-400 markers in Motive. Right click on the force plate you want to locate, and click Set Position. When there are multiple force plates in a volume, you may need to step on the force plate to find which platform the calibration square is on. In Motive, uncalibrated force plates will light up in green and a force vector will appear when you step on the plate. Repeat step 4 and 5 for other force plates as necessary.
Referencing to the markers on the calibration square, Motive defines the location of the force plate coordinate system within the global coordinate system.
Motive uses manufacturer defined X, Y, and Z mechanical-to-electrical center offset when calculating the force vector and the center of pressure. For digital based plates, this information is available from the SDK and also stored in the plate's on-board calibration data.
6. Zero force plates.
After you have calibrated each of your force plates, remove the CS-400 from the volume. Right click one of your force plates in Motive and click Zero (all). This will tare the scale and set the current force on the plate data to 0. This will account for a small constant amount of measurement offset from the force plate. Remember that it zeros all of the force plates at once. So make sure there are no objects on any of the force plates.
7. Set sampling rate
Sampling rate of force plates is configured through the synchronization setup which will be covered in the following section.
Supported force plate sampling rates: Kistler plates support rates sampling rates between 10~2000 Hz. Make sure the synchronization is configured that the force plates sample at the supported speed.
There are two synchronization approaches you could take: Synchronization through clock signal or through recording trigger signal.
Synchronization via clock signal utilizes the internal clock signal of the eSync to synchronize the sampling of the force plates on per-frame basis. However, when there is another device (e.g. NI-DAQ) being synchronized to the clock signal frequency, the sampling rate cannot be set for each individual device. In that case, triggered sync must be used for synchronizing the initial recording trigger. Synchronization via trigger signal utilizes the recording trigger in Motive to align the initial samples from both systems. After the initial sync, both systems run freely at their own sampling rate. If the force plates are running at whole multiples of the camera system, the collected samples will be aligned. However, since the sampling clocks are not perfectly accurate, alignment of the samples may slowly drift over time. Thus, when synchronizing via recording trigger, it is better to keep the record times short.
When synchronizing through the eSync, use the following steps to configure the sync settings in Motive. This will allow both systems to be triggered simultaneously with reference to the parent synchronization device, the eSync.
Reference Clock Sync Setup Steps
Next, to the Clock Frequency section, input the sampling rate that you wish the run the force plates in. This clock signal will be eventually outputted to the force plate system to control the sampling rate. For this guide, let's set this to 1200 Hz.
Once the clock frequency is set, apply the Input Divider/Multiplier to the clock frequency to set the framerate of the camera system. For example, if you set the Input Divider to 10 and the Input Multiplier to 2 with internal clock frequency running at 1200 Hz, the camera system will be running at 240 FPS. The resulting frame rate of the camera system will be displayed in the Camera Rate section.
Next step is to configure the output signal so that the clock signal can be sent to the force plate system. Under the Outputs section, enable the corresponding output port of the eSync which the force plate system is connected to.
Record Trigger → False
Reference Clock Sync → True
eSync Output Channel → output port used on the eSync.
eSync 2 Settings Tip:
Live Data
Starting from Motive 3.0, clock synchronization in Live mode is supported, and the force vector visualization will be available both in Live and Edit modes.
Triggered Sync Setup Steps
Set up the output signal so that the recording trigger signal can be sent to the force plate system. In the Outputs section, enable and configure the corresponding output port of the eSync which the force plate system is connected to.
Record Trigger → Device
Reference Clock Sync → False
eSync Output Channel → output port used on the eSync.
ReSynch
When two systems are synchronized by recording trigger signals (Recording Gate or Recording Pulse), both systems are in Free Run Mode. This means that the recording of both the mocap system and the force plate system are triggered simultaneously at the same time and each system runs at its own rate.
Two systems, however, are synchronized at the recording trigger but not by per frame basis. For this reason, alignment of the mocap data and the force plate data may gradually drift from each other for longer captures. But this is not a problem since the sync chain will always be re-synchronized each time recording in Motive is triggered. Furthermore, Takes in general do not last too long for this drift to take effect on the data.
Before you start recording, you may want to validate that the camera and force plate data are in sync. There are some tests you can do to examine this.
The first method is to record dropping a retroreflective ball/marker onto the platform few times. The bouncing ball produces a sharp transition when it hits the surface of the platform, and it makes the data more obvious for validating the synchronization. Alternately, you can attach a marker on a tip of the foot and step on and off the force plate. Make sure that your toe — closest to the marker — strikes the platform first, otherwise the data will seem off even when it is not. You can then monitor the precise timing of the ball or the foot impacting the force plate and compare them between the mocap data and the force plate data.
The following is an example of validating good synchronization outcomes:
All of the configured device settings, including the calibration, get saved on Device Profile XML files. When you exit out of Motive, updated device profiles will be saved under the program data directory (C:\ProgramData\OptiTrack\Motive\DeviceProfiles), and this file gets loaded again when you restart Motive. You can have this file backed up to persist configured eSync 2 and device settings. Also, if you wish to reset the device settings, you can remove XML files other than the default one from the folder, and Motive will load from the default settings.
Notes
The force and moment data reflects the coordinate system defined by the force plate manufacturer, which is typically the Z-down right-handed coordinate system. Note: This convention is independent of the global coordinate system used in Motive. Thus, the Fz components represent the vertical force. For more in-depth information, refer to the force plate specifications.
We recommend the following programs for analyzing exported data in biomechanics applications:
C3D Axes
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Force plate data and the tracking data can be exported into CSV files as well. When a Take file is exported into a CSV file. Separate CSV files will be saved for each force plate and it will contain the force, moment, and center of pressure data. Exported CSV file can be imported for analysis.
Number of Force Plates
Configuring force plate sampling rate from .This page provides instructions on how to integrate a Bertec force plate system with an OptiTrack motion capture system.
When a motion capture system is used in conjunction with force plates, they work together as an efficient tool for various research applications including biomechanical analysis, clinical gait analysis, physiology research, sports performance research, and many more. An OptiTrack motion capture system can synchronize with force plates to obtain both kinematic and kinetic measurements. Note that force plate integration is supported only with a Prime camera system using the eSync synchronization hub. This page provides quick guidelines for setting up and configuring force plates — with digital outputs — along with the OptiTrack motion capture system.
For detailed information on specifications and configurations on the force plates, refer to the documentation provided by the force plate manufacturer.
Analog Platforms
Analog force plate devices can only be implemented via DAQ devices. Incoming voltage signals can be detected through the data acquisition channels, but force plate related software features (vectors, position calibration, etc.) will not be supported in Motive for the analog platforms. Refer to the page for detailed instructions on integrating analog devices.
Motive 3.0 Update
Starting from Motive 3.0, reference clock synchronization while in Live mode is supported.
Supported Amplifier Models: AM6800
Firmware Version: For synchronization support, the Bertec amplifiers must be installed with firmware version 46A. The current firmware version gets displayed on the amplifier display when first powering up the amplifier. Please check this and make sure the firmware is updated to the supported versions.
Prime series Ethernet camera system with the eSync synchronization hub.
Motive 3.0 or above.
Motive 2.2 or 2.3 users should use firmware version 4.5.2.
Bertec amplifiers currently only support a fixed sampling rate of 1000 Hz
Refer to the respective Bertec system user documentation for detailed information on setting up the force plate system and connecting to the host PC.
Wiring the eSync with the Amplifier
Hot plugging is not supported with the integration. When a new device is connected to the system, you must re-start Motive to instantiate it.
Reference Clock Sync
The SYNC cable from the amplifier needs to be connected to the output port of the eSync for synchronization with the camera system.
Triggered Sync Cabling
Bertec AM 6800 amplifiers: Use the provided female 15-pin D-Sub connector to get the ZERO signal and the SYNC signal from the ANALOG OUTPUT port of the amplifier.
The ZERO cable from the amplifier needs to be connected to the output port of the eSync for synchronization with the camera system.
The SYNC cable from the amplifier needs to be interconnected between the force plate amplifiers for their internal sync. When using more than one plates, a BNC connector or a BNC splitter will need to be used to interconnect the SYNC cables between multiple amplifiers.
In order to integrate force plate systems with Motive, you will need to setup the required drivers and plugins. Motive installer is packaged with the Peripheral Device module which can be added. During the Motive installation, a list of program features will be shown in the Custom Setup section. Here, change the setting for the Peripheral Device module, as shown in the below image, so that the module is installed along with Motive Files.
Note : Even if you are not using NI-DAQ, it is still necessary to install NI-DAQmx drivers that come up next in the installer.
In addition to the Peripheral Device module, you may also want to install the Digital Acquire™ from Bertec to verify that the force plates are properly working. Visit the below webpage to download the software, and follow the respective instructions to install. This software installs remaining resources for connecting the Bertec force plates.
Place the calibration wand on the force plate so that vertex of the wand is located at the right-hand corner of the side where the cable input is located (as shown in the image below). A correct placement of the calibration square is important because it determines the orientation of the force plate and its local coordinate axis within the global system. The coordinate systems for force plates are independent of the system used Motive.
After placing the calibration square on the force plate, select the CS-400 markers in Motive. Right click on the force plate you want to locate, and click Set Position. When there are multiple force plates in a volume, you may need to step on the force plate to find which platform the calibration square is on. In Motive, uncalibrated force plates will light up in green and a force vector will appear when you step on the plate. Repeat step 4 and 5 for other force plates as necessary.
Referencing to the markers on the calibration square, Motive defines the location of the force plate coordinate system within the global coordinate system.
Motive uses manufacturer defined X, Y, and Z mechanical-to-electrical center offset when calculating the force vector and the center of pressure. For digital based plates, this information is available from the SDK and also stored in the plate's on-board calibration data.
Tip: To double check that the dimensions are modified properly, you can place extra retroreflective markers on each corner of the platform and monitor the coincidence of the markers position with the force plate assets from the perspective view.
After you have calibrated each of your force plates, remove the CS-400 from the volume. Right click one of your force plates in Motive and click Zero (all). This will tare the scale and set the current force on the plate data to 0. This will account for a small constant amount of measurement offset from the force plate. Remember that it zeros all of the force plates at once. So make sure there are no objects on any of the force plates.
8. Set sampling rate
Sampling rate of force plates is configured through the synchronization setup which will be covered in the following section. You can sync the force plates either through the reference clock sync or through the triggered sync. Please note that only specific sampling rates may be supported depending on the amplifier models.
Supported Force Plate Sampling Rates
Reference Clock Signal Sync: When using the reference clock signal from the eSync to synchronize the force plates, the force plate will basically run at the same rate as the received clock signal. You can also apply either the multiplier or the divider to the outputted clock signal to make additional adjustments.
There are two synchronization approaches you could take: Synchronization through clock signal or through recording trigger signal.
Synchronization via clock signal utilizes the internal clock signal of the eSync 2 to synchronize the sampling of the force plates on per-frame basis. However, when there is another device (e.g. NI-DAQ) being synchronized to the clock signal frequency, the sampling rate cannot be set for each individual device. In that case, triggered sync must be used for synchronizing the initial recording trigger. Synchronization via trigger signal utilizes the recording trigger in Motive to align the initial samples from both systems. After the initial sync, both systems run freely at their own sampling rate. If the force plates are running at whole multiples of the camera system, the collected samples will be aligned. However, since the sampling clocks are not perfectly accurate, alignment of the samples may slowly drift over time. Thus, when synchronizing via recording trigger, it is better to keep the record times short.
When synchronizing through the eSync 2, use the following steps to configure the sync settings in Motive. This will allow both systems to be triggered simultaneously with reference to the parent synchronization device, the eSync 2.
IMPORTANT NOTE: For this synchronization setup to work properly, the Bertec amplifier firmware must be updated to firmware version 46A or above. Currently installed firmware version gets displayed on the 7-segment display when first powering up the amplifier. Please check this and make sure the firmware is updated to the supported versions. If an older version is installed, please contact Bertec for instructions on updating the firmware.
Reference Clock Sync Setup Steps
Next, to the Clock Frequency section, input the sampling rate that you wish the run the force plates in. This clock signal will be eventually outputted to the force plate system to control the sampling rate. For this guide, let's set this to 1000 Hz.
Once the clock frequency is set, apply the Input Divider/Multiplier to the clock frequency to set the framerate of the camera system. For example, if you input 10 to the Input Divider section with internal clock frequency running at 1000 Hz, the camera system will be running at 100FPS. The resulting frame rate of the camera system will be displayed in the Camera Rate section.
Next step is to configure the output signal so that the clock signal can be sent to the force plate system. Under the Outputs section, enable the corresponding output port of the eSync 2 which the force plate system is connected to.
Triggered Sync → None
Reference Clock Sync → True
eSync 2 Output Channel → output port used on the eSync 2.
eSync Settings Tip:
Live Data
Starting from Motive 3.0, clock synchronization in Live mode is supported, and the force vector visualization will be available both in Live and Edit modes.
Triggered Sync Setup Steps
Set up the output signal so that the recording trigger signal can be sent to the force plate system. In the Outputs section, enable and configure the corresponding output port of the eSync which the force plate system is connected to.
Record Trigger → Device
Reference Clock Sync → False
eSync Output Channel → output port used on the eSync.
Sampling Rate
Supported Frame Rate: When synchronizing two systems via recording trigger, the force plates will be running at their own free-run frame rate. In this case, only 1000 Hz sampling rate is supported for Bertec force plates. If you wish to sample at a different rate, please use the reference clock sync approach.
ReSynch
When two systems are synchronized by recording trigger signals (Recording Gate or Recording Pulse), both systems are in Free Run Mode. This means that the recording of both the mocap system and the force plate system are triggered simultaneously at the same time and each system runs at its own rate.
Two systems, however, are synchronized at the recording trigger but not by per frame basis. For this reason, alignment of the mocap data and the force plate data may gradually drift from each other for longer captures. But this is not a problem since the sync chain will always be re-synchronized each time recording in Motive is triggered. Furthermore, Takes in general do not last too long for this drift to take effect on the data.
Before you start recording, you may want to validate that the camera and force plate data are in sync. There are some tests you can do to examine this.
The first method is to record dropping a retroreflective ball/marker onto the platform few times. The bouncing ball produces a sharp transition when it hits the surface of the platform, and it makes the data more obvious for validating the synchronization. Alternately, you can attach a marker on a tip of the foot and step on and off the force plate. Make sure that your toe — closest to the marker — strikes the platform first, otherwise the data will seem off even when it is not. You can then monitor the precise timing of the ball or the foot impacting the force plate and compare them between the mocap data and the force plate data.
The following is an example of validating good synchronization outcomes:
All of the configured device settings, including the calibration, get saved on Device Profile XML files. When you exit out of Motive, updated device profiles will be saved under the program data directory (C:\ProgramData\OptiTrack\Motive\DeviceProfiles), and this file gets loaded again when you restart Motive. You can have this file backed up to persist configured eSync and device settings. Also, if you wish to reset the device settings, you can remove XML files other than the default one from the folder, and Motive will load from the default settings.
Notes
The force and moment data reflects the coordinate system defined by the force plate manufacturer, which is typically the Z-down right-handed coordinate system. Note: This convention is independent of the global coordinate system used in Motive. Thus, the Fz components represent the vertical force. For more in-depth information, refer to the force plate specifications.
We recommend the following programs for analyzing exported data in biomechanics applications:
C3D Axes
Common Conventions
Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
X axis in Motive should be configured to positive X
Y axis in Motive should be configured to negative Z
Z axis in Motive should be configured to positive Y.
This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
Force plate data and the tracking data can be exported into CSV files as well. When a Take file is exported into a CSV file. Separate CSV files will be saved for each force plate and it will contain the force, moment, and center of pressure data. Exported CSV file can be imported for analysis.
Number of Force Plates
At the time of writing, there is a hard limit of 4 Bertec force plates that can be used in Motive due to Bertec SDK limitations.
Open the Devices pane in Motive and connected Trigno device will be listed. If you click on the on the device, and all of the available data channels will be shown in the pop-up. Click on the data channels and enable the ones that will be used.
The graph layout may need to be configured for plotting the EMG channel data. To create a new layout, click on the button in Graph pane and select Create New Layout from the context menu. Once new layout is created, click on the icon to expand the sidebar, and click on the graph which you wish to plot the graphs onto, and check mark the EMG channels in the sidebar to start plotting the channel data onto the selected graph. Make sure Trigno device is selected under the Devices pane.
First, make sure the NI-DAQ device and its operating analog input channels are enabled under the Devices pane. Then, open the Graph pane and create a custom layout for monitoring live-analog data; create a new layout, right-click on the graphs, and select the device channel you wish to plot. Then, open the graph editor () and make sure View Style is set to Live under the Visuals tab. Configured analog channels will be plotted on the graphs.
Properties of individual channels can be configured directly from the Devices pane. As shown in the image, you can click on the icon to bring up the settings and make changes.
The force plate is now streaming data into Motive. *Note this doesn't guarantee that the force plate data and Motive are synchronized. Please see above for more information.
Setup the OptiTrack camera system and place the force plate(s) at the desired location(s); ideally, near the center of the volume. See or page for details.
For accurate synchronizations, the must be used. The eSync 2 has signal output ports that are used to send out synchronization signals to child devices. Connect the BNC output ports of the eSync to sync input ports (Genlock/Trigger Input) of force plate amplifiers.Kistler force plates have a sync I/O breakout (Control I/O) accessory that connects to the amplifier. The eSync will connect to one of the inputs of this sync I/O box. For triggered sync, connect the output port of the eSync to the Trigger Input. For external clock sync, connect the output to the Sync Input of the sync I/O box.
If the hardware and software for the force plates are configured and successfully recognized, Motive will list out the detected force plates with number labels (1, 2, etc..). Motive will notify you of incorrect or nonexistent force plate calibration files. When the devices are successfully instantiated in Motive, the will indicate that the device has been created and loaded.
Calibrate the capture volume as normal to get the orientation of the cameras (see the or page for more information). The position of the force plate is about the center of the volume, and when you recalibrate or reset the ground plane, you will need to also realign the position of your force plates for best results.
On the , pull the force plate alignment tabs out and put the force plate leveling jigs at the bottom. The leveling jigs align the calibration square to the surface of your force plate. The alignment tabs allow you to put the CS-400 flush against the sides of your force plate giving the most accurate alignment.
Open the and the .
In the , select the eSync among the listed devices. This will list out the synchronization settings in the properties pane for the selected eSync.
In the , under Sync Input Settings section, set the Source to Internal Clock.
Set the Output 1-4 → Type to .
Now that the eSync has been configured, you need to configure the force plate properties in Motive. While the force plate(s) is selected in Motive, access the Properties pane to view the . Here, set the following properties:
Once this is set, the force plate system will start sampling at the frequency of the clock signal configured on the eSync, and this rate will be displayed on the as well.
In Motive 3.0 and above, you can quickly configure eSync into biomech sync settings by right-clicking on the eSync from the and select one of the presets from the context menu. This will enable and set all of the eSync outputs to the Internal Clock and set the clock frequency.
Open the and the .
The final frame rate of the camera system will be displayed at the very top of the .
In the , select the eSync among the listed devices. This will list out the synchronization settings in the Properties pane for the selected eSync.
Set the Output 1-4 → Type to .
Now that the eSync has been configured, you need to configure the properties of the force plates. While the force plate(s) is selected in Motive, access the Properties pane to view the . Here, set the following properties:
Once this is done, the force plate system will synchronize to the recording trigger signal when Motive starts collecting data, and the force plates will free-run after the initial sync trigger. You can configure the sampling rate of the force plates by modifying the Multiplier values in to sample at a whole multiple of the camera system frame rate.
For free run sync setups, sampling rates of force plates can be set from the , but the sampling rate of force plates must be configured to a whole multiple of the camera system's framerate. By adjusting the Rate Multiplier values in the , sampling rates of the force plates can be modified. First, pick a frame rate of the camera system and then adjust the rate multiplier values to set force plates to the desired sampling rate.
However, this could be an issue when live-streaming the data since recording is never initiated and two systems will be synchronized only when Motive first launches. To zero out the drift, the ReSynch feature can be used. Right-click on force plates from either the or the , and select Resynch from the context menu to realign the sampling timing of both systems.
Force plate data can be monitored from the . You will need to either use a provided Force Plate Forces layout or configure a custom graph layouts to show force plate data. To view the force plate data, make sure the corresponding force plates are selected, or selection-locked, in Motive.
If you are configuring your own force plate graph layout, make sure the desired force plate data channels (Fx, Fy, Fz, Mx, My, or Mz) are selected to be plotted. Then, when you select a force plate in Motive, and the data from the corresponding channels will be plotted on the graphs. When both reconstructed markers and force plate channels are selected, the force plot will be sub-sampled in order to be plotted along with trajectory data. For more information about how to configure graph layouts, read through the page.
Motive exports tracking data and force plate data into C3D files. Exported C3D files can then be imported into a biomechanics analysis and visualization software for further processing. See the or page for more information about C3D export in Motive. Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
To stream tracking data along with the force plate data, open the Data Streaming Pane and check the Broadcast Frame Data, and make sure that you are not streaming over the camera network. Read more about streaming from the workflow page.
Motive can stream the tracking data and the force plate data into various applications — including Matlab — using protocol. Find more about from the User's Guide included in the download.
At the time of writing, there is a hard limit on the maximum number of force plate data that can be streamed out from Motive. Please note that only up to 8 force plate data can be streamed out from Motive and received by a application.
Set up an OptiTrack system. Connect the camera system to the same host PC. For more information, refer to the page or the pages.
Link:
If the hardware and software for the force plates are configured and successfully recognized, Motive will list out the detected force plates with number labels (1, 2, etc..). Motive will notify you of incorrect or nonexistent force plate calibration files. When the devices are successfully instantiated in Motive, the will indicate that the device has been created and loaded.
Calibrate the capture volume as normal to get the orientation of the cameras (see the or page for more information). The position of the force plate is about the center of the volume, and when you recalibrate or reset the ground plane, you will need to also realign the position of your force plates for best results.
On the , pull the force plate alignment tabs out and put the force plate leveling jigs at the bottom. The leveling jigs align the calibration square to the surface of your force plate. The alignment tabs allow you to put the CS-400 flush against the sides of your force plate giving the most accurate alignment.
If the force plate dimensions are not automatically configured, you need to enter the dimensions of the force plate in the force plate properties after calibrating its positions. Go to the and select the force plate, and its properties will get listed under the . Enter the length and width (in inches) values for the corresponding plates as reported in the specifications.
Note: Zeroed scales of Bertec force plates are saved within their software driver, and each time the driver restarts, these settings are refreshed. This means that the force plate zero setting will be refreshed each time you start Motive, or each time the device is disabled and enabled back again in Motive. Please be aware of this behavior and zero your plates when necessary. In Motive, there is a Zero On Enable property setting for Bertec force plates under the , and enabling this setting will automatically zero your plate each time the device is enabled or when Motive restarts. The Zero On Enable setting is enabled by default.
Recording Trigger Sync: When using the recording signal from the eSync to trigger-sync the force plates, the force plates will be running at their own free run sampling rate. In this case, only 1000 Hz sampling rate is supported, and you will need to adjust the camera frame rate in the and apply framerate-multipliers to set the 1000 Hz sampling rate on the force plates.
Open the and the .
In the , select the eSync 2 among the listed devices. This will list out the synchronization settings in the properties pane for the selected eSync 2.
In the , under Sync Input Settings section, set the Source to Internal Clock.
Set the Output 1-4 → Type to .
Now that the eSync 2 has been configured, you need to configure the force plate properties in Motive. While the force plate(s) is selected in Motive, access the Properties pane to view the . Here, set the following properties:
Once this is set, the force plate system will start sampling at the frequency of the clock signal configured on the eSync 2, and this rate will be displayed on the as well.
In Motive 3.0 and above, you can quickly configure eSync into biomech sync settings by right-clicking on the eSync from the and select one of the presets from the context menu. This will enable and set all of the eSync outputs to the Internal Clock and set the clock frequency.
Open the and the .
The final frame rate of the camera system will be displayed at the very top of the .
In the , select the eSync among the listed devices. This will list out the synchronization settings in the Properties pane for the selected eSync.
Set the Output 1-4 → Type to .
Now that the eSync has been configured, you need to configure the properties of the force plates. While the force plate(s) is selected in Motive, access the Properties pane to view the . Here, set the following properties:
Once this is done, the force plate system will synchronize to the recording trigger signal when Motive starts collecting data, and the force plates will free-run after the initial sync trigger. You can configure the sampling rate of the force plates by modifying the Multiplier values in to sample at a whole multiple of the camera system frame rate.
Setting Framerate Multiplier: For free run sync setups, sampling rates of force plates can be set from the , but the sampling rate of force plates must be configured to a whole multiple of the camera system's framerate. By adjusting the Rate Multiplier values in the , sampling rates of the force plates can be modified. First, pick a frame rate of the camera system and then adjust the rate multiplier values to set force plates to the desired sampling rate.
However, this could be an issue when live-streaming the data since recording is never initiated and two systems will be synchronized only when Motive first launches. To zero out the drift, the ReSynch feature can be used. Right-click on force plates from either the or the , and select Resynch from the context menu to realign the sampling timing of both systems.
Force plate data can be monitored from the . You will need to either use a provided Force Plate Forces layout or configure a custom graph layouts to show force plate data. To view the force plate data, make sure the corresponding force plates are selected, or selection-locked, in Motive.
If you are configuring your own force plate graph layout, make sure the desired force plate data channels (Fx, Fy, Fz, Mx, My, or Mz) are selected to be plotted. Then, when you select a force plate in Motive, and the data from the corresponding channels will be plotted on the graphs. When both reconstructed markers and force plate channels are selected, the force plot will be sub-sampled in order to be plotted along with trajectory data. For more information about how to configure graph layouts, read through the page.
Motive exports tracking data and force plate data into C3D files. Exported C3D files can then be imported into a biomechanics analysis and visualization software for further processing. See the or page for more information about C3D export in Motive. Note that the coordinate system used in Motive (y-up right-handed) may be different from the convention used in the biomechanics analysis software.
To stream tracking data along with the force plate data, open the Data Streaming Pane and check the Broadcast Frame Data, and make sure that you are not streaming over the camera network. Read more about streaming from the workflow page.
Motive can stream the tracking data and the force plate data into various applications — including Matlab — using protocol. Find more about from the User's Guide included in the download.
