Installation

Host PC Requirements

Required PC specifications may vary depending on the size of the camera system. Generally, a system with more than 24 cameras will require the recommended specs to run properly.

Download Motive

Download the Motive installer from the OptiTrack Support website. Click Downloads > Motive to find the latest version of Motive, or previous releases, if needed.

Both Motive: Body and Motive: Tracker use the same software installer.

Installation Steps

Run the Installer

When the download is complete, run the installer to begin the installation.

Install the USB Driver and Dependencies

When installing Motive for the first time, the installer will prompt you to install the OptiTrack USB Driver. This driver is required for all OptiTrack USB devices, including the Security Key. You may also be prompted to install other dependencies such as the C++ redistributable, which is included in the Motive installer. After all dependencies have been installed, Motive will resume its installation.

Install Motive

Follow the installation prompts and install Motive in your desired file directory. We recommend installing the software in the default directory, C:\Program File\OptiTrack\Motive.

OptiTrack Peripheral Module

At the Custom Setup section of the installation process, you will be prompted to choose whether to install the Peripheral Devices along with Motive. If you plan to use force plate, NI-DAQ, or EMG devices along with the motion capture system, the Peripheral Devices must be installed.

If you are not going to use these devices, you may skip to the next step.

Finish Installation

Once all the steps above are completed, Motive is installed. If you want to use additional plugins, visit the downloads page.

Host PC Setup

The following settings are sufficient for most mocap applications. The page Windows 11 Optimization for Realtime Applications has our recommended configuration for more demanding uses.

Firewall / Antivirus

We recommend isolating the camera network and the host PC so that firewall and antivirus protection are not required. That will not be possible in situations where the host PC is connected to a corporate or institutional network. If so:

• Make sure all antivirus software installed on the Host PC allows Motive traffic.

• For Ethernet cameras, make sure the windows firewall is configured so the camera network is recognized.

Potential issues that can occur if antivirus software is installed:

• Some programs (i.e., BitDefender, McAfee, etc.) may block Motive from downloading. The Motive software downloaded directly from OptiTrack.com/downloads is safe for use and will not harm your computer.

• If you're unable to view cameras in the Devices pane, or you are seeing frame/data drops, verify that the antivirus or firewall settings allow all traffic from your camera network to Motive and vice versa.

• Antivirus software may need to be completely uninstalled if it continues to interfere with camera communication.

High Performance

Windows power saving mode limits CPU usage, which can impact Motive performance.

To best utilize Motive, set the Power Plan to High Performance. Go to Control Panel → Hardware and Sound → Power Options as shown in the image below.

Graphics Card Settings

Required only for computers with integrated graphics.

Computers that have integrated graphics on the motherboard in addition to a dedicated graphics card may switch to the integrated graphics when the computer goes to sleep mode. This may cause the Viewport to become unresponsive when the PC exits sleep mode.

To prevent this, set Motive to use high performance graphics only.

• Type Graphics in the Windows Search bar to find and open the Graphics settings, located at System > Display > Graphics.

• In the Add an app field, select Desktop app, then browse to the Motive executable: C:\Program Files\OptiTrack\Motive\Motive.exe.

• Motive will now appear in the list of customizable applications.

• Click Motive to display, then click, the Options button.

• Set the Graphics preference to High performance and click Save.

License Activation

Once Motive is installed, the next step is to activate the software using the Motive 3.x license information provided at the time of purchase, and attach the USB Security Key. The Security Key attaches to the Host PC either through a USB C port or using an adapter for USB A to USB C.

Security Key

For Motive 3.0 and above, a USB Security Key is required to use the camera system. This key is different from the previous Hardware Key and it improves the security of the camera system.

Security Keys are purchased separately. For more information, please see the following page:

• https://optitrack.com/accessories/license-keys/

License Types

There are five types of Motive licenses:

• Motive:Body-Unlimited

• Motive:Body

• Motive:Tracker

• Motive:Edit-Unlimited

• Motive:Edit

Each license unlocks different features in the software depending on the use case that the license is intended to facilitate.

• The Motive:Body and Motive:Body-Unlimited licenses are intended for either small (up to 3) or large-scale Skeleton tracking applications.

• The Motive:Tracker license is intended for real-time Rigid Body tracking applications.

• The Motive:Edit and Motive:Edit Unlimited licenses are intended for users modifying data after it has been captured (post production work).

For more information on different Motive licenses, check the software comparison table on our website. An abbreviated version is available in the table below.

Activate the License

Motive licenses are activated using the License Activation tool. This tool can be found:

• On the OptiTrack Support page.

• On the Host PC at C:\Program Files\OptiTrack\Motive\LicenseTool.

• On the Motive splash screen, when an active license is not installed.

License Activation Tool

• Launch Motive. If the license has been activated, the splash screen will appear momentarily before Motive loads. If not, the splash screen will display the License not found error and a menu.

• Click License Tool to open the License Activation Tool.

• The License Serial Number and License Hash were provided on a printed card (enclosed in an envelope) when the license was purchased. If the card is missing, this information is also located on the order invoice.

• The Security Key Serial Number is printed on the USB security key.

• If you have already activated the license on another machine, make sure to enter the same name when activating it on the new PC.

• Once you have entered all the information, click Activate. The license files will be copied into the license folder: C:\ProgramData\OptiTrack\License.

• Click Retry to finish loading Motive.

Online Activation Tool

The Online License Activation tool allows you to activate licenses from the OptiTrack Support page. This option requires more steps but is helpful if you are activating licenses for multiple systems or do not have access to the host PC to use the license tool from the splash screen.

• Enter the email address to send the license file(s) to in the E-mail Address field.

• The License Serial Number and License Hash are located on the order invoice.

• The Device Serial Number is printed on the USB security key.

• If you have already activated the license on another machine, make sure to enter the same name when activating it on the new PC.

• Once you have entered all the information, click Activate.

• The license file(s) will arrive via email. Check your spam filter and junk mail if you don't see it in your inbox.

• Download the license file(s) to the License Folder on the hard drive of the host PC: C:\ProgramData\OptiTrack\License.

• Insert the USB security key, then launch Motive.

License Details

Check My License

The Check My License tool allows you to lookup license information to obtain the expiration date.

About Motive Screen

About Motive includes information about the active license, which can be exported to a text file by clicking the Export... link at the bottom.

If Motive does not detect an active license, you can still open About Motive from the splash screen, however the only information available is the Machine ID.

Using Activated Software on a Different Computer

You can install Motive on more than one computer with the same license and security key, but you will not be able to use it on multiple PCs simultaneously. Only the PC with the security key connected will be able to run Motive.

Use the License Activation Tool

You can use the License Activation Tool to acquire the license files for the new host PC. This includes the initial license and any maintenance licenses that were purchased.

• When run from the Motive splash screen, the tool will download the license files directly

• When run from the OptiTrack Support website, the license files will be sent via emailed.

When using this method to transfer the license, enter the same contact information that was entered the first time the license was activated. We recommend exporting the license data to a text file from the original installation to use as a reference.

If the original information is lost, please contact OptiTrack Support for assistance.

Copy and Paste the License Files

The license file(s) can also be copied from one computer to another. License files are located at c:\ProgramData\OptiTrack\License. Open the license folder from the Motive Help menu.

If the files are copied from one PC to another, there is no need to re-run the License Activation Tool to begin using the currently active license. Simply install the version of Motive supported by the license and connect the security key.

More Questions?

For more information on licensing of Motive, refer to the Licensing FAQs from the OptiTrack website:

• http://optitrack.com/support/faq/licensing.html

For common licensing issues and troubleshooting recommendations, please see the Licensing Troubleshooting page.

For more questions, contact OptiTrack Support:

• http://optitrack.com/support/

• Please attach the LicenseData.txt file exported from the About Motive panel as a reference.

This page provides an overview of Motive's tools, configurations, navigation controls, and instructions on managing capture files. Links to more detailed instructions are included.

File Management

In Motive, motion capture recordings are stored in the Take (.TAK) file format in folders known as session folders.

The Data pane is the primary interface for managing capture files. Open the Data pane by clicking the icon on the main Toolbar to see a list of session folders and the corresponding Take files that are recorded or loaded in Motive.

Take Files (.TAK)

A .TAK file is a single motion capture recording (aka 'take' or 'trial'), which contains all the information necessary to recreate the entire capture, including camera calibration, camera 2D data, reconstructed and labeled 3D data, data edits, solved joint angle data, tracking models (Skeletons, Rigid Bodies, Trained Markersets), and any additional device data (audio, force plate, etc.). A Motive take (.TAK) file is a completely self-contained motion capture recording, that can be opened by another copy of Motive on another system.

Session Folders

The folder where take files are stored is known as a session folder in Motive. Session folders allow you to plan shoots, organize multiple similar takes (e.g. Monday, Tuesday, Wednesday, or Static Trials, Walking Trials, Running Trials, etc.) and manage complex sets of data within Motive or Windows.

For a most efficient workflow, plan the mocap session before the capture and organize a list of captures (shots) to be completed. Type the take names in a spreadsheet or a text file, then copy and paste the list into the data pane. This will create empty takes (a shot list) with corresponding names from the pasted list.

Click the button on the toolbar at the bottom of the Data pane to hide or expand the list of open Session Folders.

Alternately, with the session folder list closed, click the name of the current session folder in the top left corner for a quick selection.

Please refer to the Session Folders section of the Data pane page for more information on working with these folders.

Motive User Profile (.MOTIVE)

Software configuration settings are saved in the motive profile (*.motive) file, located by default at:

C:\ProgramData\OptiTrack\MotiveProfile.motive

The profile includes application-related settings, asset definitions, and the open session folders. The file is updated as needed during a Motive session and at exit, and loads again the next time Motive is launched.

The profile includes:

• Application Settings

• Live Pipeline Settings

• Streaming Settings

• Synchronization Settings

• Export Settings

• Rigid Body & Skeleton assets

• Rigid Body & Skeleton settings

• Labeling settings

• Hotkey configuration

Reset Settings

To revert all settings to Motive factory defaults, select Reset Application Settings from the Edit menu.

Calibration files (.CAL)

A calibration file is a standalone file that contains all the required information to restore a calibrated camera volume, including the position and orientation of each camera, lens distortion parameters, and camera settings. After a camera system is calibrated, the .CAL file can be exported and imported back into Motive again when needed. For this reason, we recommend saving the camera calibration file after each round of calibration.

Note that an imported .CAL file is reliable only if the camera setup has remained unchanged since the calibration. Read more from the Calibration page.

The calibration file includes:

• Reconstruction settings

• Camera settings

• Position and orientation of the cameras

• Location of the global origin

• Lens distortion of each camera

Viewports

In Motive, the main viewport is fixed at the center of the UI and is used to monitor the 2D or 3D capture data in both live capture and playback of recorded data. The viewports can be set to either Perspective View, which shows the reconstructed 3D data within the calibrated 3D space, or Cameras View, which shows 2D images from each camera in the system. These views can be selected from the drop-down menu at the top-right corner. By default, the Perspective View opens in the top pane and the Cameras view opens in the bottom pane. Both views are essential for assessing and monitoring the tracking data.

Perspective View - 3D

• Click on any viewport window and use the hotkey 1 to quickly switch to the Perspective view.

• Displays the reconstructed 3D representation of the capture.

• Used to analyze marker positions, view rays used in reconstruction, create assets, etc.

Cameras View - 2D

• Click on any viewport window and use the hotkey 2 to quickly switch to the Cameras View.

• This view displays the images transmitted from each camera, with a header that shows the camera's Video Mode (Object, Precision, Grayscale, or MJPEG) and resolution.

• Detected IR lights and reflections also show in this pane. Only IR lights that satisfy the object filters are identified as markers. See Cameras Basic Settings in the Settings: Live Pipeline page for more detail on object filters.

• Includes tools to report camera information, inspect pixels, troubleshoot markers, and mask pixel regions to exclude them from processing. See Cameras View in the Viewport page for more details.

Additional Viewports

Viewport Navigation Controls

Viewport Mouse Control

The table below lists basic actions that are commonly used for navigating the viewports in Motive:

Hotkeys

Control Deck

The Control Deck is always docked at the bottom of Motive, providing both recording and navigation controls over Motive's two operating modes: Live and Edit.

Live Mode

• All cameras are active and the system is processing camera data.

• If the system is calibrated, Motive live-reconstructs 2D camera data into labeled and unlabeled 3D trajectories (markers) in real-time.

• Live tracking data can stream to other applications using the data streaming tools or the NatNet SDK.

• The system is ready for recording. Capture controls are available in the Control Deck.

Edit Mode

• Used for processing a loaded Take file (pre-recorded data). Cameras are not active.

• Playback controls are available in the Control Deck, including a timeline (in green) at the top of the control deck for scrubbing through the recorded frames.

• Review recorded 3D data from the Take file, make post-processing edits and manually assign marker labels to the recorded trajectories before exporting the tracking data.

• When needed, you can switch from editing in 3D to 2D mode, to view the real-time unreconstructed 3D data. Use this to perform a post-processing reconstruction pipeline to re-obtain a new set of 3D data.

Graph View pane

The Graph View pane is used to plot live or recorded channel data. There are many uses cases for plotting data in Motive; examples include tracking 3D coordinates of the reconstructed markers, 3D positions and orientations of Rigid Body assets, force plate data, analog data from data acquisition devices, and many more.

You can switch between existing layouts or create a custom layout for plotting specific channel data.

Basic navigation controls are highlighted below. For more information on graphing data in Motive, please read the Graph View pane page.

Graph View Navigation Controls

Navigate Frames (Alt + Left-click + Drag )

Hold the Alt key while left-clicking and dragging the mouse left or right over the graph to navigate through the recorded frames. You can use the mouse scroll also.

Pan (Scroll-click + Drag)

Scroll-click and drag to pan the view vertically and horizontally throughout plotted graphs. Dragging the cursor left and right pans the view along the horizontal axis for all of the graphs. When navigating vertically, scroll-click on a graph and drag up and down to also pan vertically.

Zoom (Right-click + Drag)

Select Frame Range (Left-click + Drag)

Frame range selection is used when making post-processing edits on specific ranges of the recorded frames. Select a specific range by left-clicking and dragging the mouse left and right, and the selected frame ranges will be highlighted in yellow. You can also select more than one frame ranges by holding the shift key while selecting multiple ranges.

Graph View Navigation Bar

The Navigation Bar at the bottom of the Graph View pane can also be used to

Navigate Frames (Left-click)

Left-click and drag on the navigation bar to scrub through the recorded frames. You can use the mouse scroll also.

Pan View Range

Scroll-click and drag to pan the view range.

Frame Range Zoom

Zoom to a frame range by re-sizing the scope range using the navigation bar handles. As noted above, you can also do this by pressing Alt + right-clicking on the graph to select the range to zoom to.

Working Range / Playback range

The working range (also called the playback range) is both the view range and the playback range of a corresponding Take in Edit mode. In playback, only the working range will play, and in the Graph View pane, only the data for the working range will display.

The working range can be set from different places:

• In the navigation bar of the Graph View pane, drag the handles on the scrubber.

• Use the navigation controls on the Graph View pane to zoom in or zoom out on the desired range.

Selection Range

The selection range is used to apply post-processing edits only to a specific frame range of a Take. The selected frame range is highlighted in yellow on both Graph View pane and the Control Deck Timeline.

Gap Indication

When playing back a recorded capture, red marks on the navigation bar indicate areas with occlusions of labeled markers. Brighter colors indicate a greater number of markers with labeling gaps.

Application Settings

Motive's Application Settings panel holds application-wide settings, including:

• Startup configuration and display options for both 2D and 3D viewports.

• Settings for asset creation.

• Live-pipeline parameters for the Solver and the 2D Filter settings for the cameras.

  • The Cameras tab includes the 2D filter settings that determine which reflections are classified as marker reflections on the camera views.

  • The Solver settings determine which 3D markers are reconstructed in the scene from the group of marker reflections from all the cameras.

Live Pipeline > Solver Settings

The Solver tab on the Live Pipeline settings panel configures the real-time solver engine. These are some of the most important settings in Motive as they determine how 3D coordinates are acquired from the captured 2D camera images and how they are used for tracking Rigid Bodies and Skeletons. Understanding these settings is very important for optimizing the system for the best tracking results.

Live Pipeline > Camera Settings

Under the Camera tab, you can configure the 2D Camera filter settings (circularity filter and size filter) as well as other display options for the cameras. The 2D Camera filter setting is a key setting for optimizing the capture.

For most applications, the default settings work well, but it is still helpful to understand these core settings for more efficient control over the camera system.

Layouts

Predefined Layouts

Motive includes several predefined layouts suited to various workflow activities. Access them from the Layout menu, or use the buttons in the top right corner of the screen.

Customized Layouts

The User Interface (UI) layout in Motive is highly customizable.

• Select the desired panes from the View menu or from the standard toolbar.

• All panes can be undocked to float, dock elsewhere, or stack with other panes with a simple drag-and-drop.

• Reposition panes using on-screen docking guides:

• Drag-and-drop the pane over the icon for the desired position. To have the pane float, drop it away from the docking guides.

• Stacked panes form a tabbed window. The option to stack is only available when dragging a pane over another stackable pane.

• Custom layouts can be saved and loaded again, allowing a user to easily switch between default and custom configurations suitable for different needs.

  • Select Create Layout... from the Layout menu to save your custom layout.

  • The custom layout will appear in the selection list to the left of the Layout buttons.

• Custom layouts can also be accessed using HotKeys, with Ctrl+6 through Ctrl+9 set for user layouts by default.

Overview

In Motive, an Asset is a set of markers that define a specific object to be tracked in the capture. Asset tracking data can be sent to other pipelines (e.g., animations and biomechanics) for extended applications.

When an asset is created, Motive automatically applies a set of predefined labels to the reconstructed trajectories (markers) using Motive's tracking and labeling algorithms. Motive calculates the position and orientation of the asset using the labeled markers.

There are three types of assets, covering a full range of tracking needs:

• Rigid Bodies: used to track rigid, unmalleable, objects.

• Skeletons: used to track human motions.

• Trained Markersets: used to track any object that is not a Rigid Body or a pre-defined Skeleton.

This article provides an introduction to working with existing assets. For information specific to each asset type, click the links in the list above. Visit the Builder pane page for detailed instructions to create and modify each asset type.

Video Quick Start Guide: Asset Creation

The following video demonstrates the asset creation workflow.

Assets Pane

When an asset is selected, either from the Assets pane or from the 3D Perspective view, its related properties are displayed in the Properties pane.

Copying Assets

Follow these steps to copy an asset to other recorded TAKES or to the Live capture.

Copy Assets to a Recorded Take

1. Right-click the desired Take to open the context menu.

2. Select Copy Assets to Takes.

3. This will bring up a dialog window to select the assets to move.

4. Select the assets to copy and click Done.

Copy Assets to Multiple Recorded Takes

1. Use shift-click or ctrl-click to select Takes from the Data pane until all the desired Takes are selected.

2. Right-click any of the selected Takes. This should copy the assets you selected to all the selected Takes in the Data pane to open the context menu.

3. Select Copy Assets to Takes.

4. This will bring up a dialog window to select the assets to move.

5. Select the assets to copy and click Done.

Copy Assets from a Recorded Take to the Live Capture

1. To copy multiple assets, use shift-click or ctrl-click to select all of them in the Assets pane.

2. Right-click (one of) the asset(s).

3. Select Copy Assets to Live.

4. The asset(s) will now appear in the Assets pane in Live mode. Motive will recognize the asset when it enters the volume, based on its unique marker placement.

Exporting Assets

Assets can be exported into the Motive user profile file (.MOTIVE), where they can then be imported into different takes without creating a new asset.

The user profile is a text-readable file that contains various configuration settings, including the asset definitions. With regard to assets, profiles specifically store the spatial relationship of each marker in the asset, ensuring that only the identical marker arrangement will be recognized and defined with the imported asset.

To Export Assets:

1. From the File menu, select Export Assets...

2. This will copy all the asset definitions in either Live-mode or in the current Take file into the user profile.

Export User Profile

The option to export the user profile allows Motive users to save custom profiles as part of their project folders.

To export a user profile:

1. From the File menu, select Export Profile As...

2. The Export Profile window will open.

3. Navigate to the folder where you want the exported profile stored, or use the Motive default folder.

4. Select the profile elements to export. Options are: Properties, Hotkeys/Mouse Controls, Sessions, and Assets.

5. Name the file, using the File Type: Motive User Profile (*.motive).

6. Click Export.

OptiTrack motion capture systems can use both passive and active markers as indicators for 3D position and orientation. An appropriate marker setup is essential for both tracking the quality and reliability of captured data. All markers must be properly placed and must remain securely attached to surfaces throughout the capture. If any markers are taken off or moved, they will become unlabeled from the Marker Set and will stop contributing to the tracking of the attached object. In addition to marker placements, marker counts and specifications (sizes, circularity, and reflectivity) also influence the tracking quality. Passive (retroreflective) markers need to have well-maintained retroreflective surfaces in order to fully reflect the IR light back to the camera. Active (LED) markers must be properly configured and synchronized with the system.

Retroreflective Markers

OptiTrack cameras track any surfaces covered with retroreflective material, which is designed to reflect incoming light back to its source. IR light emitted from the camera is reflected by passive markers and detected by the camera’s sensor. Then, the captured reflections are used to calculate the 2D marker position, which is used by Motive to compute 3D position through reconstruction. Depending on which markers are used (size, shape, etc.) you may want to adjust the camera filter parameters from the Live Pipeline settings in Application Settings.

Marker Size

The size of markers affects visibility. Larger markers stand out in the camera view and can be tracked at longer distances, but they are less suitable for tracking fine movements or small objects. In contrast, smaller markers are beneficial for precise tracking (e.g. facial tracking and microvolume tracking), but have difficulty being tracked at long distances or in restricted settings and are more likely to be occluded during capture. Choose appropriate marker sizes to optimize the tracking for different applications.

Circularity

If you wish to track non-spherical retroreflective surfaces, lower the Circularity value in 2D object filter in the application settings. This adjusts the circle filter threshold and non-circular reflections can also be considered as markers. However, keep in mind that this will lower the filtering threshold for extraneous reflections as well. If you wish to track non-spherical retroreflective surfaces, lower the Circularity value from the cameras tab in the application settings.

Worn markers

All markers need to have a well-maintained retroreflective surface. Every marker must satisfy the brightness Threshold defined from the camera properties to be recognized in Motive. Worn markers with damaged retroreflective surfaces will appear to a dimmer image in the camera view, and the tracking may be limited.

Custom Markers

OptiTrack cameras can track any surface covered with retro-reflective material. For best results, markers should be completely spherical with a smooth and clean surface. Hemispherical or flat markers (e.g. retro-reflective tape on a flat surface) can be tracked effectively from straight on, but when viewed from an angle, they will produce a less accurate centroid calculation. Hence, non-spherical markers will have a less trackable range of motion when compared to tracking fully spherical markers.

Active Markers

OptiTrack Active Markers

OptiTrack's active solution provides advanced tracking of IR LED markers to accomplish the best tracking results. This allows each marker to be labeled individually. Please refer to the Active Marker Tracking page for more information.

Custom Active Markers

Active (LED) markers can also be tracked with OptiTrack cameras when properly configured. We recommend using OptiTrack’s Ultra Wide Angle 850nm LEDs for active LED tracking applications. If third-party LEDs are used, their illumination wavelength should be at 850nm for best results. Otherwise, light from the LED will be filtered by the band-pass filter.

If your application requires tracking LEDs outside of the 850nm wavelength, the OptiTrack camera should not be equipped with the 850nm band-pass filter, as it will cut off any illumination above or below the 850nm wavelength. An alternative solution is to use the 700nm short-pass filter (for passing illumination in the visible spectrum) and the 800nm long-pass filter (for passing illumination in the IR spectrum). If the camera is not equipped with the filter, the Filter Switcher add-on is available for purchase at our webstore. There are also other important considerations when incorporating active markers in Motive:

• Place a spherical diffuser around each LED marker to increase the illumination angle. This will improve the tracking since bare LED bulbs have limited illumination angles due to their narrow beamwidth. Even with wide-angle LEDs, the lighting coverage of bare LED bulbs will be insufficient for the cameras to track the markers at an angle.

• If an LED-based marker system will be strobed (to increase range, offset groups of LEDs, etc.), it is important to synchronize their strobes with the camera system. If you require a LED synchronization solution, please contact one of our Sales Engineers to learn more about OptiTrack’s RF-based LED synchronizer.

• Many applications that require active LEDs for tracking (e.g. very large setups with long distances from a camera to a marker) will also require active LEDs during calibration to ensure sufficient overlap in-camera samples during the wanding process. We recommend using OptiTrack’s Wireless Active LED Calibration Wand for best results in these types of applications. Please contact one of our Sales Engineers to order this calibration accessory.

Marker Placement

Proper marker placement is vital for quality of motion capture data because each marker on a tracked subject is used as indicators for both position and orientation. When an asset (a Rigid Body or Skeleton) is created in Motive, its unique spatial relationships of the markers are calibrated and recorded. Then, the recorded information is used to recognize the markers in the corresponding asset during the auto-labeling process. For best tracking results, when multiple subjects with a similar shape are involved in the capture, it is necessary to offset their marker placements to introduce the asymmetry and avoid the congruency.

Read more about marker placements from the Rigid Body Tracking page and the Skeleton Tracking page.

Marker Bases and Adhesives

Prepare the markers and attach them on the subject, a Rigid Body or a person. Minimize extraneous reflections by covering shiny surfaces with non-reflective tapes. Then, securely attach the markers to the subject using enough adhesives suitable for the surface. There are various types of adhesives and marker bases available on our webstore for attaching the marker: Acrylic, Rubber, Skin adhesive, and Velcro. Multiple types of marker bases are also available: carbon fiber filled bases, Velcro bases, and snap-on plastic bases.

This page provides instructions on how to utilize the Gizmo tool for modifying asset definitions (Rigid Bodies and Skeletons) on the 3D Perspective View of Motive

Overview

The gizmo tools allow users to make modifications on reconstructed 3D markers, Rigid Bodies, or Skeletons for both real-time and post-processing of tracking data. This page provides instructions on how to utilize the gizmo tools.

Rigid Body Assets

Using the gizmo tools from the perspective view options to easily modify the position and orientation of Rigid Body pivot points. You can translate and rotate Rigid Body pivot, assign pivot to a specific marker, and/or assign pivot to a mid-point among selected markers.

• Select Tool (Hotkey: Q): Select tool for normal operations.

• Translate Tool (Hotkey: W): Translate tool for moving the Rigid Body pivot point.

• Rotate Tool (Hotkey: E): Rotate tool for reorienting the Rigid Body coordinate axis.

• Scale Tool (Hotkey: R): Scale tool for resizing the Rigid Body pivot point.

Tutorial Videos

Rigid Bodies

Translation

Rotation

Rescale

Skeleton Assets

You can utilize the gizmo tools to modify skeleton bone lengths, joint orientations, or scale the spacing of the markers. Translating and rotating the skeleton assets will change how skeleton bone is positioned and oriented with respect to the tracked markers, and thus, any changes in the skeleton definition will affect the realistic representation of the human movement.

Translation

Rotation

Scale

The scale tool modifies the size of selected skeleton segments.

Reconstructed 3D Markers

The gizmo tools can also be used to edit positions of reconstructed markers.In order to do this, you must be working reconstructed 3D data in post-processing. In live-tracking or 2D mode doing live-reconstruction, marker positions are reconstructed frame-by-frame and it cannot be modified. The Edit Assets must be disabled to do this (Hotkey: T).

Translate

Using the translate tool, 3D positions of reconstructed markers can be modified. Simply click on the markers, turn on the translate tool (Hotkey: W), and move the markers.

Rotate

Using the rotate tool, 3D positions of a group of markers can be rotated at its center. Simply select a group of markers, turn on the rotate tool (Hotkey: E), and rotate them.\

Scale

Using the scale tool, 3D spacing of a group of makers can be scaled. Simply select a group of markers, turn on the scale tool (Hotkey: R) and scale their spacing.

Cameras

Cameras can be modified using the gizmo tool if the Settings Window > General > Calibration > "Editable in 3D View" property is enabled. Without this property turned on the gizmo tool will not activate when a camera is selected to avoid accidentally changing a calibration. The process for using the gizmo tool to fix a misaligned camera is as follows:

1. Select the camera you wish to fix, then view from that camera (Hotkey: 3).

2. Select either the Translate or Rotate gizmo tool (Hotkey: W or E).

3. Use the red diamond visual to align the unlabeled rays roughly onto their associated markers.

4. Right lock then choose "Correct Camera Position/Orientation". This will perform a calculation to place the camera more accurately.

5. Turn on Continuous Calibration if not already done. Continuous calibration should finish aligning the camera into the correct location.

During process, a calibration square is used to define global coordinate axes as well as the ground plane for the capture volume. Each calibration square has different vertical offset value. When defining the ground plane, Motive will recognize the square and ask user whether to change the value to the matching offset.

Vertical Offset

Motive accounts for the vertical offset when using a standard OptiTrack calibration square, setting the origin at the bottom corner of the calibration square rather than the center of the marker.

When using a custom calibration square, measure the distance between the center of the marker and the lowest tip at the vertex of the calibration square. Enter this value in the Vertical Offset field in the Calibration pane.

Coordinate System (Motive 1.7+)

For Motive 1.7 or higher, Right-Handed Coordinate System is used as the standard, across internal and exported formats and data streams. As a result, Motive 1.7 now interprets the L-Frame differently than previous releases:

In Motive, Skeleton assets are used for tracking human motions. These assets auto-label specific sets of markers attached to human subjects, or actors, and create skeletal models.

Unlike Rigid Body assets, Skeleton assets require additional calculations to correctly identify and label 3D reconstructed markers on multiple semi-Rigid Body segments. To accomplish this, Motive uses pre-defined Skeleton Marker Set templates that define a collection of marker labels and their specific positions on a subject.

Skeleton Marker Placement

When it comes to tracking human movements, proper marker placement is especially important. In Motive's pre-programmed Skeleton Marker Sets, each marker indicates an anatomical landmark, such as left elbow out, right hip, etc., when modeling the Skeleton. If markers are misplaced, the Skeleton asset may not be created, or bad marker placements may result in problems, creating extra work in post-processing of the data.

Attaching markers directly to a person’s skin can be difficult due to hair, oil, and moisture from sweat. For this reason, we recommend mocap suits that allow Velcro marker bases. In instances where markers must be attached directly, make sure to use appropriate skin adhesives to secure the marker bases as dynamic human motions tend to move the markers during capture.

Select a Marker Set

• Open the Create tab on the .

• From the Type drop-down list, select Skeleton.

• Select a Marker Set to use from the drop-down menu. The number of required markers for each Skeleton is shown in parenthesis after the Marker Set name.

• When a Marker Set is selected, the corresponding marker locations are displayed over an avatar in the . Right-drag to rotate the avatar to see the location of all the markers.

Placing the Markers

Have the subject strike a calibration pose (T-pose or A-pose) and carefully place retroreflective markers at the corresponding locations of the actor or the subject.

• The positions of markers shown in white are fixed and must be in the same location for each skeleton created. These markers are critical in auto-labeling the skeleton.

• The positions of markers shown in magenta are relative and should be placed in various positions in the general area to create skeletons that are unique to each actor.

Joint Markers

Joint markers need to be placed carefully along corresponding joint axes. Proper placements will minimize marker movements during a range of motions and will give better tracking results. To accomplish this, ask the subject to flex and extend the joint (e.g., knee) a few times and palpate the joint to locate the corresponding axis. Once the axis is located, attach the markers along the axis where skin movement is minimal during a range of motion.

Segment Markers

Segment markers are placed on Skeleton body segments, but not around a joint. For best tracking results, place segment markers asymmetrically within each segment. This helps the Skeleton solve to thoroughly distinguish left from right for the corresponding Skeleton segments throughout the capture. This asymmetrical placement is also emphasized in the avatars shown in the Builder pane.

Additional Placement Tips

• If attaching markers directly to skin, wipe off any moisture or oil before attaching the marker.

• Avoid wearing clothing or shoes with reflective materials that can introduce extraneous reflections.

• Tie up hair, which can occlude markers around the neck.

• Remove reflective jewelry.

• Place markers in an asymmetrical arrangement by offsetting the related segment markers (markers that are not on joints) at slightly different height.

Biomechanics Marker Sets

• The markers need to be placed on the skin for direct representation of the subject’s movement. Use appropriate adhesives to place markers and make sure they are securely attached.

• Place markers where you can palpate the bone or where there is less soft tissue in between. These spots have fewer skin movements and provide more secure marker attachment.

Calibration Markers

Many Skeleton Marker Sets do not have medial markers because they can easily collide with other body parts or interfere with the range of motion, all of which increase the chance of marker occlusions.

However, medial markers are beneficial for precisely locating joint axes by associating two markers on the medial and lateral side of a joint. For this reason, some biomechanics Marker Sets use medial markers as calibration markers. Calibration markers are used only when creating Skeletons but removed afterward for the actual capture. These calibration markers are highlighted in red from the 3D view when a Skeleton is first created.

Calibration Pose

A proper calibration posture is necessary because the pose of the created Skeleton will be calibrated from it.

T pose

The T-pose is commonly used as the reference pose in 3D animation to bind two characters or assets together. Motive uses this pose when creating Skeletons. A proper T-pose requires straight posture with back straight and head facing directly forward. Both arms are parallel to the ground, forming a “T” shape, with the palms facing downward. Both arms and legs must be straight, and both feet need to be aligned parallel to each other.

A pose

The A-pose is especially beneficial for subjects who have restricted mobility in one or both arms. Unlike the T-pose, arms are abducted at approximately 40 degrees from the midline of the body, creating an A-shape. There are three different types of A-pose: Palms down, palms forward, and elbows bent.

• Palms Down: Arms straight. Abducted, sideways, arms approximately 40 degrees, palms facing downwards.

• Palms forward: Arms straight. Abducted, sideways, arms approximately 40 degrees, palms facing forward. Be careful not to over rotate the arm.

• Elbows Bent: Similar to all other A-poses. arms approximately 40 degrees, bend elbows so that forearms point towards the front. Palms facing downwards, both forearms aligned.

Creating Skeletons

Skeleton Creation Steps

1. Select the calibration Pose you plan to use to define the Skeleton from the drop-down menu. This is set to the T-pose by default.

4. Enter a unique name for the skeleton. The skeleton name is included as a prefix in the label for each of the skeleton markers.

6. Click Create. Once the Skeleton model has been defined, confirm all Skeleton segments and assigned markers are located at the expected locations. If any of the Skeleton segments seem to be misaligned, delete and create the Skeleton again after adjusting the marker placements and the calibration pose.

Modifying Skeletons

Several changes can be made to Skeleton assets from the Modify tab of the Builder pane, or through the context menus available in the 3D Viewport or the Assets Pane.

Recalibrate a Skeleton

Skeleton assets can be recalibrated using the existing Skeleton information. Recalibration recreates the selected Skeleton using the same Skeleton Marker Set and refreshes expected marker locations on the assets.

There are several ways to recalibrate a Skeleton:

• From the Modify tab of the Builder pane.

• Select all of the associated Skeleton markers in the 3D Viewport, right-click and select Skeleton (1) --> Recalibrate from Selection.

• Right-click the skeleton in the Assets pane and select Skeleton (1) --> Recalibrate from Markers.

Marker Constraints

Right-click the skeleton in the asset pane and select Constraints --> Reset Constraints to Default to update the Skeleton markers with the default constraints template.

Add or Remove Constraints

Skeleton Marker Sets can be modified slightly by adding or removing markers to or from the template. Follow the below steps for adding/removing markers.

Add Marker Constraints

2. In the 3D Viewport, select the Skeleton segment that you are adding add the extra markers to.

3. CTRL + left-click on the marker that you wish to add to the skeleton.

5. You can also add Constraints from the Constraints pane.

6. Reconstruct and Auto-label the Take.

To Remove

2. [Optional] Under the advanced properties of the target Skeleton, enable the Marker to Constraint Lines property to view which markers are associated with different Skeleton bones.

4. Select the Skeleton segment to modify and the Marker Constraints you wish to dissociate.

Marker Sticks

A Marker stick connects two markers to create a visible line. Marker sticks define the shape of an asset, showing which markers connect to each other, such as knee to hip, and which don't, such as hand to foot. Skeleton Marker Sets include the placement of marker sticks.

Skeleton Properties

Export Assets

When asset definitions are exported to a MOTIVE user profile, the profile stores the marker arrangements calibrated in each asset, which can be imported into different takes without creating a new asset in Motive.

The user profile stores the spatial relationship of each marker to the others in the asset. Only the identical marker arrangement will be recognized and defined with the imported asset.

To export all of the assets in Live-mode or in the current TAKE file, go to File menu and selected Export Assets. You can also select the File menu → Export Profile option to export other software settings as well as the assets.

Relative Skeleton Joint Angles

Constraints XML: Customize Marker Labels, Colors, and Sticks

To export Skeleton constraints XML file

To import Skeleton constraints XML file

Overview

When using streamed Rigid Body data to animate a real-life replicated 3D model, it's critical that the Rigid Body's pivot point aligns with the location of the pivot point in the corresponding 3D model. If they are not aligned, the animated motion will not be in a 1:1 ratio to the actual motion.

This alignment is critical for real-time VR applications where real-life objects are 3D modeled and animated in the scene.

Live and Edit Modes

These steps can be completed in Live or Edit mode.

There are two modes for editing:

• Edit: Playback in standard Edit mode displays and streams the processed 3D data saved in the recorded Take. Changes made to settings and assets are not reflected in the Viewport until the Take is .

• Edit 2D: Playback in Edit 2D mode performs a live reconstruction of the 3D data, immediately reflecting changes made to settings or assets. These changes are displayed in real-time but are not saved into the recording until the Take is and saved. To playback in 2D mode, click the Edit button and select Edit 2D.

Aligning Rigid Body Pivot Point

There are two methods to align the pivot point of a rigid body. We recommend using the measurement probe method as it is the most accurate.

Measurement Probe

Step 1. Create a Rigid Body of the target object

Step 2. Create a measurement probe asset

You can purchase an OptiTrack probe or create your own.

Step 3. Collect data points to outline the silhouette

Step 4. Attach 3D model

After generating 3D data points using the probe, attach the game geometry (obj file) to the Rigid Body.

1. Select the Rigid Body in either the Devices pane or the 3D Viewport to show its properties in the Properties pane.

2. In the Visuals section, select Custom Model under the Geometry property. (Note: this is an Advanced setting.)

3. This will open the Attached Geometry field. Click the folder to the right of the field to browse to the location of your 3D model.

Step 5. Translate the pivot point

Step 6. Align to Geometry

1. With both the Rigid Body and the 3D model selected, open the Modify tab in the Builder pane.

2. In the Align to... section, select Geometry.

3. The pivot point for the Rigid Body will snap to align with the pivot point for the 3D model.

Reference Grayscale View

Use a reference camera when the option to use the probe method is not available.

1. Change the Video Type for one of the cameras to grayscale mode.

2. Right-click the camera and select Make Reference.

This page provides detailed instructions on camera system calibration and information about the .

Overview

Calibration is essential for high quality optical motion capture systems. During calibration, the system computes the position and orientation of each camera and number of distortions in captured images to construct a 3D capture volume in Motive. This is done by observing 2D images from multiple synchronized cameras and associating the position of known calibration markers from each camera through triangulation.

If there are any changes in a camera setup the system must be recalibrated to accommodate those changes. Additionally, calibration accuracy may naturally deteriorate over time due to ambient factors such as fluctuations in temperature. For this reason, we recommend recalibrating the system periodically.

General Steps in Calibration

1. Prepare and optimize the capture volume for setting up a motion capture system.

2. Apply masks to ignore existing reflections in the camera view.

3. Collect calibration samples through the wanding process.

4. Review the wanding result and apply calibration.

5. Set the ground plane to complete the system calibration.

Calibration Types

• Full: Calibrate all the cameras in the volume from scratch, discarding any prior known position of the camera group or lens distortion information. A Full calibration will also take the longest time to run.

• Refine: Adjusts slight changes in the calibration of the cameras based on prior calibrations. This will solve faster than a Full calibration. Use this only if the cameras have not moved significantly since they were last calibrated. A Refine calibration will allow minor modifications in camera position and orientation, which can occur naturally from the environment, such as due to mount expansion.

Starting a New Calibration

Preparing and Optimizing the Setup

• Cameras need to be appropriately placed and configured to fully cover the capture volume.

• Each camera must be mounted securely so that it remains stationary during capture.

• Motive's camera settings used for calibration should ideally remain unchanged throughout the capture. Re-calibration may be required if there are any significant modifications to the settings that influence the data acquisition, such as camera settings, gain settings, and Filter Switcher settings.

Masking

Before performing a system calibration, all extraneous reflections or unnecessary markers should be removed or covered so they are not seen by the cameras. When this isn't possible, extraneous reflections can be ignored by masking them in Motive.

Applying Masks

2. Check the corresponding camera view to identify where the reflection is coming from, and if possible, remove it from the capture volume or cover it for the calibration.

Wanding

The wanding process is Motive's core pipeline for collecting calibration samples. A calibration wand with preset markers is waved repeatedly throughout the volume, allowing all cameras to see the calibration markers and capture the sample data points from which Motive will compute their respective position and orientation in the 3D space.

Wand Samples

For best results, the following requirements should be met:

• At least two cameras must see all three of the calibration markers simultaneously.

• Cameras should see only calibration markers. If any other reflection or noise is detected during wanding the sample will not be collected and may affect the calibration results negatively. For this reason, the person doing the wanding should not be wearing anything reflective.

• The markers on the calibration wand must be in good quality. If the marker surface is damaged or scuffed, the system may struggle to collect wanding samples.

Wand Types

There are different types of calibration wands suited for different capture applications. In all cases, Motive recognizes the asymmetrical layout of the markers as a wand and applies the dimensions of the wand selected at the beginning of the wanding process in calculating the calibration.

Unless specified otherwise, the wands use retro-reflective markers placed in a line at specific distances. For optimal results, it is important to keep the calibration wand markers untouched and undistorted.

Wanding Steps

1. Confirm that masking was successful, and the volume is free of extraneous reflections. Return to the masking steps if necessary to mask any items that cannot be removed or covered.

2. To complete a full calibration, deselect any cameras that were selected during the previous steps so that no cameras are selected.

3. Set the Calibration Type. If you are calibrating a new capture volume, choose Full Calibration.

4. Under the Wand settings, specify the wand type you will use. Selecting the wrong wand type may result in scaling issues in Motive.

5. Double check the calibration setting. Once confirmed, press Start Wanding to start collecting wanding sample.

6. Bring your calibration wand into the capture volume and wave the wand gently across the entire volume. Slowly draw figure-eights repetitively with the wand to collect samples at varying orientations while covering as much space as possible for sufficient sampling.

PrimeX Series: LED Indicator ring

For Prime series cameras, the LED indicator ring displays the status of the wanding process.

• When wanding is initiated, the LED ring turns dark.

• When a camera detects all three markers on the calibration wand, part of the LED ring will glow blue to indicate that the camera is collecting samples. The location of the blue light will indicate the wand position in the respective camera view.

• As calibration samples are collected by each camera, all the lights in the ring will turn green to indicate enough samples have been collected.

• Cameras that do not have enough samples will begin to glow white as other cameras reach the minimum threshold to begin calibration. Check the 2D view to see where additional samples are needed.

• When all of the cameras emit a bright green light to indicate enough samples have been collected, the Start Calculating button will become active.

Calibration Results

Pess Start Calculating to calibrate. The length of time needed to calculate the calibration varies based on the number of cameras included in the system and the number of collected samples.

Click Show List to see the errors for each camera.

Calibration Result Report

• The result is determined by the mean error, resulting in the following ratings: Poor, Fair, Good, Great, Excellent, and Exceptional.

• If the results are acceptable, press Continue to apply the calibration. If not, press Cancel and repeat the wanding process.

• In general, if the results are anything less than Excellent, we recommend you adjust the camera settings and/or wanding techniques and try again.

Calibration Result

Ground Plane and Origin

The final step of the calibration process is setting the ground plane and origin for the coordinate system in Motive. This is done using a Calibration Square.

• Place the calibration square in the volume where you want the origin to be located, and the ground plane to be leveled.

• If using a standard OptiTrack calibration square, Motive will recognize it in the volume and display it as the detected device in the Calibration pane.

• Align the calibration square so that it references the desired axis orientation. Motive recognizes the longer leg on the calibration square as the positive z axis, and the shorter leg as the positive x axis. The positive y axis will automatically be directed upward in a right-hand coordinate system.

• Use the level indicator on the calibration square to ensure the orientation is horizontal to the ground. If any adjustment is needed, rotate the nob beneath the markers to adjust the balance of the calibration square.

• If needed, the ground plane can be adjusted later.

Custom Calibration Square

A custom calibration square can also be used to define the ground plane. All it takes to make a custom square is three markers that form a right-angle with one arm longer than the other, like the shape of the calibration square.

To use a custom calibration square, select Custom in the drop-down menu, enter the correct vertical offset and select the square's markers in the 3D Viewport before setting the ground plane.

Vertical offset

Motive accounts for the vertical offset when using a standard OptiTrack calibration square, setting the origin at the bottom corner of the calibration square rather than the center of the marker.

When using a custom calibration square, measure the distance between the center of the marker and the lowest tip at the vertex of the calibration square. Enter this value in the Vertical Offset field in the Calibration pane.

Set Origin with a Rigid Body

To have the most control of the location of of the global origin, including placing it at the location of a marker, we recommend setting the origin to the pivot point of a rigid body.

1. Create the Rigid Body.

4. In the Calibration pane, select Rigid Body for the Ground Plane. Motive will set the origin to the selected Rigid Body's pivot point.

Change Ground Plane Options

Ground Plane Refinement

The Ground Plane Refinement feature improves the leveling of the coordinate plane. This is useful when establishing a ground plane for a large volume, because the surface may not be perfectly uniform throughout the plane.

To use this feature, place several markers with a known radius on the ground, and adjust the vertical offset value to the corresponding radius. Select these markers in Motive and press Refine Ground Plane. This will adjust the leveling of the plane using the position data from each marker.

Translate or Rotate Ground Plane

To adjust the position and orientation of the global origin after the capture has been taken, use the capture volume translation and rotation tool.

To apply these changes to recorded Takes, you will need to reconstruct the 3D data from the recorded 2D data after the modification has been applied.

Scale Volume

To rescale the volume, place two markers a known distance apart. Enter the distance, select the two markers in the 3D Viewport, and click Scale Volume.

Calibration Files

Refining Calibration

Continuous Calibration

Enabling/Disabling Continuous Calibration

Offline Calibration

When capturing throughout a whole day, temperature fluctuations may degrade calibration quality and create the need to recalibrate the capture volume at different times of the day. However, repeating the entire calibration process can be tedious and time-consuming especially for a system with a large number of cameras.

Instead of repeating an entire full calibration, you can record Takes while wanding and takes with the calibration square in the volume and use those takes to re-calibrate in the post-processing. This saves calibration calculation time on the capture day because you can apply the calibration from the recorded wanding take in the post-processing instead. Offline calibration allows time to inspect the collected capture data, re-calibrating from a recorded Take only when signs of degraded calibration quality are seen in the captures.

Offline Calibration Steps

Capture wanding and ground plane Takes. At different times of the day, record wanding Takes that resemble the calibration wanding process. Also record corresponding ground plane Takes with the calibration square set in the volume to define the ground plane.

1. Open the Take to be recalibrated.

3. Browse to and select the wanding Take that was captured around the same time as the Take to be recalibrated.

4. From the Calibration pane, click New Calibration.

5. In Edit mode, click Start Wanding. Motive will import the wanding from the Take file selected in step 3 and display the results.

6. Click the Start Calculating button.

7. (Optional) Export the calibration results by selecting Export Camera Calibration from the File menu. The results will be saved as s .cal file.

8. Click Apply Results to accept the calibration.

9. Motive will move to the next step in the calibration process, setting the ground plane. If the ground plane is in a separate Take, then click Done and proceed to step 10. If the ground plane is in the calibration Take already loaded, then move to step 13.

10. From the Calibration pane, click Load Calibration...

11. Browse to and select the Ground Plane Take that was captured around the same time as the Take to be recalibrated.

12. From the Calibration pane, click Change Ground Plane.

14. Motive will display a warning that any 3D data in the take will need to be reconstructed and auto-labeled. Click Continue to proceed.

Partial Calibration

Partial calibration updates the calibration for selected cameras in a system by updating their position relative to the already calibrated cameras. Use this feature:

• In a high camera count systems where only a few cameras need to be adjusted.

• To recalibrate the volume without resetting the ground plane. Motive will retain the position of the ground plane from the unselected cameras.

• To add new cameras into a volume that has already been calibrated.

Partial Calibration Steps

1. Select the camera(s) to be recalibrated in the Cameras Viewport.

3. Select the Calibration Type. In most cases you will want to set this to Full, such as when adding new cameras to a volume or adjusting several cameras. When the camera moved slightly, Refine works as well.

4. Specify the wand type.

5. From the Calibration Pane, click Start Wanding. A warning message will ask you to confirm that only the selected cameras will be calibrated. Click continue.

6. Wand in front of the selected cameras and at least one unselected camera. This will allow Motive to align the cameras being calibrated with the rest of the cameras in the system.

7. When you have collected sufficient wand samples, click Calculate.

9. Click Apply. The selected cameras will now be calibrated to the rest of the cameras in the system.

Notes:

• This feature requires the unselected cameras to be in a good calibration state. If the unselected cameras are out of calibration, using this feature will return bad calibration results.

• Partial calibration does not update the calibration of the unselected cameras. However, the calibration report that Motive provides does include all cameras that received samples, selected or unselected.

Camera Gizmo

Cameras can be modified using the gizmo tool if the Settings Window > General > Calibration > "Editable in 3D View" property is enabled. Without this property turned on the gizmo tool will not activate when a camera is selected to avoid accidentally changing a calibration. The process for using the gizmo tool to fix a misaligned camera is as follows:

1. Select the camera you wish to fix, then view from that camera (Hotkey: 3).

2. Select either the Translate or Rotate gizmo tool (Hotkey: W or E).

3. Use the red diamond visual to align the unlabeled rays roughly onto their associated markers.

4. Right click and choose Correct Camera Position/Orientation. This will perform a calculation to place the camera more accurately.

Active LED Calibration

The OptiTrack motion capture system is designed to track retro-reflective markers. However, active LED markers can also be tracked with appropriate customization. If you wish to use Active LED markers for capture, the system will ideally need to be calibrated using an active LED wand. Please contact us for more details regarding Active LED tracking.

Q & A

Troubleshooting

General Questions

This page provides detailed information on the continuous calibration feature, which can be enabled from the . For additional Continuous Calibration features, please see the page.

Overview

The Continuous Calibration feature ensures your system always remains optimally calibrated, requiring no user intervention to maintain the tracking quality. It uses highly sophisticated algorithms to evaluate the quality of the calibration and the triangulated marker positions. Whenever the tracking accuracy degrades, Motive will automatically detect and update the calibration to provide the most globally optimized tracking system.

Key Features

• Ease of use. This feature provides much easier user experience because the capture volume will not have to be re-calibrated as often, which will save a lot of time. You can simply enable this feature and have Motive maintain the calibration quality.

• Optimal tracking quality. Always maintains the best tracking solution for live camera systems. This ensures that your captured sessions retain the highest quality calibration. If the system receives inadequate information from the environment, the calibration with not update and your system never degrades based on sporadic or spurious data. A moderate increase in the number of real optical tracking markers in the volume and an increase in camera overlap improves the likelihood of a higher quality update.

• Works with all camera types. Continuous calibration works with all OptiTrack camera models.

Requirements

For continuous calibration to work as expected, the following criteria must be met:

• Markers Must Be Tracked. Continuous calibration looks at tracked reconstructions to assess and update the calibration. Therefore, at least some number of markers must be tracked within the volume.

• Majority of Cameras Must See Markers. A majority of cameras in a volume needs to receive some tracking data within a portion of their field of view in order to initiate the calibration process. Because of this, traditional perimeter camera systems typically work the best. Each camera should additionally see at least 4 markers for optimal calibration. If not all the cameras see the markers at the same time, anchor markers will need to be set up to improve the calibration updates.

How to Use

Anchor Markers

Anchor markers further improve the continuous calibration. When properly configured, anchor markers establish a known point-of-reference for continuous calibration updates, especially on systems that consists of multiple sets of cameras that are separated into different tracking areas, by obstructions or walls, without camera view overlap. Anchor markers provide extra assurance that the global origin will not shift during each update, which the continuous calibration feature checks for as well.

Active Anchor Markers

Active markers are best to use for anchors due to their unique active IDs, which improve accuracy, remove ambiguity, and enhance continuous calibration all around.

• Cameras will always correctly identify an active marker even when no other markers are visible or after an occlusion. This helps the system calibrate more frequently, and to quickly adjust after more significant disturbances.

• Anchor markers are critical to maintaining a single calibration throughout a partitioned volume. Active markers ensure that the cameras can correctly identify each anchor marker location.

• Active markers allow bumped cameras to update faster and more accurately, and to recover from larger disturbances than passive markers.

Anchor Marker Setup

Follow the steps below for setting up the anchor marker in Motive:

Adding Anchor Markers in Motive

2. Place any number of markers in the volume to assign them as the anchor markers.

3. Make sure these markers are securely fixed in place within the volume. It's important that the distances between these markers do not change throughout the continuous calibration updates.

5. In the 3D viewport, select the markers that are going to be assigned as anchors.

6. Click on Add to add the selected markers as anchor markers.

7. Once markers are added as anchor markers, magenta spheres will appear around the markers indicating the anchors have been set.

8. Add more anchors as needed, again, it's important that these anchor markers do not move throughout the tracking. Also when the anchor markers need to be reset, whether if the marker was displaced, you can clear the anchor markers and reassign them.

Camera Partitions

For multi-room setups, it is useful to group cameras into partitions. This allows for Continuous Calibration to run in each individual room without the need for camera view overlap.

Properties Pane: Camera

From the Properties pane of a camera you can assign a Partition ID from the advanced settings.

You'll want to assign all the cameras in the same room the same Partition ID. Once assigned these cameras will all contribute to Continuous Calibration for their particular space. This will help ensure the accuracy of Continuous Calibration for each individual space that is a part of the whole system.

Editing Camera Positions with Gizmo Tool

Overview

Within the Info Tab, you'll find additional Continuous Calibration features in order to update your Calibrations in real-time.

Below you'll find the steps for each of these features.

Camera Samples

Camera Samples is a visual aid that shows which cameras may need more marker samples or a better distribution of marker samples.

More Markers

If a camera appears under More Markers:

1. Select the camera under More Markers.

2. Navigate to the 2D Viewport and from the top left dropdown select "From Camera 'x'".

3. This will show the camera's field of view and any markers that it can see within the cyan box.

4. Add additional markers within the camera's view until the camera button is removed from More Markers.

Better Distribution

You may have enough markers so that there are no cameras listed under More Markers, but still see cameras under Better Distribution.

1. Select a camera listed under Better Distribution.

2. Navigate to the 2D Viewport and from the top left dropdown select "From Camera 'x'".

3. This will show the camera's field of view and any markers that it can see within the cyan box.

4. Add additional markers that are more evenly distributed within the camera's view.

Anchor Markers

Anchor markers can be set up in Motive to further improve continuous calibration. When properly configured, anchor markers improve continuous calibration updates, especially on systems that consists of multiple sets of cameras that are separated into different tracking areas, by obstructions or walls, without camera view overlap. It also provides extra assurance that the global origin will not shift during each update, although the continuous calibration feature itself already checks for this.

The Anchor Markers section allows you to add/remove and import/export Anchor markers. It also shows the mean error under the Distance column for each individual Anchor marker and the overall in the top right in millimeters.

Partitions

For multi-room setups, it is useful to group cameras into partitions. This allows for Continuous Calibration to run in each individual room without the need for camera view overlap.

The Partitions section directly corresponds with Partitions created in the Properties pane for each individual camera. This section displays the status of Continuous Calibration for each partition.

Partition Table Columns

No.

This is the Partition ID assigned via the camera's Properties pane. By default this value is 1.

Status

• Idle - Continuous Calibration is either turned off or there are not enough markers for Continuous Calibration to begin sampling.

• Sampling - Continuous Calibration is collecting marker samples.

• Evaluating - Continuous Calibration is determining if the latest samples are better than the previous and will update if necessary.

• Processing - Processing will occur when an update is processing.

Last Validated

Last Validated will update its timestamp to 0h 0m 0s when the samples have been collected and the calibration solution was not deemed to be better than the solution already in place.

Last Updated

Last Updated will update its timestamp to 0h 0m 0s when good samples were collected and the calibration solution was deemed better than the solution in place.

Error

This is the mean ray error for each partition in millimeters. The overall mean ray error will be displayed in the top right corner of the section.

Anchors

This column denotes the number of Anchor markers that are visible within a partition.

Partitions Settings

The Partitions settings can be updated to custom values based on an individual user's needs. This ensures that the user is alerted when Continuous Calibration is not validating or updated. When these values are changed the Partitions section rows will turn magenta if they do not meet the standards of Maximum Error and/or Maximum Last Updated.

Maximum Error

This setting can be changed to any positive decimal. If the ray error for a Partition exceeds this value, the text in the Partition's row will change to magenta and the icon on the top right of the Partition section will display a red circle with an 'x'.

Maximum Last Updated

Maximum Last Updated dictates how long Continuous Calibration can go without an update before the user is alerted (by a magenta text and a red circle with an 'x' icon) that Continuous Calibration has not been updated.

Bumped Cameras

The Bumped Cameras features corrects a camera's position in Motive if it is physically bumped in the real 3D space.

Quick Start Guide

2. Enable Bumped Cameras from the Bumped Cameras Settings:

   1. Select Camera Samples for Mode.

   2. Select either Anchor Markers, Active Markers, or Both from Marker Type.

3. Bumped Cameras is now able to correct physical camera movement without needing a full Calibration.

To see the results of Bumped Cameras steps above you can do the following:

1. Select the camera's view you intend to physically move in the 2D Camera Viewport.

2. Make sure Tracked and Untracked Rays are visible from the 'eye' icon in the 2D Camera Viewport.

3. Physically move the camera so that the markers appear with a red diamond around them (untracked).

4. Wait a few seconds and notice the camera's view shift to correct in the 2D Camera Viewport.

5. The red diamonds should now be green.

Bumped Cameras Settings

Mode

• Disabled - When Mode is set to Disabled, Bumped Camera correction will not apply.

• Camera Samples - When Mode is set to Camera Samples, Bumped Camera correction will correct based on the Camera Samples data. If Camera Samples is populated with cameras this will trigger Bumped Cameras to correct any cameras that may have moved. If a camera has NOT moved, this camera will remain idle in the Bumped Camera section until Camera Samples is clear of needed samples or distribution.

• Selected Cameras - When Mode is set to Selected Cameras, this will ONLY correct the camera that is selected by the user from either the Devices, 3D or 2D viewport, or Camera Samples.

Marker Type

• Anchor Markers - ONLY Anchor Markers will be used to collect data for Bumped Cameras to correct a camera's position.

• Active Markers - ONLY Active Markers will be used to collect data for Bumped Cameras to correct a camera's position.

• Anchor and Active - BOTH Anchor and Active Markers will be used to collect data for Bumped Cameras to correct a camera's position.

Max Camera Count

If you only wish to have a few cameras corrected you can lower the count of the Max Camera Count. By default this is set to 20.

In Motive, Rigid Body assets are used for tracking rigid, unmalleable, objects. A set of markers is securely attached to tracked objects, and respective placement information is used to identify the object and report 6 Degree of Freedom (6DoF) data. Thus, it's important that the distances between placed markers stay the same throughout the range of motion. Either passive retro-reflective markers or active LED markers can be used to define and track a Rigid Body.

Rigid Body Marker Placement

A Rigid Body in Motive is a collection of three or more markers on an object that are interconnected to each other with an assumption that the tracked object is unmalleable. More specifically, Motive assumes the spatial relationship among the attached markers remains unchanged and the marker-to-marker distance does not deviate beyond the allowable tolerance defined under the corresponding Rigid Body properties. Otherwise, involved markers may become . Cover any reflective surfaces on the Rigid Body with non-reflective materials and attach the markers on the exterior of the Rigid Body where cameras can easily capture them.

Number of Markers

In a 3D space, a minimum of three coordinates are required for defining a plane using vector relationships. Likewise, at least three markers are required to define a Rigid Body in Motive. Whenever possible, it is best to use 4 or more markers to create a Rigid Body. Additional markers provide more 3D coordinates for computing positions and orientations of a rigid body, making overall tracking more stable and less vulnerable to marker occlusions. When any of markers are occluded, Motive can reference other visible markers to solve for the missing data and compute the position and orientation of the rigid body.

However, placing too many markers on one Rigid Body is not recommended. When too many markers are placed in close vicinity, markers may overlap on the camera view, and Motive may not resolve individual reflections. This can increase the likelihood of label-swaps during capture. Securely place a sufficient number of markers (usually less than 10), just enough to cover the main frame of the Rigid Body.

Asymmetrical Marker Placements

Within a Rigid Body asset, the markers should be placed asymmetrically because this provides a clear distinction of orientations. Avoid placing the markers in symmetrical shapes such as squares, isosceles, or equilateral triangles. Symmetrical arrangements make asset identification difficult and may cause the Rigid Body assets to flip during capture.

Unique Marker Placements

When tracking multiple objects using passive markers, it is beneficial to create unique Rigid Body assets in Motive. Specifically, you need to place retroreflective markers in a distinctive arrangement between each object, which will allow Motive to more clearly identify the markers on each Rigid Body throughout capture. In other words, their unique, non-congruent, arrangements work as distinctive identification flags among multiple assets in Motive. This not only reduces processing loads for the Rigid Body solver, but it also improves the tracking stability. Not having unique Rigid Bodies could lead to labeling errors especially when tracking several assets with similar size and shape.

What Makes Rigid Bodies Unique?

The key idea of creating unique Rigid Body is to avoid geometrical congruency within multiple Rigid Bodies in Motive.

• Unique Marker Arrangement. Each Rigid Body must have a unique, non-congruent, marker placement creating a unique shape when the markers are interconnected.

• Unique Marker-to-Marker Distances. When tracking several objects, introducing unique shapes could be difficult. Another solution is to vary Marker-to-marker distances. This will create similar shapes with varying sizes and make them distinctive from the others.

• Unique Marker Counts Adding extra markers is another method of introducing uniqueness. Extra markers will not only make the Rigid Bodies more distinctive, but they will also provide more options for varying the arrangements to avoid the congruency.

What Happens When Rigid Bodies Are Not Unique?

Having multiple non-unique Rigid Bodies may lead to mislabeling errors. However, in Motive, non-unique Rigid Bodies can also be tracked fairly well as long as the non-unique Rigid Bodies are continuously tracked throughout capture. Motive can refer to the trajectory history to identify and associate corresponding Rigid Bodies within different frames.

Tracking Multiple Rigid Bodies

Depending on the object, there could be limitations on marker placements and number of variations of unique placements that could be achieved. The following list provides sample methods for varying unique arrangements when tracking multiple Rigid Bodies.

• Create Distinctive 2D Arrangements. Use distinctive, non-congruent, marker arrangements as the starting point for producing multiple variations, as shown in the examples above.

• Vary marker height. Use marker bases or posts of different heights to introduce variations in elevation to create additional unique arrangements.

• Vary Maximum Marker to Marker Distance. Increase or decrease the overall size of the marker arrangements.

• Add Two (or more) Markers Lastly, if an additional variation is needed, add extra markers. We recommended adding at least two extra markers in case any become occluded.

Creating a Rigid Body

In creating a Rigid Body asset, a set of markers attached to a rigid object are grouped and auto-labeled as a Rigid Body. This Rigid Body definition can be used in multiple takes to continuously auto-label the same asset markers. Motive recognizes the unique spatial relationship in the marker arrangement and automatically labels each marker to track the Rigid Body.

Steps to Create a Rigid Body

Step 3: Click Create to define a Rigid Body asset from the selected markers.

You can also create a Rigid Body by doing the following actions while the markers are selected:

• Perspective View (3D viewport): Right-click the selection in the perspective view to access the context menu. Under the Markers section, click Create Rigid Body.

• Hotkey: While the markers are selected, use the create Rigid Body hotkey (Default: Ctrl +T).

Rigid Body Properties

Default Properties

Modifying Properties

Add or Remove Markers

There are multiple ways to add or remove markers on a Rigid Body.

• • Select the Modify tab.

Tracking a Rigid Body

Real-time Information

Adjusting a Rigid Body Pivot Point

The location of a pivot point can be adjusted by assigning it to a marker or by translating along the Rigid Body axis (x, y, z). For the most accurate pivot point location, attach a marker at the desired pivot location, set the pivot point to the marker, and apply the translation for precise adjustments.

Post-Processing Edit Modes

Edit Mode is used for playback of captured Take files. In this mode, you can playback and stream recorded data and complete post-processing tasks. The Cameras View displays the recorded 2D data while the 3D Viewport represents either recorded or real-time processed data, as described below.

There are two modes for editing:

Default Orientation

Location: Translate Pivot Point

Use the Location tool to enter the amount of translation (in mm) to apply along the (x, y, z) coordinates then click Apply. Clicking Apply again will add to the existing translation and can be used to fine-tune the adjustment of the bone.

Click Clear to reset the fields to 0mm.

Reset will position the pivot point at the geometric center of the Rigid Body according to its marker positions.

Orientation: Rotate Pivot Point

Use this tool to apply rotation to the local coordinate system of a selected Rigid Body. You can also reset the orientation to re-align the Rigid Body coordinate axis and the global axis. When resetting the orientation, the Rigid Body must be tracked in the scene.

Reset Pivot Point: Context Menu

In addition to the Reset buttons on the Builder pane, you can right-click a selected rigid body to open the Asset(s) context menu. Select Bones (#) --> Reset Location.

Align to Geometry

The Align to Geometry feature provides an option to align the pivot of a rigid body to a geometry offset. Motive includes several standard geometric objects that can be used, as well as the ability to import custom objects created in other applications. This allows for consistency between Motive and external rendering programs such as Unreal Engine and Unity.

Scroll to the Visuals section of the asset's properties. Under Geometry, select the object type from the list.

To import your own object, select Custom Model. This will open the Attached Geometry field. Click on the file folder icon to select the .obj or .fbx file to import into Motive.

Align to Camera

To align an asset to a specific camera, select both the asset and the camera in the 3D ViewPort. Click Camera in the Align to... field in the Modify tab.

Align to Rigid Body

To align an asset to an existing Rigid Body, you must be in 2D edit mode. Click the Edit button at the bottom left and select EDIT 2D from the menu.

Spherical Bone Placement

This feature is useful when tracking a spherical object (e.g., a ball). Motive will assume all of the markers on the selected Rigid Body are placed on the surface of a spherical object and will calculate and re-position the pivot point accordingly. Simply select a Rigid Body in Motive, open the Builder pane to edit Rigid Body definitions, and then click Apply to place the pivot point at the center of the spherical object.

Refine

The Rigid Body refinement tool improves the accuracy of the Rigid Body calculation in Motive. When a Rigid Body asset is initially created, Motive references only a single frame to define it. The Rigid Body refinement tool allows Motive to collect additional samples, achieving more accurate tracking results by improving the calculation of expected marker locations of the Rigid Body as well as the position and orientation of the Rigid Body itself.

Steps

2. Click the Modify tab.

3. Select the Rigid Body to be refined in the Asset pane.

4. 1. In the Refine section of the Modify tab of the Builder pane, click Start...

   2. Slowly rotate the Rigid Body to collect samples at different orientations until the progress bar is full.

5. You can also refine the asset in Edit mode. Motive will automatically replay the current take file to complete the refinement process.

The Gizmo Tools

• Select Tool (Hotkey: Q): The Default option. Used for selecting objects in the Viewport. Return to this mode when you are done using the Gizmo tools.

• Translate Tool (Hotkey: W): Translate tool for moving the Rigid Body pivot point.

• Rotate Tool (Hotkey: E): Rotate tool for reorienting the Rigid Body coordinate axis.

• Scale Tool (Hotkey: R): Scale tool for resizing the Rigid Body pivot point.

Rigid Body Tracking Data Output

Rigid Body tracking data can be exported or streamed to client applications in real-time:

Additional Features

Hide Markers for Disabled Assets

You can disable assets and hide their associated markers once you are finished labeling and editing them to better focus on the remaining unedited assets.

To Hide Markers:

• Select Markers > Hide for Disabled Assets.

Export Asset Definitions

When an asset definition is exported to a user profile, Motive stores marker arrangements calibrated to the asset, which allows the asset to be imported into different takes without being rebuilt each time in Motive.

Profile files specifically store the spatial relationship of each marker. Only the identical marker arrangements will be recognized and defined with the imported asset.

To export all of the assets in Live or in the current TAKE file, go to the File menu → Export Assets.

You can also select Export Profile from the File menu to export other software settings, in addition to the assets.

Quick Start Guide

Trained Markersets allow you to create Assets from any object that is not a Rigid Body or a pre-defined Skeleton. This allows you to track anything from a jump rope, to a dog, to a flag, to anything in between.

Please follow the steps below to get started.

Auto-Generate Asset

• Attach an adequate number of markers to your flexible object. This is highly dependent on the object but should cover at least the outline and any internal flex points. e.g., if it's a mat, the mat should have markers along the edges as well as dispersed markers in the middle in an asymmetrical pattern. If it's an animal or something that has real-life bones, try to add markers on either side of any joints just like you see on the Skeleton marker sets.

• Record the movements you want of the object, trying to get as much of the full range of motion as possible.

• In Edit mode, select the markers attached to the object.

• Right-click and select Create Markerset.

• Right-click the newly created asset and select Training -> Auto-Generate Asset.

Adding Bones

To add Bones from the 3D viewport:

1. First make sure the Markerset is selected in the Assets pane, then hold down CTRL while selecting the markers from which you wish to make a bone.

2. Right click on one of the markers and select Bone(s) -> Add From Marker(s).

Once you are finished adding the necessary bones you can create Bone Chains to connect bones:

1. Select at least 1 bone (if you have multiple selected make sure the one you select first is the one you wish to make the first 'parent' bone then any subsequent children/parent bones should follow).

2. Right click in 3D viewport and select Bone(s) -> Add Bone Chain.
3. Solve your Markerset: right click on asset in asset pane and select Solve. You can now export, or stream, or do whatever else you'd like in Edit.

4. If you would like your Asset to be available in Live, simply right click on the Markerset in the Assets pane and select Copy Asset to Live.

5. And voilà, you have a Markerset you can track and record in Live.

Training Options

Auto-Generate Asset

This adds marker training and Auto-Generates Marker Sticks. This function only needs to be performed once after a Markerset has been created.

Add Marker Training

Add Marker Training goes through and adds a learned model of the Markerset. It's best to train the Markerset based on a full Range of Motion of the object you would like to track. This means moving the object to the limits of how it can move for one take, then labeling that take as well as you can, then running this training method on it.

Remove Marker Training

This removes any marker training that was added either by Auto-Generate Asset or Add Marker Training. This is useful if you changed labels and wanted to reapply new marker training based on the new labels.

Auto-Generate Bones

This automatically generates bones at flex points. This is why recording a full range of motion of your object is important so these bones can be added correctly.

Refine Bone Positions

This applies another round of Marker Training and refines Bone positions based on new training information.

Refine Constraints Positions

This applies another round of Marker Training and refines Constraint positions based on new training information.

3D View Context Menu Bone Options

Add from Marker(s)

This is how you can create Bones manually from selected markers.

Remove

This removes the Bone from the Markerset and 3D viewport.

Add Bone Chain

This adds a parent/child relationship to bones.

Unparent Bone(s)

This removes the Bone Chain between bones.

Reroot Bones

When a child bone is selected, you can select Reroot Bones to make a child bone the parent. i.e. Bone 002 is a child of Bone 001 and Bone 001 (the root bone) is a child to Markerset 001. After selecting Bone 002 and Reroot bones, Bone 002 is now the parent to Bone 001 and the child to Markerset 001.

Align to Camera

This will align the selected Bone to a selected camera.

Align to Other Bone

This will align the selected Bone to another selected Bone.

Reset Location

If the Bone position was altered by either the Gizmo Tool or by Align to Camera/Other Bone, you can reset its default position with Reset Location.

Labeling Pane in Motive The Edit Tools in Motive enables users to post-process tracking errors from recorded capture data. There are multiple editing methods available, and you need to clearly understand them in order to properly fix errors in captured trajectories. Tracking errors are sometimes inevitable due to the nature of marker-based motion capture systems. Thus, understanding the functionality of the editing tools is essential. Before getting into details, note that the post-editing of the motion capture data often takes a lot of time and effort. All captured frames must be examined precisely and corrections must be made for each error discovered. Furthermore, some of the editing tools implement mathematical modifications to marker trajectories, and these tools may introduce discrepancies if misused. For these reasons, we recommend optimizing the capture setup so that tracking errors are prevented in the first place.

Common tracking errors include marker occlusions and labeling errors. Labeling errors include unlabeled markers, mislabeled markers, and label swaps. Fortunately, label errors can be corrected simply by reassigning proper labels to markers. Markers may be hindered from camera views during capture. In this case, the markers will not be reconstructed into 3D space and introduce a gap in the trajectory, which are referred to as marker occlusions. Marker occlusions are critical because the trajectory data is not collected at all, and retaking the capture could be necessary if the missing marker is significant to the application. For these occluded markers, Edit Tools also provide interpolation pipelines to model the occluded trajectory using other captured data points. Read through this page to understand each of data editing methods in detail.

Steps in Editing

General Steps

1. Skim through the overall frames in a Take to get an idea of which frames and markers need to be cleaned up.

2. Refer to the Labels pane and inspect gap percentages in each marker.

3. Select a marker that is often occluded or misplaced.

4. Look through the frames in the Graph pane, and inspect the gaps in the trajectory.

5. For each gap in frames, look for an unlabeled marker at the expected location near the solved marker position. Re-assign the proper marker label if the unlabeled marker exists.

6. Use Trim Tails feature to trim both ends of the trajectory in each gap. It trims off a few frames adjacent to the gap where tracking errors might exist. This prepares occluded trajectories for Gap Filling.

7. Find the gaps to be filled, and use the Fill Gaps feature to model the estimated trajectories for occluded markers.

8. Re-Solve assets to update the solve from the edited marker data

Deleting Frames

In some cases, you may wish to delete 3D data for certain markers in a Take file. For example, you may wish to delete corrupt 3D reconstructions or trim out erroneous movements from the 3D data to improve the data quality. In the Edit mode, reconstructed 3D markers can be deleted for selected range of frames. To delete a 3D marker, first select 3D markers that you wish to delete, and press the Delete key, and they will be completely erased from the 3D data. If you wish to delete 3D markers for a specific frame range, open the Graph Pane and select the frame ranges that you wish to delete the markers from, and press the Delete key. The 3D trajectory for the selected markers will be erased for the highlighted frame range.

Note: Deleted 3D data can be recovered by reconstructing and auto-labeling new 3D data from recorded 2D data.

Trimming Captured Takes

The trimming feature can be used to crop a specific frame range from a Take. For each round of trim, a copied version of the Take will be automatically achieved and backed up into a separate session folder.

Steps for trimming a Take

1) Determine a frame range that you wish to extract.

2) Set the working range (also called as the view range) on the Graph View pane. All other frames outside of this range will be trimmed out. You can set the working range through the following approaches:

• Specify the starting frame and ending frame from the navigation bar on the Graph Pane.

3) After zooming into the desired frame range, click Edit > Trim Current Range to trim out the unnecessary frames.

4) A dialog box will pop up asking to confirm the data removal. If you wish to reset the frame numbers upon trimming the take, select the corresponding check box on the pop-up dialog.

Labeling Errors

The first step in the post-processing is to check for labeling errors. Labels can be lost or mislabeled to irrelevant markers either momentarily or entirely during capture. Especially when the marker placement is not optimized or when there are extraneous reflections, labeling errors may occur. As mentioned in other pages, marker labels are vital when tracking a set of markers, because each label affects how the overall set is represented. Examine through the recorded capture and spot the labeling errors from the perspective view, or by checking the trajectories on the Graph pane for suspicious markers. Use the Labels pane or the Tracks View mode from the Graph pane to monitor unlabeled markers in the Take.

When a marker is unlabeled momentarily, the color of tracked marker switches between white (labeled) and orange (unlabeled) by the default color setting. Mislabeled markers may have large gaps and result in a crooked model and trajectory spikes. First, explore captured frames and find where the label has been misplaced. As long as the target markers are visible, this error can easily be fixed by reassigning the correct labels. Note that this method is preferred over editing tools because it conserves the actual data and avoids approximation.

Read more about labeling markers from the Labeling page.

Edit Tools

The Edit Tools provide functionality to modify and clean-up 3D trajectory data after a capture has been taken. multiple post-processing methods are featured in the Edit Tools for different purposes: Trim Tails, Fill Gaps, Smooth, and Swap Fix. The Trim Tails method is used to remove data points in few frames before and after a gap. The Fill Gaps method calculates the missing marker trajectory using interpolation methods. The Smoothing method filters out unwanted noise in the trajectory signal. Finally, the Swapping method switches marker labels for two selected markers. Remember that modifying data using Edit Tools changes the raw trajectories, and an overuse of Edit Tools is not recommended. Read through each method and familiarize yourself with the Editing Tools. Note that you can undo and redo all changes made using Edit Tools.

Tails

The Tails method trims, or removes, a few data points before and after a gap. Whenever there is a gap in a marker trajectory, slight tracking distortions may be present on each end. For this reason, it is usually beneficial to trim off a small segment (~3 frames) of data. Also, if these distortions are ignored, they may interfere with other editing tools which rely on existing data points. Before trimming trajectory tails, check all gaps to see if the tracking data is distorted. After all, it is better to preserve the raw tracking data as long as they are relevant. Set the appropriate trim settings, and trim out the trajectory on selected or all frame. Each gap must satisfy the gap size threshold value for it to be considered for trimming. Each trajectory segment also needs to satisfy the minimum segment size, otherwise, it will be considered as a gap. Finally, the Trim Size value will determine how many leading and trailing trajectory frames are removed from a gap.

Smart Trim

The Smart Trim feature automatically sets the trimming size based on trajectory spikes near the existing gap. It is often not needed to delete numerous data points before or after a gap, but there are some cases where it's useful to delete more data points than others. This feature determines whether each end of the gap is suspicious with errors, and deletes an appropriate number of frames accordingly. Smart Trim feature will not trim more frames than the defined Leading and Trailing value.

Gaps

Gap filling is the primary method in the data editing pipeline, and this feature is used to remodel the trajectory gaps with interpolated marker positions. This is used to accommodate the occluded markers in the capture. This function runs mathematical modeling to interpolate the occluded marker positions from either the existing trajectories or other markers in the asset. Note that interpolating a large gap is not recommended because approximating too many data points may lead to data inaccuracy.

New to Motive 3.0; For Skeletons and Rigid Bodies only Model Asset Markers can be used to fill individual frames where the marker has been occluded. Model Asset markers must be first enabled on the Properties Pane when the desired asset is selected and then they must be enabled for selection in the Viewport. Now when frames are encountered where the marker is lost from camera view, select the associated Model Asset Marker in the 3D view; right click for the context menu and select 'Set Key'.

First of all, set the Max. Gap Size value and define the maximum frame length for an occlusion to be considered as a gap. If a gap size has a longer frame length, it will not be affected by the filling mechanism. Set a reasonable maximum gap size for the capture after looking through the occluded trajectories. In order to quickly navigate through the trajectory graphs on the Graph Pane for missing data, use the Find Gap features (Find Previous and Find Next) and automatically select a gap frame region so the data could be interpolated. Then, apply the Fill Gaps feature while the gap region is selected. Various interpolation options are available in the setting including Constant, Linear, Cubic, Pattern-based, and Model-based.

Interpolation options

There are four different interpolation options offered in Edit Tools: constant, linear, cubic and pattern-based. First three interpolation methods (constant, linear, and cubic) look at the single marker trajectory and attempt to estimate the marker position using the data points before and after the gap. In other words, they attempt to model the gap via applying different degrees of polynomial interpolations. The other two interpolation options (pattern-based and model-based) reference visible markers and models to the estimate occluded marker position.

Constant

Applies zero-degree approximation, assumes that the marker position is stationary and remains the same until the next corresponding label is found.

Linear

Applies first-degree approximation, assuming that the motion is linear, to fill the missing data. Only use this when you are sure that the marker is moving at linear motion.

Cubic

Applies third-degree polynomial interpolation, cubic spline, to fill the missing data in the trajectory.

Pattern based

This refers to trajectories of selected reference markers and assumes the target marker moves along in a similar pattern. The Fill Target marker is specified from the drop-down menu under the Fill Gaps tool. When multiple markers are selected, a Rigid Body relationship is established among them, and the relationship is used to fill the trajectory gaps of the selected Fill Target marker as if they were all attached to a same Rigid Body. The following list is the general workflow for using the Pattern Based interpolation:

1. Select both reference markers and the target marker to fill.

2. Examine the trajectory of the target marker from the Graph Pane: Size, range, and a number of gaps.

3. Set an appropriate Max. Gap Size limit.

4. Select the Pattern Based interpolation option.

5. Specify the Fill Target marker in the drop-down menu.

6. When interpolating for only a specific section of the capture, select the range of frames from Graph pane.

7. Click the Fill Selected/Fill All/Fill Everything.

Curves

The curves tool applies a noise filter (low-pass Butterworth, 4th degree) to trajectory data, and this modifies the marker trajectory smoother. This is a bi-directional filter that does not introduce phase shifts. Using this tool, any vibrating or fluttering movements are filtered out. First, set the cutoff frequency for the filter and define how strongly your data will be smoothed. When the cutoff frequency is set high, only high-frequency signals are filtered. When the cutoff frequency is low, trajectory signals at a lower frequency range will also be filtered. In other words, a low cutoff frequency setting will smooth most of the transitioning trajectories, whereas high cutoff frequency setting will smooth only the fluttering trajectories. High-frequency data are present during sharp transitions, and this can also be introduced by signal noise. Commonly used ranges for Filter Cutoff Frequency are between 7 Hz to 12 Hz, but you may want to adjust the value higher for fast and sharp motions to avoid softening motion transitions need to stay sharp.\

Fragments

This tool is used for quickly deleting any marker trajectories that exist only for a few frames. Markers that appear only momentarily are likely happening due to noise in the data. If you wish to clean up these short-lived trajectories to further clean up the data, the fragments tool can be used. You will just need to set the minimum frame percentage under the settings. Then, when you click delete, individual marker trajectories that are shorter than the percentage defined will be deleted.

Swaps

In some cases, marker labels may be swapped during capture. Swapped labels can result in erratic orientation changes, or crooked Skeletons, but they can be corrected by re-labeling the markers. The Swap Fix feature in the Edit Tools can be used to correct obvious swaps that persist through the capture. Select two markers that have their labels swapped, and select the frame range that you wish to edit. Find Previous and Find Next buttons allow you to navigate to the frame where their position have been changed. If a frame range is not specified, the change will be applied from current frame forward. Finally, switch the marker labels by clicking on the Apply Swap button. As long as both labels are present in the frame and only correction needed is to change the labels, the Swap Fix tool could be utilized to make corrections.

Solve

Overview

Camera data captured in Motive can be streamed live to other applications or recorded into the Take file (.tak) file format. Once recorded, data can be exported from the Take. The Take can also be edited and streamed into other applications.

A Take file includes:

• 2D Motion Capture data.

• 3D Solved data.

• Reference video, if included during the capture.

Preparing to Record

Before you begin recording, make sure the following items are completed:

• The OptiTrack camera system is properly installed, with each camera focused and aimed for the best capture experience. Please see the Installation and Activation page for more details.

• The camera system is fully calibrated. Please see the Calibration page for more details.

• Markers have been applied to all Rigid Body and Trained Markerset assets required in the shoot. For more information about working with these assets, please see the Rigid Body Tracking page, the Trained Markersets page, and the IMU Sensor Fusion page.

• All actors are suited up with markers for the appropriate skeleton markerset. For more information about tracking human movement, please see the Skeleton Tracking page, the Builder Pane page for information about creating and modifying skeletons, and the Skeleton Marker Sets collection of pages for diagrams and details for each of the available skeleton markersets.

Once these items are completed, you are ready to capture Takes.

For real-time tracking applications, please see the Data Streaming page.

Live Mode and Edit Mode

Live Mode

Live mode is used when recording new Takes or when streaming a live capture. In this mode, all enabled cameras continuously capture 2D images and reconstruct the detected reflections into 3D data in real-time.

Edit Mode

Edit Mode is used for playback of captured Take files. In this mode, you can playback or stream recorded data and complete post-processing tasks.

Control Deck

Live Mode

When in Live mode, the Control Deck provides controls to:

• Change the Take name from the default.

• Start or stop recording.

• Delay recording.

• Record for a preset duration of time, or until manually stopped.

Edit Mode

Edit Mode is used for playback of captured Take files. In this mode, you can playback and stream recorded data and complete post-processing tasks. The Cameras View displays the recorded 2D data while the 3D Viewport represents either recorded or real-time processed data as described below.

There are two modes for editing:

• Edit: Playback in standard Edit mode displays and streams the processed 3D data saved in the recorded Take. Changes made to settings and assets are not reflected in the Viewport until the Take is reprocessed.

• Edit 2D: Playback in Edit 2D mode performs a live reconstruction of the 3D data, immediately reflecting changes made to settings or assets. These changes are not applied to the recording until the Take is reprocessed. To playback in 2D mode, click the Edit button and select Edit 2D.

Please see the Data Editing page for more information about editing Takes.

Recording

Recording Delay

The Recording Delay feature adds a countdown before the start of the capture, allowing time to set the scene and ensure all actors are in place.

Recorded Data Management

In Motive, Take file are stored in folders known as session folders.

The Data pane is the primary interface for managing capture files. It displays a list of session folders and the corresponding Take files that are recorded or loaded in Motive.

Tips for Managing Takes

• Plan ahead for the capture day by creating a list of captures in a text file or a spreadsheet. Copy and paste (Ctrl + V) the list into the Data Management pane to create empty Takes as placeholders for the shoot. (e.g. walk, jog, run, jump).

• Start the capture day with a training Take for each Trained Markerset. Once the Markerset assets are created, they can be imported into Live and included in the remaining captures.

• Select one of the empty Takes and start recording. Motive will save the capture using the same name as the selected Take.

• If the capture was unsuccessful, simply record it again. Motive will record additional Takes with an incremented suffix added to the given Take name (e.g. walk_001, walk_002, walk_003). The suffix format is defined on the General tab of the Application Settings panel.

• When the capture is successful, select another empty Take in the list to begin the next capture.

• To close an individual session folder, right-click on the folder and select Remove.

• To close all the open session folders at once, right-click in the empty space in the session folder list and select Remove all Folders.

Recorded Data Types

When a capture is recorded, both 2D data and real-time reconstructed 3D data are saved in the Take. For more details on each data type, refer to the Data Types page.

• 2D data: Consists of the 2D object images captured by each camera.

• 3D data: Reconstructed 3D marker data, solved from the 2D data.

Marker Types in Motive

In the 3D perspective view, marker data displays the 3D positions of the actual markers, as calculated from the camera data. This is distinct from the position of marker constraints in the solver calculation for any assets that include the selected markers.

Markers can be Passive or Active, Labeled or Unlabeled.

Markers associated with Rigid Bodies, Skeletons, or Trained Markersets will use the color properties of the asset rather than the application defaults.

For more detail on markers, please see the Markers page.

Passive and Active Markers

Passive Markers have a retroreflective covering that reflects incoming light back to its source. IR light emitted from the camera is reflected by passive markers, detected by the camera’s sensor, and captured as 2D marker data.

Passive markers that are not part of an asset are white by default.

Active Markers emit a unique LED pulse in sync with a BaseStation for optimal tracking. Active markers are reconstructed and tracked in Motive automatically. The unique illumination pattern ensures each active marker is individually labeled, with an Active ID assigned to the corresponding reconstruction. This applies whether or not the Active Marker is part of an asset.

Active markers that are not part of an asset are cyan by default.

Labeled and Unlabeled Markers

Marker labels are software tags assigned to identify trajectories of reconstructed 3D markers so they can be referenced for tracking individual markers, Rigid Bodies, Skeletons, or Trained Markersets. When an asset is created, the markers used to define it are automatically labeled as part of the asset definition.

Select Simplify Labels (or use hotkey Ctrl + L) to display the marker label without the asset name prefix.

Unlabeled Markers

Markers that are not part of an asset remain unlabeled and are displayed in the 3D Viewport using the selected color values in Applications Settings.

Unlabeled Markers can also result from tracking errors that occur during the capture, such as marker occlusions. You can do another Take, or address labeling errors in post-processing. Please see the Data Editing and Labeling pages for more detail on this process.

Marker Constraints

The reconstructed 3D markers that comprise an asset are known as Constraints in Motive. They appear as transparent spheres that reflect the expected position of a 3D marker in the solved data, based on the asset definition.

For more information about working with Constraints, please see the Constraints Pane page.

BVH File Format

Motive can export tracking data in BioVision Hierarchy (BVH) file format. Exported BVH files do not include individual marker data. Instead, a selected skeleton is exported using hierarchical segment relationships. In a BVH file, the 3D location of a primary skeleton segment (Hips) is exported, and data on subsequent segments are recorded by using joint angles and segment parameters. Only one skeleton is exported for each BVH file, and it contains the fundamental skeleton definition that is required for characterizing the skeleton in other pipelines.

General Export Options

BVH Specific Export Options

C3D Export

Tracking data can be exported into the C3D file format. C3D (Coordinate 3D) is a binary file format that is widely used especially in biomechanics and motion study applications. Recorded data from external devices, such as force plates and NI-DAQ devices, will be recorded within exported C3D files. Note that common biomechanics applications use a Z-up right-hand coordinate system, whereas Motive uses a Y-up right-hand coordinate system. More details on coordinate systems are described in the later section. Find more about C3D files from https://www.c3d.org.

General Export Options

C3D Specific Export Options

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).

MotionBuilder Compatible Axis Convention

This is a preset convention for exporting C3D files for use in Autodesk MotionBuilder. Even though Motive and MotionBuilder both use the same coordinate system, MotionBuilder assumes biomechanics standards when importing C3D files (negative X axis to positive X axis; positive Z to positive Y; positive Z to positive Y). Accordingly, when exporting C3D files for MotionBuilder use, set the Axis setting to MotionBuilder Compatible, and the axes will be exported using the following convention:

• Motive: X axis → Set to negative X → Mobu: X axis

• Motive: Y axis → Set to positive Z → Mobu: Y axis

• Motive: Z axis → Set to positive Y → Mobu: Z axis

Notes on Timecode Export

There is an known behavior where importing C3D data with timecode doesn't accurately show up in MotionBuilder. This happens because MotionBuilder sets the subframe counts in the timecode using the playback rate inside MotionBuilder instead of using the rate of the timecode. When this happens you can set the playback rate in MotionBuilder to be the same as the rate of the timecode generator (e.g. 30 Hz) to get correct timecode. This happens only with C3D import in MotionBuilder, FBX import will work fine without the change to the playback rate.

This page explains different types of captured data in Motive. Understanding these types is essential in order to fully utilize the data-processing pipelines in Motive.

Overview

There are three different types of data: 2D data, 3D data, and Solved data. Each type of data will be covered in detail throughout this page, but basically, 2D Data is the captured camera frame data, 3D Data is the reconstructed 3-dimensional marker data, and Solved data is the calculated positions and orientations of Rigid Bodies and Skeleton segments.