This page includes all of the Motive tutorial video for visual learners.

Motive: Installation and Activation

Motive: Panes and Layouts

Motive: Calibration

Motive: 2D and 3D Views

Motive: Creating Skeleton Assets

Motive: Toolbars and Dropdowns

Motive: Labeling

Motive: File Management

Motive: Timeline Pane

Motive: Labeling using Markersets

Motive: Marker Rays

Overview

Specs

This wiki contains instructions on operating OptiTrack motion capture systems. If you are new to the system, start with the Quick Start Guides to begin your capture experience.

You can navigate through pages using links in the sidebar or using links included within the pages. You can also use the search bar provided on the top-right corner to search for page names and keywords that you are looking for. If you have any questions that are not documented in this wiki or from other provided documentation, please check our forum or contact our Support for further assistance.

• OptiTrack website: http://www.optitrack.com

• The Helpdesk: http://help.naturalpoint.com

• NaturalPoint Forums: https://forums.naturalpoint.com

Site Map

1-2 Color Camera Setup Hardware Requirements

3+ Color Camera Setup Hardware Requirements

Quick Start Hardware Setup

Cabling

Power

Each Prime Color camera must be uplinked and powered through a standard PoE connection that can provide at least 15.4 watts to each port simultaneously.

Windows Setup

Debloat Windows

You'll want to remove as much bloatware from your PC in order to optimize your system and make sure minimal unnecessary background processes are running. Background process can take up valuable CPU resources from Motive and cause frame drops while running your camera system.

There are many external resources in order to remove unused apps and halt unnecessary background processes, so they will not be covered within the scope of this page.

Windows Settings

Firewall and Antivirus Settings

As a general rule for all OptiTrack camera systems, you'll want to disable all Windows firewalls and either disable or remove any Antivirus software. If firewalls and Antivirus software is enabled, this will cause frame drops while running your camera system.

Priority

In order for Motive to run above other processes, you'll need to change the Priority of Motive.exe to High.

• Right Click on the Motive shortcut from your Desktop

• In the Target: text field enter the below path, this will allow Motive to run at High Priority that will persist from closing and reopening Motive.

C:\Windows\System32\cmd.exe /C start "" /high "C:\Program Files\OptiTrack\Motive\Motive.exe"

Processor Affinity (Optional)

If you're running a system with a CPU with a lower core count, you may need to disable Motive from running on a couple of cores. This will help stabilize the overall system and free up some cores for other Windows required processes.

• From the Task Manager, navigate to the Details tab and right click on Motive.exe

• Select Set Affinity

• From this window, uncheck the cores you wish to disallow Motive.exe to run on.

• Click OK

Windows IoT Version

Windows IoT is a stripped down version of Windows OS. This can offer many benefits in terms of running a smooth system with very little 'extras' that come standard with more commercial versions of Windows. Windows IoT can aid further in terms of Prime Color Camera system performance.

Network Setup in Windows

Switch Settings

NIC Settings

NIC

Your Network Interface Card has a few settings that you'll need to change in order to optimize your system and reduce issues when capturing Prime Color Camera video.

To navigate to the camera network's NIC:

• Open Windows Settings

• Select Ethernet from the navigation sidebar

• Under Related settings select Change adapter options

• From the Network Connections pop up window, right click on your NIC and select Properites

• Select the Configure... button and navigate to the Advanced tab

Speed & Duplex

For the Speed and Duplex property, you'll want to change this to the highest throughput of your NIC. If you have a 10Gbps NIC, you'll want to make sure that 10Gbps Full Duplex is selected. This property allows the NIC to operate at it's full range. If this setting is not altered to Full, Windows has the tendency to throttle the NIC throughput causing a 10Gbps NIC to only be sending data at 2Gbps.

Interrupt Moderation

Interrupt Moderation allows the NIC to moderate interrupts. When there is a significant amount of data being uplinked to Motive, this can cause more interrupts to occur thus hindering the system performance. You'll want to Disable this property.

NIC Adapters (Laptop)

Although not recommended, you may use a laptop PC to run Prime Color Camera system. When using a laptop PC, you'll need to use an external network adapter for. The above settings will typically not apply to these types of adapters, so no properties will need to changed.

Motive Setup

Prime Color Settings

Bit Rate

By default this value is set to 50, however, depending on the specifications of your particular system this value may need to be lower or can be raised higher so long as your system can handle the increased data output.

Resolution

By default this value is set to full resolution of 1920 x 1080p. Typically you will not need to alter this setting.

Closing Camera's View

Overview

Specs

Overview

This page is an introduction showing how to use OptiTrack cameras to set up an LED Wall for Virtual Production. This process is also called In-Camera Virtual Effects or InCam VFX. This is an industry technique used to simulate the background of a film set to make it seem as if the actor is in another location.

Hardware

This is a list of required hardware and what each portion is used for.

OptiTrack System

The OptiTrack system is used to track the camera, calibration checkerboard, (optional) LED Wall, and (optional) any other props or additional cameras. As far as OptiTrack hardware is concerned, you will need all of the typical hardware for a motion capture system plus an eSync2, BaseStation, CinePuck, Probe, and a few extra markers. Please refer to the Quick Start Guide for instructions on how to do this.

Computers

Motive and Unreal Engine Computers

You will need one computer to drive Motive/OptiTrack and another to drive the Unreal Engine System.

• Motive PC - The CPU is the most important component and should use the latest generation of processors.

• Unreal Engine PC - Both the CPU and GPU is important. However, the GPU in particular needs to be top of the line to render the scene, for example a RTX 3080 Ti. Setups that involve multiple LED walls stitched together will require graphics cards that can synchronize with each other such as the NVIDIA A6000.

SDI Card

The Unreal Engine computer will also require an SDI input card with both SDI and genlock support. We used the BlackMagic Decklink SDI 4K and the BlackMagic Decklink 8K Pro in our testing, but other cards will work as well.

Studio Camera and Accessories

Studio Camera

You will need a studio video camera with SDI out, timecode in, and genlock in support. Any studio camera with these BNC ports will work, and there are a lot of different options for different budgets. Here are some suggestions:

• Sony PXW-FS7 (What we use internally)

• Canon EOS Series

• Etc...

Cameras without these synchronization features can be used, but may look like they are stuttering due to frames not perfectly aligning.

Camera Movement Device

A camera dolly or other type of mounting system will be needed to move and adjust the camera around your space, so that the movement looks smooth.

Camera Cage

Your studio camera should have a cage around it in order to mount objects to the outside of it. You will need to rigidly mount your CinePuck to the outside. We used SmallRig NATO Rail and Clamps for the cage and Rigid Body mounting fixtures.

Cables

You’ll also need a variety of cables to connect from camera back to where the Computers are located. This includes things such as power cables, BNC cables, USB extension cables (optional for powering the CinePuck), etc... These will not all be listed here, since they will depend on the particular setup for your system.

Lens Encoder (Optional)

Many systems will want a lens encoder in the mix. This is only necessary if you plan on zooming your lens in/out between shoots. We do not use this device in this example for simplicity.

LED Wall

In order to run your LED wall, you will need two things an LED Wall and a Video Processor.

For large walls composed of LED wall subsections you will need an additional video processor and an additional render PC for each wall as well as an SDI splitter. We are using a single LED wall for simplicity.

LED Wall

The LED Wall portion contains the grid of LED light, the power structure, and ways to connect the panels into a video controller, but does not contain the ability to send an HDMI signal to the wall.

We used Planar TVF 125 for our video wall, but there are many other options out there depending on your needs.

Video Processor

The video processor is responsible for taking an HDMI/Display Port/SDI signal and rendering it on the LED wall. It's also responsible for synchronizing the refresh rate of the LED wall with external sources.

The video processor we used for controlling the LED wall was the Color Light Z6. However, Brompton Technology video processors are a more typical film standard.

Timecode and Genlock Generators

You will either need a timecode generator AND a genlock generator or a device that does both. Without these devices the exposure of your camera will not align with when the LED wall renders and you may see the LED wall rendering. These signals are used to synchronize Motive, the cinema camera, LED Walls, and any other devices together.

Setup Instructions

• Timecode - The timecode signal should be fed into Motive and the Cinema camera. The SDI signal from the camera will plug into the SDI card, which will carry the timecode to the Unreal Engine computer as well.

• Genlock - The genlock should be fed into Motive, the cinema camera, and the Video Processor(s).

Timecode

Timecode is for frame alignment. It allows you to synchronize data in post by aligning the timecode values together. (However, it does not guarantee that the cameras expose and the LED wall renders at the same time). There are a variety of different manufactures that will work for timecode generators. Here are some suggestions:

• Evertz HD9010TM

• Tentacle Sync

• UltraSync One

• Etc...

Genlock

Genlock is for frame synchronization. It allows you to synchronize data in real-time by aligning the times when a camera exposes or an LED Wall renders its image. (However, it does not align frame numbers, so one system could be on frame 1 and another on frame 23.) There are a variety of different manufactures that will work for genlock generators. Here are some suggestions:

• Evertz HD9010TM

• BlackMagic Sync Generator

• AJA Gen10

• Etc...

Genlock and Timecode Hardware Connections

Below is a diagram that shows what devices are connected to each other. Both Genlock and Timecode are connected via BNC ports on each device.

• Plug the Genlock Generator into:

  • eSync2's Genlock-In BNC port

  • Any of the Video Processor's BNC ports

  • Studio Video Camera's Genlock port

• Plug the TimeCode Generator into:

  • eSync2's Timecode-In BNC port

  • Studio Video Camera's TC IN BNC port

• Plug the Studio Video Camera into:

  • Unreal Engine PC SDI IN port for Genlock via the SDI OUT port on the Studio Video Camera

  • Unreal Engine PC SDI IN port for Timecode via the SDI OUT port on the Studio Video Camera

Checkerboard

Checkerboard

A rigid board with a black and white checkerboard on it is needed to calibrate the lens characteristics. This object will likely be replaced in the future.

Hardware Checklist

There are a lot of hardware devices required, so below is a rough list of required hardware as a checklist.

OptiTrack

• Truss or other mounting structure

• Prime/PrimeX Cameras

• Ethernet Cables

• Network Switches

• Calibration Wand

• Calibration Square

• Motive License

• License Dongle

• Computer (for Motive)

• Network Card for the Computer

• CinePuck

• BaseStation (for CinePuck)

• eSync2

• BNC Cables (for eSync2)

• Timecode Generator

• Genlock Generator

• Probe (optional)

• Extra markers or trackable objects (optional)

Cinema Camera

• Cinema/Broadcast Camera

• Camera Lens

• Camera Movement Device (ex. dolly, camera rails, etc...)

• Camera Cage

• Camera power cables

• BNC Cables (for timecode, SDI, and Genlock)

• USB C extension cable for powering the CinePuck (optional)

• Lens Encoder (optional)

LED Wall

• Truss or mounting system for the LED Wall

• LED Wall

• Video Processor

• Cables to connect between the LED Wall and Video Processor

• HDMI or other video cables to connect to Unreal PC

• Computer (for Unreal Engine)

• SDI Card for Cinema Camera input

• Video splitters (optional)

• Video recorder (for recording the camera's image)

Other

• Checkerboard for Unreal calibration process

• Non-LED Wall based lighting (optional)

Motive

Next, we'll cover how to configure Motive for tracking.

We assume that you have already set up and calibrated Motive before starting this video. If you need help getting started with Motive, then please refer to our Getting Started wiki page.

IMU Hardware

After calibrating Motive, you'll want to set up your active hardware. This requires a BaseStation and a CinePuck.

BaseStation

• Plug the BaseStation into a Power over Ethernet (PoE) switch just like any other camera.

CinePuck

• Firmly attach the CinePuck to your Studio Camera using your SmallRig NATO Rail and Clamps on the cage of the camera.

• The CinePuck can be mounted anywhere on the camera, but for best results put the puck closer to the lens.

• Turn on your CinePuck, and let it calibrate the IMU bias by waiting until the flashing red and orange lights turn into flashing green lights.

• It is recommended to power the CinePuck using a USB connection for the duration of filming a scene to avoid running out of battery power; a light should turn on the CinePuck when the power is connected.

Motive Settings

• Change the tracking mode to Active + Passive.

• Create a Rigid Body out of the CinePuck markers.

• For active markers, turning up the residual will usually improve tracking.

• Go through a refinement process in the Builder pane to get the highest quality Rigid Body.

• Show advanced settings for that Rigid Body, then input the Active Tag ID and Active RF (radio frequency) Channel for your CinePuck.

• If you don’t have this information, then consult the IMU tag instructions found here Active Marker Tracking: IMU Setup .

You will need to move the Rigid Body around in each axis until it turns back to the original color. At this point you are tracking with both the optical marker data and the IMU data through a process called sensor fusion. This takes the best aspects of both the optical motion capture data and the IMU data to make a tracking solution better than when using either individually. As an option, you may now turn the minimum markers for your Rigid Body down to 1 or even 0 for difficult tracking situations.

IMU Rigid Body Status

LED Wall and Calibration Board

After Motive is configured, we'll need to setup the LED Wall and Calibration Board as trackable objects. This is not strictly necessary for the LED Wall, but will make setup easier later and make setting the ground plane correctly unimportant.

Before configuring the LED Wall and Calibration Board, you'll first want to create a probe Rigid Body. The probe can be used to measure locations in the volume using the calibrated position of the metal tip. For more information for using the probe measurement tool, please feel free to visit our wiki page Measurement Probe Kit Guide.\

LED Wall

• Place four to six markers on the LED Wall without covering the LEDs on the Wall.

• Use the probe to sample the corners of the LED Wall.

• You will need to make a simple plane geometry that is the size of your LED wall using your favorite 3D editing tool such as Blender or Maya. (A sample plane comes with the Unreal Engine Live Link plugin if you need a starting place.)

• If the plane does not perfectly align with the probe points, then you will need to use the gizmo tool to align the geometry. If you need help setting up or using the Gizmo tool please visit our other wiki page Gizmo Tool: Translate, Rotate, and Scale Gizmo.

• Any changes you make to the geometry will need to be on the Rigid Body position and not the geometry offset.

• You can make these adjustments using the Builder pane, then zeroing the Attach Geometry offsets in the Properties pane.

Calibration Board

• Place four to six markers without covering the checkered pattern.

• Use probe to sample the bottom left vertex of the grid.

• Use the gizmo tool to orient the Rigid Body pivot and place pivot in the sampled location.

Genlock and Timecode

Next, you'll need to make sure that your eSync is configured correctly.

Setup Instructions

• If not already done, plug your genlock and timecode signals into the appropriately labeled eSync input ports.

• Select the eSync in the Devices pane.

• In the Properties pane, check to see that your timecode and genlock signals are coming in correctly at the bottom.

• Then, set the Source to Video Genlock In, and set the Input Multiplier to a value of 4 if your genlock is at 30 Hz or 5 if your genlock is at a rate of roughly 24 Hz.

• Your cameras should stop tracking for a few seconds, then the rate in the Devices pane should update if you are configured correctly.

Make sure to turn on Streaming in Motive, then you are all done with the Motive setup.

Unreal Engine

Start Unreal Engine and choose the default project under the “Film, Television, and Live Events” section called “InCamera VFX”

Plugins

Before we get started verify that the following plugins are enabled:

• Camera Calibration (Epic Games, Inc.)

• OpenCV Lens Distortion (Epic Games, Inc.)

• OptiTrack - LiveLink (OptiTrack)

• Media Player Plugin for your capture card (For example, Blackmagic Media Player)

• Media Foundation Media Player

• WMF Media Player

Many of these will be already enabled.

Main Setup

The main setup process consists of four general steps:

• 1. Setup the video media data.

• 2. Setup FIZ and Live Link Sources

• 3. Track and calibrate the camera in Unreal Engine

• 4. Setup nDisplay

1. Setup the Video Media Data

Video Data Source

• Right click in the Content Browser Panel > Media > Media Bundle and name the Media Bundle something appropriate.

• Double click the Media Bundle you just created to open the properties for that object.

• Set the Media Source to the Blackmagic Media Source, the Configuration to the resolution and frame rate of the camera, and set the Timecode Format to LTC (Linear Timecode).

• Drag this Media Bundle object into the scene and you’ll see your video appear on a plane.

Video Data Other Sources

• You’ll also need to create two other video sources doing roughly the same steps as above.

• Right click in the Content Browser Panel > Media > Blackmagic Media Source.

• Open it, then set the configuration and timecode options.

• Right click in the Content Browser Panel > Media > Media Profile.

• Click Configure Now, then Configure.

• Under Media Sources set one of the sources to Blackmagic Media Source, then set the correct configuration and timecode properties.

Timecode and Genlock

Before we set up timecode and genlock, it’s best to have a few visual metrics visible to validate that things are working.

• In the Viewport click the triangle dropdown > Show FPS and also click the triangle dropdown > Stat > Engine > Timecode.

• This will show timecode and genlock metrics in the 3D view.

• If not already open you’ll probably want the Window > Developer Tools > Timecode Provider and Window > Developer Tools > Genlock panels open for debugging.

• You should notice that your timecode and genlock is noticeably incorrect which will be corrected in later steps below.

• The timecode will probably just be the current time.

Timecode Blueprint

• To create a timecode blueprint, right click in the Content Browser Panel > Blueprint > BlackmagicTimecodeProvider and name the blueprint something like “BM_Timecode”.

• The settings for this should match what you did for the Video Data Source.

• Set the Project Settings > Engine General Settings > Timecode > Timecode Provider = “BM_Timecode”.

• At this point your timecode metrics should look correct.

Genlock Blueprint

• Right click in the Content Browser Panel > Blueprint > BlackmagicCustomTimeStep and name the blueprint something like “BM_Genlock”.

• The settings for this should match what you did for the Video Data Source.

• Set the Project Settings > Engine General Settings > Framerate > Custom TimeStep = “BM_Genlock”.

• Your genlock pane should be reporting correctly, and the FPS should be roughly your genlock rate.

2. Setup FIZ and Live Link Sources

FIZ Data

We need to make a blueprint responsible for controlling our lens data.

• Right click the Content Browser > Live Link > Blueprint Virtual Subject, then select the LiveLinkCameraRole in the dropdown.

• Name this file something like “FIZ_Data”.

• Open the blueprint. Create two new objects called Update Virtual Subject Static Data and Update Virtual Subject Frame Data.

• Connect the Static Data one to Event on Initialize and the Frame Data one to Event on Update.

• Right click on the blue Static Data and Frame Data pins and Split Struct Pin.

In the Update Virtual Subject Static Data object:

• Disable Location Supported and Rotation Support, then Enable the Focus Distance Supported, Aperture Supported, and Focal Length Supported options.

• Create three new float variables called Zoom, Iris, and Focus.

• Drag them into the Event Graph and select Get to allow those variables to be accessed in the blueprint.

• Connect Zoom to Frame Data Focal Length, connect Iris to Frame Data Aperture, and connect Focus to Frame Data Focus Distance.

• Compile your blueprint.

• Select your variables and set the default value to the lens characteristics you will be using.

• For our setup we had used:

  • Zoom is 20 mm, Iris is f/2.8 , and the Focus is 260 cm.

• Compile and save your FIZ blueprint.

Lens Data

Both Focus and Iris graphs should create an elongated "S" shape based on the two data points provided for each above.

• To create a lens file right click the Content Browser > Miscellaneous > Lens File, then name the file appropriately.

• Double click the lens file to open it.

• Switch to the Lens File Panel.

• Click the Focus parameter.

• Right click in the graph area and choose Add Data Point, click Input Focus and enter 10, then enter 10 for the Encoder mapping.

• Repeat the above step to create a second data point, but with values of 1000 and 1000.

• Click the Iris parameter.

• Right click in the graph area and choose Add Data Point.

• Click Input Iris and enter 1.4, then enter 1.4 for the Encoder mapping.

• Repeat the above step to create a second data point, but with values of 22 and 22.

• Save your lens file.

Live Link

• In the Window > Live Link pane, click the + Source icon, then Add Virtual Subject.

• Choose the FIZ_Data object that we created above in the FIZ Data section of this OptiTrack Wiki page and add it.

• Click the + Source icon, navigate to the OptiTrack source, and click Create.

• Click Presets and create a new preset.

• Edit > Project Settings and Search for Live Link and set the preset that you just created as the Default Live Link Preset.

You may want to restart your project at this point to verify that the live link pane auto-populates on startup correctly. Sometimes you need to set this preset twice to get it to work.

3. Track and Calibrate the Camera in Unreal Engine

Camera Setup

• From the Place Actors window create an Empty Actor this will act as a camera parent.

• Add it to the nDisplay_InCamVFX_Config object.

• Create another actor object and make it a child of the camera parent actor.

• Zero out the location of the camera parent actor from the Details pane under Transform.

For out setup, in the image to the right, we have labeled the empty actor “Cine_Parent” and its child object “CineCameraActor1” .

• Select the default “CineCameraActor1” object in the World Outliner pane.

• In the Details pane there should be a total of two LiveLinkComponentControllers.

• You can add a new one by using the + Add Component button.

For our setup we have labeled one live link controller “Lens” and the other “OptiTrack”.

OptiTrack Live Link Controller

• Click Subject Representation and choose the Rigid Body associated with your camera.

Lens Live Link Controller

• Click Subject Representation and choose the virtual camera. Then go to “Lens” Live Link Controller then navigate to Role Controllers > Camera Role > Camera Calibration > Lens File Picker and select the lens file you created. This process allows your camera to be tracked and associates the lens data with the camera you will be using.

Tracker Board Setup

• Select the Place Actors window to create an Empty Actor and add it to the nDisplay_InCamVFX_Config object.

• Zero out the location of this actor.

In our setup we have named out Empty Actor "Checkerboard_Parent"

• From the Place Actors window also create a “Camera Calibration Checkerboard” actor for validating our camera lens information later.

• Make it a child of the “Checkerboard” actor from before.

• Configure the Num Corner Row and Num Corner Cols.

• These values should be one less than the number of black/white squares on your calibration board. For example, if your calibration board has 9 rows of alternating black and white squares and 13 columns across of black and white squares, you would input 8 in the Num Corner Row field and 12 in the Num Corner Cols field.

• Also input the Square Side Length which is the measurement of a single square (black or white).

• Set the Odd Cube Materials and Even Cube Materials to solid colors to make it more visible.

• Select "Checkerboard_Parent" and + Add Component of a Live Link Controller.

• Add the checkerboard Rigid Body from Motive as the Subject Representation.

• At this point your checkerboard should be tracking in Unreal Engine.

Lens Information

• Double click the "Lens" file from earlier and go to the Calibration Steps tab and the Lens Information section.

• On the right, select your Media Source.

• Set the Lens Model Name and Serial Number to some relevant values based on what physical lens you are using for your camera.

• The Sensor Dimensions is the trickiest portion to get correct here.

• This is the physical size of the image sensor on your camera in millimeters.

• You will need to consult the documentation for your particular camera to find this information.

• For example, the Sony FS7 is 1920x1080 which we'd input X = 22.78 mm and Y = 12.817 mm for the Sensor Dimensions.

Lens Distortion

The lens information will calculate the intrinsic values of the lens you are using.

• Choose the Lens Distortion Checkerboard algorithm and choose the checkerboard object you created above.

• The Transparency slider can be adjusted between showing the camera image, 3D scene, or a mix of both. Show at least some of the raw camera image for this step.

• Place the checkerboard in the view of the camera, then click in the 2D view to take a sample of the calibration board.

• You will want to give the algorithm a variety of samples mostly around the edge of the image.

• You will also want to get some samples of the calibration board at two different distances. One closer to the camera and one closer to where you will be capturing video.

• Taking samples can be a bit of an art form.

• You will want somewhere around 15 samples.

• Once you are done click Add to Lens Distortion Calibration.

With an OptiTrack system you are looking for a RMS Reprojection Error of around 0.1 at the end. Slightly higher values can be acceptable as well, but will be less accurate.

Nodal Offset

The Nodal Offset tab will calculate the extrinsics or the position of the camera relative to the OptiTrack Rigid Body.

• Select the Nodal Offset Checkerboard algorithm and your checkerboard from above.

• Take samples similar to the Lens Distortion section.

• You will want somewhere around 5 samples.

• Click Apply to Camera Parent.

• This will modify the position of the “Cine_Parent" actor created above.

Last Steps

• Set the Transparency to 0.5.

This will allow you to see both the direct feed from the camera and the 3D overlay at the same time. As long as your calibration board is correctly set up in the 3D scene, then you can verify that the 3D object perfectly overlays on the 2D studio camera image.

4. Setup nDisplay

In the World Outliner, Right click the Edit nDisplay_InCameraVFX_Config button. This will load the controls for configuring nDisplay.

For larger setups, you will configure a display per section of the LED wall. For smaller setups, you can delete additional sections (VP_1, VP_2, and VP_3) accordingly from the 3D view and the Cluster pane.

For a single display:

• Select VP_0 and in the Details pane set the Region > W and H properties to the resolution of your LED display.

• Do the same for Node_0 (Master).

• Select VP_0 and load the plane mesh we created to display the LED wall in Motive.

• Select the "ICVFXCamera" actor, then choose your camera object under In-Camera VFX > Cine Camera Actor.

• Compile and save this blueprint.

• Click Export to save out the nDisplay configuration file. (This file is what you will be asked for in the future in an application called Switchboard, so save it somewhere easy to find.)

Live Link nDisplay Setup

• Go back to your main Unreal Engine window and click on the nDisplay object.

• Click + Add Component and add a Live Link Controller.

• Set the Subject Representation to the Rigid Body for your LED Wall in Motive and set the Component to Control to “SM_Screen_0”.

• At this point your LED Wall should be tracked in the scene, but none of the rendering will look correct yet.

• To validate that this was all setup correctly you can turn off Evaluate Live Link for your CineCamera and move it so that it is in front of the nDisplay LED Wall.

• Make sure to re-enable Evaluate Live Link afterwards.

Reference Object

The next step would be to add whatever reference scene you want to use for your LED Wall Virtual Production shoot. For example, we just duplicated a few of the color calibrators (see image to the right) included with the sample project, so that we have some objects to visualize in the scene.

Save All

If you haven’t already you will need to go to File > Save All at this point. Ideally, you should save frequently during the whole process to make sure you don’t lose your data.

nDisplay Listener

Click the double arrows above the 3D Viewport >> and choose Switchboard > Launch Switchboard Listener. This launches an application that listens for a signal from Switchboard to start your experience.

Start Switchboard

• Click the double arrows above the 3D Viewport >> and choose Launch Switchboard.

• If this is your first time doing this, then there will be a small installer that runs in the command window.

• A popup window will appear.

• Click the Browse button next to the uProject option and navigate to your project file (.uproject).

• Then click Ok and the Switchboard application will launch.

• In Switchboard click Add Device, choose nDisplay, click Browse and choose the nDisplay configuration file (.ndisplay) that you created previously.

• In Settings, verify that the correct project, directories and nDisplay are being referenced.

• Click the power plug icon to Connect all devices.

• Make sure to save and close your Unreal Engine project.

• Click the up arrow button to Start All Connected Devices.

The image on the LED wall should look different when you point the camera at it, since it is calculating for the distortion and position of the lens. From the view of the camera it should almost look like you are looking through a window where the LED wall is located.

Optimize the Camera's View

You might notice that the edge of the camera’s view is a hard edge. You can fix this and expand the field of view slightly to account for small amounts of lag by going back to your Unreal Engine project into the nDisplay object.

• Select the "ICVFXCamera" object in the Components pane.

• In the Details pane set the Field of View Multiplier to a value of about 1.2 to account for any latency, then set the Soft Edge > Top and Bottom and Sides properties to around .25 to blur the edges.

Final Product

From an outside perspective, the final product will look like a static image that updates based on where the camera is pointing. From the view of the cameras, it will essentially look like you are looking through a window to a different world.

In our example, we are just tracking a few simple objects. In real productions you’ll use high quality 3D assets and place objects in front of the LED wall that fit with the scene behind to create a more immersive experience, like seen in the image to the right. With large LED walls, the walls themselves provide the natural lighting needed to make the scene look realistic. With everything set up correctly, what you can do is only limited by your budget and imagination.

Troubleshooting

With an optimized system setup, motion capture systems are capable of obtaining extremely accurate tracking data from a small to medium sized capture volume. This quick start guide includes general tips and suggestions on precision capture system setups and important cautions to keep in mind. This page also covers some of the precision verification methods in Motive. For more general instructions, please refer to the Quick Start Guide: Getting Started or corresponding workflow pages.

Residual Value

Before going into details on precision tracking with an OptiTrack system, let's start with a brief explanation of the residual value, which is the key reconstruction output for monitoring the system precision. The residual value is an average offset distance, in mm, between the converging rays when reconstructing a marker; hence indicating preciseness of the reconstruction. A smaller residual value means that the tracked rays converge more precisely and achieve more accurate 3D reconstruction. A well-tracked marker will have a sub-millimeter average residual value. In Motive, the tolerable residual distance is defined from the Reconstruction Settings under the Application Settings panel.

When one or more markers are selected in the Live mode or from the 2D Mode of capture data, the corresponding mean residual value is displayed over the Status Panel located at the bottom-right corner of Motive.

Capture Volume

First of all, optimize the capture volume for the most precise and accurate tracking results. Avoid a populated area when setting up the system and recording a capture. Clear any obstacles or trip hazards around the capture volume. Physical impacts on the setup will distort the calibration quality, and it could be critical especially when tracking at a sub-millimeter accuracy. Lastly, for best results, routinely recalibrate the capture volume.

Infrared Black Background Objects

Motion capture cameras detect reflected infrared light. Thus, having other reflective objects in the volume will alter the results negatively, which could be critical especially for precise tracking applications. If possible, have background objects that are IR black and non-reflective. Capturing in a dark background provides clear contrast between bright and dark pixels, which could be less distinguishable in a white background.

Camera Placement

Optimized camera placement techniques will greatly improve the tracking result and the measurement accuracy. The following guide highlights important setup instructions for the small volume tracking. For more details on general system setup, read through the Hardware Setup pages.

Mounting Locations

For precise tracking, better results will be obtained by placing cameras closer to the target object (adjusting focus will be required) in a sphere or dome-shaped camera arrangement, as shown in the images on the right. Good positional data in all dimensions (X, Y, and Z axis) will be attained only if there are cameras contributing to the calculation from a variety of different locations; each unique vantage adds additional data.

Mount Securely

For most accurate results, cameras should be perfectly stationary, securely fastened onto a truss system or an extremely rigid object. Any slight deformation or fluctuation to the mount structures may affect the result in sub-millimeter tracking applications. A small-sized truss system is ideal for the setup. Take extreme caution when mounting onto speed rails attached to a wall, because the building may fluctuate on hot days.

Focus and Aiming

F-stop

Increase the f-stop higher (smaller aperture) to gain a larger depth of field. Increased depth of field will make the greater portion of the capture volume in-focus and will make measurements more consistent throughout the volume.

Aim and Focus

Especially for close-up captures, camera aim and focus should be adjusted precisely. Aim the cameras towards the center of the capture volume. Optimize the camera focus by zooming into a marker in Motive, and rotating the focus knob on the camera until the smallest marker is captured with clearest image contrast. To zoom in and out from the camera view, place the mouse cursor over the 2D camera preview window in Motive and use the mouse-scroll.

For more information, please read through the Aiming and Focusing workflow page.

Motive Settings

The following sections cover key configuration settings which need to be optimized for the precision tracking.

Camera Settings

Camera settings are configured using the Devices pane and the Properties pane both of which can be opened under the view tab in Motive.

Live-Reconstruction Settings

Live-reconstruction settings can be configured under the application settings panel. These settings determine which data gets reconstructed into the 3D data, and when needed, you can adjust the filter thresholds to prevent any inaccurate data from reconstructing. Read through the Application Settings page for more details on each setting. For the precision tracking applications, the key settings and the suggested values are listed below:

Calibration

The following calibration instructions are specific to precision tracking. For more general information, refer to the Calibration page.

Wands

For calibrating small capture volumes for precision tracking, we recommend using a Micron Series wand, either the CWM-250 or CWM-125. These wands are made of invar alloy, very rigid and insensitive to temperature, and they are designed to provide a precise and constant reference dimension during calibration. At the bottom of the wand head, there is a label which shows a factory-calibrated wand length with a sub-millimeter accuracy. In the Calibration pane, select Micron Series under the OptiWand dropdown menu, and define the exact length under the Wand Length.

The CW-500 wand is designed for capturing medium to large volumes, and it is not suited for calibrating small volumes. Not only it does not have the indication on the factory-calibrated length, but it is also made of aluminum, which makes it more vulnerable to thermal expansions. During the wanding process, Motive references the wand length for calibrating the capture volume, and any distortions in the wand length would cause the calibrated capture volume to be scaled slightly differently, which can be significant when capturing precise measurements. For this reason, a micron series wand is suitable for precision tracking applications.

Note: Never touch the marker on the CWM-250 or CWM-125 since any changes can affect the calibration and overall data.

Calibration Results

Calibration reports and analyzing the reported error is a complicated subject because the calibration process uses its own samples for validation. For example, sampling near the edge of the volume may improve the accuracy of the system but provide slightly worse calibration results. This is because the samples near the edge will have more errors to be corrected. Acceptable mean error varies based on the size of your volume, the number of cameras, and desired accuracy. The key metrics to keep an eye on are the Mean 3D Error for the Overall Reprojection and the Wand Error. Generally, use calibrations with the Mean 3D Error less than 0.80 mm and the Wand Error less than 0.030 mm. These numbers may be hard to reproduce in regular volumes. Again, the acceptable numbers are subjective, but lower numbers are better in general.

Tracking

Marker Type

In general, passive retro-reflective markers will provide better tracking accuracy. The boundary of the spherical marker can be more clearly distinguished on passive markers, and the system can identify an accurate position of the marker centroids. The active markers, on the other hand, emit light and the illumination may not appear as spherical on the camera view. Even if a spherical diffuser is used, there can be situations where the light is not evenly distributed. This could provide inaccurate centroid data. For this reason, passive markers are preferred for precision tracking applications.

Marker Placement

For close-up capture, it could be inevitable to place markers close to one another, and when markers are placed in close vicinity, their reflections may be merged as seen by the camera’s imager. Merged reflections will have an inaccurate centroid location, or they may even be completely discarded by the circularity filter or the intrusion detection feature. For best results, keep the circularity filter at a higher setting (>0.6) and decrease the intrusion band in the camera group 2D filter settings to make sure only relevant reflections are reconstructed. The optimal balance will depend on the number and arrangement of the cameras in the setup.

There are editing methods to discard or modify the missing data. However, for most reliable results, such marker intrusions should be prevented before the capture by separating the marker placements or by optimizing the camera placements.

Refine Rigid Body Definition

Once a Rigid Body is defined from a set of reconstructed points, utilize the Rigid Body Refinement feature to further refine the Rigid Body definition for precision tracking. The tool allows Motive to collect additional samples in the live mode for achieving more accurate tracking results.

See: Rigid Body Refinement

Camera Temperature

In a mocap system, camera mount structures and other hardware components may be affected by temperature fluctuations. Refer to linear thermal expansion coefficient tables to examine which materials are susceptible to temperature changes. Avoid using a temperature sensitive material for mounting the cameras. For example, aluminum has relatively high thermal expansion coefficient, and therefore, mounting cameras onto aluminum mounting structures may distort the calibration quality. For best accuracy, routinely recalibrate the capture volume, and take the temperature fluctuation into an account both when selecting the mount structures and before collecting data.

Ambient Temperature

An ideal method of avoiding influence from environmental temperature is to install the system in a temperature controlled volume. If such option is unavailable, routinely calibrate the volume before capture, and recalibrate the volume in between sessions when capturing for a long period. The effects are especially noticeable on hot days and will significantly affect your results. Thus, consistently monitor the average residual value and how well your rays converge to individual markers.

Camera Heat

The cameras will heat up with extended use, and change in internal hardware temperature may also affect the capture data. For this reason, avoid capturing or calibrating right after powering the system. Tests have found that the cameras need to be warmed up in Live mode for about an hour until it reaches a stable temperature. Typical stable temperatures are between 40-50 degrees Celsius or 25 degree Celsius above the ambient temperature. For Ethernet camera models, camera temperatures can be monitored from the Cameras View in Motive (Cameras View > Eye Icon > Camera Info).

Attention: Vibrations

Especially for measuring at sub-millimeters, even a minimal shift of the setup can affect the recordings. Re-calibrate the capture volume if your average residual values start to deviate. In particular, watch out for the following:

• Avoid touching the cameras and the camera mounts.

• Keep the capture area away from heavy foot traffic. People shouldn't be walking around the volume while the capture is taking place.

• Closing doors, even from the outside, may be noticeable during recording.

Reconstruction Verification

The following methods can be used to check the tracking accuracy and to better optimize the reconstructions settings in Motive.

Verification Method 1

Verification Method 2

The calibration quality can also be analyzed by checking the convergence of the tracked rays into a marker. This is not as precise as the first method, but the tracked rays can be used to check the calibration quality of multiple cameras at once. First of all, make sure tracked rays are visible; Perspective View pane > Eye button > Tracked Rays. Then, select a marker in the perspective view pane. Zoom all the way into the marker (you may need to zoom into the sphere), and you will be able to see the tracking rays (green) converging into the center of the marker. A good calibration should have all the rays converging into approximately one point, as shown in the following image. Essentially, this is a visual way of examining the average residual offset of the converging rays.

Continuous Calibration

In Motive 3.0, a new feature was introduced called Continuous Calibration. This can aid in keeping your precision for longer in between calibrations. For more information regarding continuous calibration please refer to our Wiki page Continuous Calibration.

Welcome to the Quick Start Guide: Getting Started!

This guide provides a quick walk-through of installing and using OptiTrack motion capture systems. Key concepts and instructions are summarized in each section of this page to help you get familiarized with the system and get you started with the capture experience.

Note that Motive offers features far beyond the ones listed in this guide, and the capability of the system can be further optimized to fit your specific capture applications using the additional features. For more detailed information on each workflow, read through the corresponding workflow pages in this wiki: hardware setup and software setup.

Hardware Setup

Preparing the Capture Area

For best tracking results, you need to prepare and clean up the capture environment before setting up the system. First, remove unnecessary objects that could block the camera views. Cover open windows and minimize incoming sunlight. Avoid setting up a system over reflective flooring since IR lights from cameras may get reflected and add noise to the data. If this is not an option, use rubber mats to cover the reflective area. Likewise, items with reflective surfaces or illuminating features should be removed or covered with non-reflective materials in order to avoid extraneous reflections.

Key Checkpoints for a Good Capture Area

• Minimize ambient lights, especially sunlight and other infrared light sources.

• Clean capture volume. Remove unnecessary obstacles within the area.

• Tape, or Cover, remaining reflective objects in the area.

See Also: Hardware Setup workflow pages.

Cabling and Load Balancing

Ethernet Camera System

Ethernet Camera Models: PrimeX series and SlimX 13 cameras. Follow the below wiring diagram and connect each of the required system components.

See Also: Network setup page.

Placing and Aiming Cameras

Optical motion capture systems utilize multiple 2D images from each camera to compute, or reconstruct, corresponding 3D coordinates. For best tracking results, cameras must be placed so that each of them captures unique vantage of the target capture area. Place the cameras circumnavigating around the capture volume, as shown in the example below, so that markers in the volume will be visible by at least two cameras at all times. Mount cameras securely onto stable structures (e.g. truss system) so that they don't move throughout the capture. When using tripods or camera stands, ensure that they are placed in stable positions. After placing cameras, aim the cameras so that their views overlap around the region where most of the capture will take place. Any significant camera movement after system calibration may require re-calibration. Cable strain-relief should be used at the camera end of camera cables to prevent potential damage to the camera.

See Also: Camera Placement and Camera Mount Structures pages.

Lens Focus

In order to obtain accurate and stable tracking data, it is very important that all of the cameras are correctly focused to the target volume. This is especially important for close-up and long-range captures. For common tracking applications in general, focus-to-infinity should work fine, however, it is still important to confirm that each camera in the system is focused.

To adjust or to check camera focus, place some markers on the target tracking area. Then, set the camera to raw grayscale mode, increase the exposure and LED settings, and then Zoom onto one of the retroreflective markers in the capture volume and check the clarity of the image. If the image is blurry, adjust the camera focus and find the point where the marker is best resolved.

See Also: Aiming and Focusing page.

Software Setup

Host PC Requirements

In order to properly run a motion capture system using Motive, the host PC must satisfy the minimum system requirements. Required minimum specifications vary depending on sizes of mocap systems and types of cameras used. Consult our Sale Engineers, or use the Build Your Own feature on our website to find out host PC specification requirements.

Motive Installation

Motive is a software platform designed to control motion capture systems for various tracking applications. Motive not only allows the user to calibrate and configure the system, but it also provides interfaces for both capturing and processing of 3D data. The captured data can be recorded or live-streamed into other pipelines.

If you are new to Motive, we recommend you to read through Motive Basics page after going through this guide to learn about basic navigation controls in Motive.

Motive Activation Requirements

The following items will be required for activating Motive. Please note that the valid duration of the Motive license must be later than the release date of the version that you are activating. If the license is expired, please update the license or use an older version of Motive that was released prior to the license expiration date.

• Motive 3.x license

• USB Security Key

Host PC Requirements

Required PC specifications may vary depending on the size of the camera system. Generally, you will be required to use the recommended specs with a system with more than 24 cameras.

Download and Install

To install Motive, simply download the Motive software installer for your operating system from the Motive Download Page, then run the installer and follow its prompts.

License Activation Steps

1. Insert the USB Security Key into a USB-C port on the computer. If needed, you can also use a USB-A adapter to connect.

2. Launch Motive

3. Activate your software using the License Tool, which can be accessed in the Motive splash screen. You will need to input the License Serial Number and the Hash Code for your license.

4. After activation, the License tool will place the license file associated to the USB Security Key in the License folder. For more license activation questions, visit Licensing FAQs or contact our Support.

First Launch

By default, Motive will start on the calibration layout with all the necessary panes open. Using this layout, you can calibrate the camera system and construct a 3D tracking volume. The layout may be slightly different for certain camera models or software licenses.

The following panes will be open:

Viewport Navigation

Use the following controls for navigating throughout the 2D and 3D viewports in Motive. Most of the navigation controls are customizable, including both mouse actions and hotkeys. These mouse and keyboard controls can be customized through the Application Settings panel.

Camera Settings

Now that the cameras are connected and showing up in Motive, the next step is to configure the camera settings. Appropriate camera settings will vary depending on various factors including the capture environment and tracked objects. The overall goal is to configure the settings so that the marker reflections are clearly captured and distinguished in the 2D view of each camera. For a detailed explanation on individual settings, please refer to the Devices pane page.

To check whether the camera setting is optimized, it is best to check both the grayscale mode images and tracking mode (Object or Precision) images and make sure the marker reflection stands out from the image. You switch a camera into grayscale mode either in Motive or by using the Aim Assist button for supported cameras. In Motive, you can right-click on the Cameras Viewport and switch the video mode in the context menu, or you can also change the video mode through the Properties pane.

Exposure Setting

The exposure setting determines how long the camera imagers are exposed per each frame of data. With longer the exposure, more light will be captured by the camera, creating the brighter images that can improve visibility for small and dim markers. However, high exposure values can introduce false markers, larger marker blooms, and marker blurring – all of which can negatively impact marker data quality. It is best to minimize the exposure setting as long as the markers are clearly visible in the captured images.

System Calibration

In order to start tracking, all cameras must first be calibrated. Through the camera calibration process, Motive computes position and orientation of cameras (extrinsic) as well as amounts of lens distortions in captured images (intrinsics). Using the calibration results, Motive constructs a 3D capture volume, and within this volume, motion tracking is accomplished. All of the calibration tools can be found under the Calibration pane. Read through the Calibration page to learn about the calibration process and what other tools are available for more efficient workflows.

See Also: Calibration page.

Calibration Steps

Starting a Calibration

To start a system calibration, open the Calibration Pane. Under the Calibration pane, you can choose to start a new calibration or to modify the existing one. For this guide, click New Calibration for a fresh calibration.

Masking

Before the system calibration, any extraneous reflections or unnecessary markers should ideally be removed or covered so that they are not seen by the cameras. However, it may not always be possible to remove all of them. In this case, these extraneous reflections can be ignored by applying masks over them during the calibration.

1. Check the calibration pane to see if any of the cameras are seeing extraneous reflections or noise in their view. A warning sign will appear over these cameras.

2. Check the camera view of the corresponding camera to identify where the extraneous reflection is coming from, and if possible, remove them from the capture volume or cover them so that the cameras do not see them.

3. If reflections still exist, click Mask to automatically apply masks over all of the reflections detected in the camera views.

4. Once all of the reflections have been masked or removed, click Continue to proceed to the wanding step.

Wanding

In the wanding stage, we will use the Calibration Wand to collect wanding samples that will be used for calibrating the system.

1. Set the Calibration Type to Full.

2. Under the Wand settings, specify the wand that you will be used to calibrate the volume. It is very important to input the matching wand size here. When an incorrect dimension is given to Motive, the calibrated 3D volume will be scaled incorrectly.

3. Click Start Wanding to start collecting the wanding sample.

4. Once the wanding process starts. Bring your calibration wand into the capture volume and start waving the wand gently across the entire capture volume. Gently draw figure-eight repetitively with the wand to collect samples at varying orientations and cover as much space as possible for sufficient sampling. Wanding trails will be shown in colors on the 2D View. A grid/table displaying the status of the wanding process will show up in the Calibration pane to monitor the progress.

5. As each camera collects the wanding samples, the camera grid representing the wanding status of each camera will start changing its color to bright green. This provides visual feedback on whether sufficient samples have been collected by each camera. Wave the wand until all boxes are filled with bright green color.

6. Once enough samples have been collected, press the Start Calculation button to start calibrating. The calculation may take a few minutes to complete.

7. When the calculation is finished, its results will get displayed. If the overall result is acceptable, click Continue to proceed to setting up the ground. If the result is not satisfactory, click Cancel and go through the wanding once more.

Setting the Ground Plane

Now that all of the cameras have been calibrated, the next step is to define the ground plane of the capture volume.

1. Place a Calibration Square inside the capture volume. Position the square so that the vertex marker is placed directly over the desired global origin.

2. Orient the calibration square so that the longer arm is directed towards the desired +Z axes and the shorter arm is directed towards the desired +X axes of the volume. Motive uses the y-up right-hand coordinate system.

3. Level the calibration square parallel to the ground plane.

4. At this point, the Calibration pane should detect which calibration square has been placed in the tracking volume. If not, you may want to specifically select the three markers on the calibration square from the 3D view in Motive.

5. Click Set Ground Plane to complete the calibration.

Capture Setup

Once the camera system has been calibrated, Motive is ready to collect data. But before doing so, let's prepare the session folders for organizing the capture recordings and define the trackable assets, including Rigid Body and/or Skeletons.

Set Up for Capture Session

Motive Recordings

See Also: Motive Basics page.

Motive Profiles

Motive's software configurations are saved to Motive Profiles (*.motive extension). All of the application-related settings can be saved into the Motive profiles, and you can export and import these files and easily maintain the same software configurations.

Marker Up

Place the retro-reflective markers onto subjects (Rigid Body or Skeleton) that you wish to track. Double-check that the markers are attached securely. For skeleton tracking, open the Builder pane, go to skeleton creation options, and choose a marker set you wish to use. Follow the skeleton avatar diagram for placing the markers. If you are using a mocap suit, make sure that the suit fits as tightly as possible. Motive derives the position of each body segment from related markers that you place on the suit. Accordingly, it is important to prevent the shifting of markers as much as possible. Sample marker placements are shown below.

See Also: Markers page for marker types, or Rigid Body Tracking and Skeleton Tracking page for placement directions.

Define Skeletons and Rigid Bodies

Create Rigid Body

To define a Rigid Body, simply select three or more markers in the Perspective View, right-click, and select Rigid Body → Create Rigid Body From Selected. You can also utilize CTRL+T hotkey for creating Rigid Body assets. You can also use the Builder pane to define the Rigid Body.

Create Skeleton

To define a skeleton, have the actor enter the volume with markers attached at appropriate locations. Open the Builder pane and select Skeleton and Create. Under the marker set section, select a marker set you wish to use, and a corresponding model with desired marker locations will be displayed. After verifying that the marker locations on the actor correspond to those in the Builder pane, instruct the actor to strike the calibration pose. Most common calibration pose used is the T-pose. The T-pose requires a proper standing posture with back straight and head looking directly forward. Then, both arms are stretched to sides, forming a “T” shape. While in T-pose, select all of the markers within the desired skeleton in the 3D view and click Create button in the Builder pane. In some cases, you may not need to select the markers if only the desired actor is in view.

See Also: Rigid Body Tracking page and Skeleton Tracking page.

Record Data

Once the volume is calibrated and skeletons are defined, now you are ready to capture. In the Control Deck at the bottom, press the dimmed red record button or simply press the spacebar when in the Live mode to begin capturing. This button will illuminate in bright red to indicate recording is in progress. You can stop recording by clicking the record button again, and a corresponding capture file (TAK extension), also known as capture Take, will be saved within the current session folder. Once a Take has been saved, you can playback captures, reconstruct, edit, and export your data in a variety of formats for additional analysis or use with most 3D software.

When tracking skeletons, it is beneficial to start and end the capture with a T-pose. This allows you to recreate the skeleton in post-processing when needed.

See Also: Data Recording page.

Post-Capture

Data Editing

After capturing a Take. Recorded 3D data and its trajectories can be post-processed using the Data Editing tools, which can be found in the Edit Tools pane. Data editing tools provide post-processing features such as deleting unreliable trajectories, smoothing select trajectories, and interpolating missing (occluded) marker positions. Post-editing the 3D data can improve the quality of tracking data.

General Editing 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

Marker Labeling

Markers detected in the camera views get trajectorized into 3D coordinates. The reconstructed markers need to be labeled for Motive to distinguish different trajecectories within a capture. Trajectories of annotated reconstructions can be exported individually or used (solved altogether) to track the movements of the target subjects. Markers associated with Rigid Bodies and Skeletons are labeled automatically through the auto-labeling process. Note that Rigid Body and Skeleton markers can be auto-labeled both during Live mode (before capture) and Edit mode (after capture). Individual markers can also be labeled, but each marker needs to be manually labeled in post-processing using assets and the Labeling pane. These manual Labeling tools can also be used to correct any labeling errors. Read through the Labeling page for more details in assigning and editing marker labels.

• Auto-label: Automatically label sets of Rigid Body markers and skeleton markers using the corresponding asset definitions.

• Manual Label: Labeling individual markers manually using the Labeling, assigning labels defined in the Marker Set, Rigid Body, or Skeleton assets.

See Also: Labeling page.

Data Export

Motive exports reconstructed 3D tracking data in various file formats, and exported files can be imported into other pipelines to further utilize capture data. Supported formats include CSV and C3D for Motive: Tracker, and additionally, FBX, BVH, and TRC for Motive: Body. To export tracking data, select a Take to export and open the export dialog window, which can be accessed from File → Export Tracking Data or right-click on a Take → Export Tracking data from the Data pane. Multiple Takes can be selected and exported from Motive or by using the Motive Batch Processor. From the export dialog window the frame rate, measurement scale, and frame range of exported data can be configured. Frame ranges can also be specified by selecting a frame range in the Graph View pane before exporting a file. In the export dialog window, corresponding export options are available for each file format.

See Also: Data Export page.

Data Streaming

Motive offers multiple options to stream tracking data onto external applications in real-time. Tracking data can be streamed in both Live mode and Edit mode. Streaming plugins are available for Autodesk Motion Builder, Visual3D, The MotionMonitor, Unreal Engine 4, 3ds Max, Maya (VCS), and VRPN, and they can be downloaded from the OptiTrack website. For other streaming options, the NatNet SDK enables users to build custom client and server applications to stream capture data. Common motion capture applications rely on real-time tracking, and the OptiTrack system is designed to deliver data at an extremely low latency even when streaming to third-party pipelines. Detailed instructions on specific streaming protocols are included in the PDF documentation that ships with the respective plugins or SDK's.

See Also: Data Streaming page

This page provides instructions on how to set up and use the OptiTrack active marker solution.

Overview

The OptiTrack Active Tracking solution allows synchronized tracking of active LED markers using an OptiTrack camera system. Consisting of the Base Station and the users choice Active Tags that can be integrated in to any object and/or the "Active Puck" which can act as its own single Rigid Body.

Connected to the camera system the Base Station emits RF signals to the active markers, allowing precise synchronization between camera exposure and illumination of the LEDs. Each active marker is now uniquely labeled in Motive software, allowing more stable Rigid Body tracking since active markers will never be mislabeled and unique marker placements are no longer be required for distinguishing multiple Rigid Bodies.

Hardware Setup

Required Component

BaseStation

Sends out radio frequency signals for synchronizing the active markers.

• Powered by PoE, connected via Ethernet cable.

• Must be connected to one of the switches in the camera network.

Active Marker Options

Active Tag

• Connects to a USB power source and illuminates the active LEDs.

• Receives RF signals from the Base Station and correspondingly synchronizes illumination of the connected active LED markers.

• Emits 850 nm IR light.

• 4 active LEDs in each bundle and up to two bundles can be connected to each Tag.

• (8 Active LEDs (4(LEDs/set) x 2 set) per Tag)

• Size: 5 mm (T1 ¾) Plastic Package, half angle ±65°, typ. 12 mW/sr at 100mA

Active Pucks

An active tag self-contained into a trackable object, providing information with 6 DoF for any arbitrary object that it's attached to. Carries a factory installed Active Tag with 8 LEDs and a rechargeable battery with up to 10-hours of run time on a single charge.

Wiring the Components

Camera System

• Active tracking is supported only with the Ethernet camera system (Prime series or Slim 13E cameras). For instructions on how to set up a camera system see: Hardware Setup.

BaseStation

• Connects to one of the PoE switches within the camera network.

• For best performance, place the base station near the center of your tracking space, with unobstructed lines of sight to the areas where your Active Tags will be located during use. Although the wireless signal is capable of traveling through many types of obstructions, there still exists the possibility of reduced range as a result of interference, particularly from metal and other dense materials.

• Do not place external electromagnetic or radiofrequency devices near the Base Station.

• When Base Station is working properly, the LED closest to the antenna should blink green when Motive is running.

Tag Setup

• Connect two sets of active markers (4 LEDs in each set) into a Tag.

• Connect the battery and/or a micro USB cable to power the Tag. The Tag takes 3.3V ~ 5.0V of inputs from the micro USB cable. For powering through the battery, use only the batteries that are supplied by us. To recharge the battery, have the battery connected to the Tag and then connect the micro USB cable.

• To initialize the Tag, press on the power switch once. Be careful not to hold down on the power switch for more than a second, because it will trigger to start the device in the firmware update (DFU) mode. If it initializes in the DFU mode, which is indicated by two orange LEDs, just power off and restart the Tag. To power off the Tag, hold down on the power switch until the status LEDs go dark.

• Once powered, you should be able to see the illumination of IR LEDs from the 2D reference camera view.

Puck Setup

• Press the power button for 1~2 seconds and release. The top-left LED will illuminate in orange while it initializes. Once it initializes the bottom LED will light up green if it has made a successful connection with the base station. Then the top-left LED will start blinking in green indicating that the sync packets are being received.

• For more information, please read through the Active Puck page.

Motive Settings

Active Pattern Depth

Settings → Live Pipeline → Solver Tab with Default value = 12

This adjusts the complexity of the illumination patterns produced by active markers. In most applications, the default value can be used for quality tracking results. If a high number of Rigid Bodies are tracked simultaneously, this value can be increased allowing for more combinations of the illumination patterns on each marker. If this value is set too low, duplicate active IDs can be produced, should this error appear increase the value of this setting.

Minimum Active Count

Settings → Live Pipeline → Solver Tab with Default value = 3

Setting the number of rays required to establish the active ID for each on frame of an active marker cycle. If this value is increased, and active makers become occluded it may take longer for active markers to be reestablished in the Motive view. The majority of applications will not need to alter this setting.

Active Marker Color

Settings → Views → 3D Tab with Default color = blue

The color assigned to this setting will be used to indicate and distinguish active and passive markers seen in the viewer pane of Motive.

Camera Settings

For tracking of the active LED markers, the following camera settings may need to be adjusted for best tracking results:

Camera Exposure

For tracking the active markers, set the camera exposures a bit higher compared to when tracking passive markers. This allows the cameras to better detect the active markers. The optimal value will vary depending on the camera system setups, but in general, you would want to set the camera exposure between 400 ~ 750, microseconds.

IR LEDs

When tracking only active markers, the cameras do not need to emit IR lights. In this case, you can disable the IR settings in the Devices pane.

Active Markers in Motive

Active Labels

Labels in Recorded 3D Data

Unlabeled Markers

In recorded 3D data, the labels of the unlabeled active markers will still indicate that it is an active marker. As shown in the image below, there will be Active prefix assigned in addition to the active ID to indicate that it is an active marker. This applies only to individual active markers that are not auto-labeled. Markers that are auto-labeled using a trackable model will be assigned with a respective label.

Auto-labeled Markers

When a trackable asset (e.g. Rigid Body) is defined using active markers, its active ID information gets stored in the asset along with marker positions. When auto-labeling the markers in the space, the trackable asset will additionally search for reconstructions with matching active ID, in addition to the marker arrangements, to auto-label a set of markers. This can add additional guard to the auto-labeler and prevents and mis-labeling errors.

Rigid Body Definition

Rigid Body definitions created from actively labeled reconstructions will search for respective marker IDs in order to solve the Rigid Body. This gives a huge benefit because the active markers can be placed in perfectly symmetrical marker arrangements among multiple Rigid Bodies and not run into labeling swaps. With active markers, only the 3D reconstructions with active IDs stored under the corresponding Rigid Body definition will contribute to the solve.

Rigid Body Properties

If a Rigid Body was created from actively labeled reconstructions, the corresponding Active ID gets saved under the corresponding Rigid Body properties. In order for the Rigid Body to be tracked, the reconstructions with matching marker IDs in addition to matching marker placements must be tracked in the volume. If the active ID is set to 0, it means no particular marker ID is given to the Rigid Body definition and any reconstructions can contribute to the solve.

Troubleshooting

PrimeX 41, PrimeX 22, Prime 41*, and Prime 17W* camera models have powerful tracking capability that allows tracking outdoors. With strong infrared (IR) LED illuminations and some adjustments to its settings, a Prime system can overcome sunlight interference and perform 3D capture. This page provides general hardware and software system setup recommendations for outdoor captures.

Please note that when capturing outdoors, the cameras will have shorter tracking ranges compared to when tracking indoors. Also, the system calibration will be more susceptible to change in outdoor applications because there are environmental variables (e.g. sunlight, wind, etc.) that could alter the system setup. To ensure tracking accuracy, routinely re-calibrate the cameras throughout the capture session.

Weather and Backgrounds

Even though it is possible to capture under the influence of the sun, it is best to pick cloudy days for captures in order to obtain the best tracking results. The reasons include the following:

• Bright illumination from the daylight will introduce extraneous reconstructions, requiring additional effort in the post-processing on cleaning up the captured data.

• Throughout the day, the position of the sun will continuously change as will the reflections and shadows of the nearby objects. For this reason, the camera system needs to be routinely re-masked or re-calibrated.

The surroundings can also work to your advantage or disadvantage depending on the situation. Different outdoor objects reflect 850 nm Infrared (IR) light in different ways that can be unpredictable without testing. Lining your background with objects that are black in Infrared (IR) will help distinguish your markers from the background better which will help with tracking. Some examples of outdoor objects and their relative brightness is as follows:

• Grass typically appears as bright white in IR.

• Asphalt typically appears dark black in IR.

• Concrete depends, but it's usually a gray in IR.

Hardware Setup Recommendations

In general, setting up a truss system for mounting the cameras is recommended for stability, but for outdoor captures, it could be too much effort to do so. For this reason, most outdoor capture applications use tripods for mounting the cameras.

Do not aim the cameras directly towards the sun. If possible, place and aim the cameras so that they are capturing the target volume at a downward angle from above.

Increase the f-stop setting in the Prime cameras to decrease the aperture size of the lenses. The f-stop setting determines the amount of light that is let through the lenses, and increasing the f-stop value will decrease the overall brightness of the captured image allowing the system to better accommodate for sunlight interference. Furthermore, changing this allows camera exposures to be set to a higher value, which will be discussed in the later section. Note that f-stop can be adjusted only in PrimeX 41, PrimeX 22, Prime 41*, and Prime 17W* camera models.

4. [Camera Setup] Utilize shadows

Even though it is possible to capture under sunlight, the best tracking result is achieved when the capture environment is best optimized for tracking. Whenever applicable, utilize shaded areas in order to minimize the interference by sunlight.

Motive Settings

Increase the LED setting on the camera system to its maximum so that IR LED illuminates at its maximum strength. Strong IR illumination will allow the cameras to better differentiate the emitted IR reflections from ambient sunlight.

In general, increasing camera exposure makes the overall image brighter, but it also allows the IR LEDs to light up and remain at its maximum brightness for a longer period of time on each frame. This way, the IR illumination is stronger on the cameras, and the imager can more easily detect the marker reflections in the IR spectrum.

When used in combination with the increased f-stop on the lens, this adjustment will give a better distinction of IR reflections. Note that this setup applies only for outdoor applications, for indoor applications, the exposure setting is generally used to control overall brightness of the image.

*Legacy camera models

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