Main Page → Builder pane
The Builder pane is used for creating and editing trackable models, also called trackable assets, in Motive. In general, rigid body assets are created for tracking rigid objects, and skeleton assets are created for tracking human motions.
When created, trackable models store the positions of markers on the target object and use the information to auto-label the markers in 3D space. During the auto-label process, a set of predefined labels gets assigned to 3D points using the solver pipeline, and the labeled dataset is then used for calculating the position and orientation of the corresponding rigid bodies or skeleton segments.
The trackable models can be used to auto-label the 3D capture both in Live mode (real-time) and in the Edit mode (post-processing). Each created trackable models will have its own properties which can be viewed and changed under the Properties pane. If new skeletons or rigid bodies are created during post-processing, the Take will need to be auto-labeled again in order to apply the changes to the 3D data.
For creating rigid bodies, select the rigid body from the Type option and access the Create tab at the top. Here, you can create rigid body assets and track any markered-objects in the volume. In addition to standard rigid body assets, you can also create rigid body models for head-mounted displays (HMDs) and measurement probes as well.
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:
Defining Assets in Edit mode:
This feature can be used only with HMDs that have the OptiTrack Active HMD clips mounted.
For using OptiTrack system for VR applications, it is important that the pivot point of HMD rigid body gets placed at the appropriate location, which is at the root of the nose in between the eyes. When using the HMD clips, you can utilize the HMD creation tools in the Builder pane to have Motive estimate this spot and place the pivot point accordingly. It utilizes known marker configurations on the clip to precisely positions the pivot point and sets the desired orientation.
HMDs with passive markers can utilize the External Pivot Alignment tool to calibrate the pivot point.
You can also define a measurement probe using the Builder pane. The measurement probe tool utilizes the precise tracking of OptiTrack mocap systems and allows you to measure 3D locations within a capture volume. For more information, please read through the Measurement Probe Kit Guide
Note: Custom Probes
The Builder pane has tools that can be used to modify the tracking of a rigid body that's selected in Motive. To modify rigid bodies, select a single rigid body and access the Modify tab at the top. This will bring up the options for editing a rigid body.
This feature is supported in Live Mode only.
The rigid body refinement tool improves the accuracy of rigid body calculation in Motive. When a rigid body asset is initially created, Motive references only a single frame for defining the rigid body definition. The rigid body refinement tool allows Motive to collect additional samples in the live mode for achieving more accurate tracking results. More specifically, this feature improves the calculation of expected marker locations of the rigid body as well as the position and orientation of the rigid body itself.
The Probe Calibration feature under the rigid body edit options can be used to re-calibrate a pivot point of a measurement probe or a custom rigid body. This step is also completed as one of the calibration steps when first creating a measurement probe, but you can re-calibrate it under the Modify tab.
The Modify tab is used to apply translation or rotation to the pivot point of a selected rigid body. A pivot point of a rigid body represents both position (x,y,z) and orientation (pitch, roll, yaw) of the corresponding asset.
You can also use the Gizmo tools to quickly make modify the pivot point of a rigid body
The OptiTrack Clip Tool basically recalibrates HMDs with OptiTrack HMD Clips to position its pivot point at an appropriate location. The steps are basically the same as when first creating the HMD rigid body.
This feature is useful when tracking a spherical object (e.g. ball). It will assume that all of the markers on the selected rigid body are placed on a surface of a spherical object, and the pivot point will be calculated and re-positioned 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.
To create skeletons in Motive, you need to select the skeleton option from the type dropdown menu and access the Create tab at the top. Here, you select which skeleton markerset to use, choose the calibration post, and create the skeleton model.
The magenta markers indicate the segment markers that can be placed at a slightly different position within the same segment.
In Edit Mode
You can also select a skeleton and use CTRL + R hotkey to refresh the tracking of skeleton if needed.
Existing skeleton assets can be recalibrated using the existing skeleton information. Basically, the recalibration recreates the selected skeleton using the same skeleton markerset. This feature recalibrates the skeleton asset and refreshes expected marker locations on the assets.
To recalibrate skeletons, select all of the associated skeleton markers from the perspective view along with the corresponding skeleton model. Make sure the selected skeleton is in a calibration pose, and click Recalibrate. You can also recalibrate from the context menu in the Assets pane or in the 3D Viewport.
Skeleton recalibration do not work with skeleton templates with added markers.
You can add or remove asset model markers from a rigid body or a skeleton using the Builder pane. This is basically adding or removing markers to the existing rigid body and/or skeleton definition. To do this, you will need to make sure the selection of Asset Model Markers is enabled in the Perspective viewport. Then, follow the below steps to add or remove markers:
This feature works for skeleton assets only
For skeleton marker sticks, you can use the Builder pane to add/remove markers sticks and also modify the color of the sticks as needed.