WorkLink Create: Configuration and Best Practices for Object Tracking
The Object tracking feature allows users to align and track objects more effectively on the WorkLink App.
- Click on Window Menu > Asset Library > Upload Files to upload the 3D object to be used for object tracking.
- Click on Window menu > AR Trackers> Create AR Tracker to create an AR tracker.
- Click on Window Menu > Object Properties, then click on the AR tracker in the scene for further configuration.
- Click on the drop down arrow beside “Type” under “AR Tracker and choose “Object Tracker”.
- Click “Select Model” to choose the 3D object that will be used for tracking from the Asset Library. This is the 3D object that was uploaded in step 1 above. The model will be uploaded to the scene.
- Remember to upload the 3D object you wish to use for tracking in the Asset Library.
- By default, the auto - pose is enabled. This allows the user to look at the object from any direction and begin tracking.
- If Auto - Pose is disabled, Initial Pose can be configured. This allows you to define orientation and position i.e. the intended direction that the user will start tracking the object from. While defining an init pose, a user can:
- Focus on an object (hotkey "f", or focus icon)
- Change the gizmo to translate (hotkey "w", or gizmo translate icon)
- Change the gizmo to rotate (hotkey "e", or gizmo rotate icon)
- Do regular navigation (alt+LMB, alt+MMB, alt+RMB)
- Reset a pose to a default view (e.g. When a user wants to recover from an unintended state)
- Click "Cancel" to undo changes and exit the preview pose window.
- Click "Apply" to apply changes and exit the preview pose window.
- The edit init pose displays a square ratio, but this square will be cropped on the end device, depending on the aspect ratio it has. A preview of the aspect ratio crop is represented by the yellow dotted line as shown below. The yellow dotted line corresponds to the aspect ratio defined in the UI editor, as also shown below:
For a specific configuration, user can tweak the Advanced Object Tracking Settings. First, disable Auto -Pose and click on the drop down arrow for “Advanced Object Tracking Settings” to input required values.
These are important tips for good object tracking (these are recommendations/ ideal scenarios, not limitations, the more of these points are checked, the smoother the experience):
- The 3D object uploaded under “select model” needs to be an exact 3D model of the object that is being attempted to track in the real world. The accuracy of the 3D object vs the real life object is very important.
- Ensure that the 3D object is correctly imported. Meaning correct scale (meter size), correct rotation (right way up) and correct translation, before import. You can double check the size by importing the 3D object into a step and measuring it with the Tools - Distance Tool.
- Create some sequences and steps that match the position of your 3D model used for tracking.
- As this technology is comparing lines generated by edges (normals) in the 3D object with lines caused by contrast on the real world object, the object being tracked in the real world should be uniform in color on places where no edges are present. (eg. a camo print or development mule decals on an object would be the worst case scenario.)
- The lighting conditions in the real world should be optimised for optimal contrast recognition of shapes, so that edges can easily be detected. For this reason, over- or underexposed objects will be more difficult to detect (eg. a completely black object might be more difficult to detect edge contrast.)
- Using Auto - Pose disabled (Init - Pose enabled), you can define the angle the end user needs to position himself to initiate the tracking. This is ideally a position in which the object has recognisable features/contours.
- A good contrast of the real world object with its background is helpful. This helps to generate good contrast for edge detection (e.g. a mid grey object on a white background.)
Recommended settings for Advanced Object Tracking Settings
- The only setting you might need to adjust is the "Laplace Threshold" (as it is influenced by model size).
- You can roughly interpret this value as the maximum (width or height or depth) value of the 3D object bounding box (on condition the object is not positioned smaller within the "Pose preview" window as in the screenshot above).
- Integer values are fine (doesn't need to be 100% exact), round up when in doubt. (eg. max object size is 3.2 meters, use value 4. Any object smaller than 1 meter, use value 1.)
- After this is done, you can publish the scenario and try it out on your device.
Object Tracking was previously known as Model Tracking.