Whenever tracking fails, ensure you are following the best practices outlined in the Tips of Markerless Tracking document🔗.

Here are some initial suggestions:

• Ensure the entire subject is visible and in frame thorughout the tracking interval. If part of the subject’s body is cut off, tracking will not work.
• Ensure there is only one subject in frame or that no other people are visible in the background.
• Ensure adequate contrast between the person and the background, and adequate lighting.
• Ensrure the camera is set up perpendicularly to the movement to reduce parallax error so accurate angles can be captured. For more details on the importance of camera setup as it relates to parallax error, review the Understanding the Limitations of 2D Video Analysis vs. 3D IMU-Based Motion Capture article🔗.