> For the complete documentation index, see [llms.txt](https://docs.theiamarkerless.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.theiamarkerless.com/theia3d-documentation/object-tracking/overview.md).

# Overview

Theia3D Object Tracking enables people and object tracking to be integrated in a single markerless motion capture workflow, without the need for sensors or instrumentation. It enables team-scale, real-environment data capture of human biomechanics with coupled Linked Object trajectory tracking and independent Free Object trajectory tracking. These features can be included in the analysis for automated, simultaneous tracking of people and objects. 

This capability is offered as an add-on package to the core Theia3D license.

#### Linked Object (Bat) Detection and Tracking <a href="#bat-detection-and-tracking" id="bat-detection-and-tracking"></a>

Theia's Linked Object tracking identifies several points on each object to capture detailed motion and trajectory throughout the trial. Each linked object must be associated with a tracked athlete by definition.&#x20;

The baseball bat linked object is tracked using the base and tip landmarks, and as a result does not convey meaningful information about the axial rotation of the bat. The bat segment coordinate system is located at the base landmark.

#### Free Object (Ball) Detection and Tracking <a href="#bat-detection-and-tracking" id="bat-detection-and-tracking"></a>

Theia’s Free Object tracking identifies all balls visible within the capture volume, with options to track only a single moving ball and/or to remove all stationary balls for cleaner data. Balls are tracked as Free Objects, meaning that they are independent objects and do not need to be associated with an athlete who is tracked during the movement trial.


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