by theartful·VFX
Images © theartful. Used for product review; image policy.
Polychase earns its place in the blender_extensions library as a free, open-source motion tracking addon inspired by KeenTools GeoTracker, built on a C++ core with native Blender integration.
Polychase is a free and open-source motion tracking addon for Blender, inspired by KeenTools GeoTracker. It is a 3D motion tracking solution that lets you track camera movement or object motion in video footage inside Blender, combining optical flow analysis and PnP with user input for the results.
The workflow runs through the Polychase panel in the 3D viewport. You import footage as a movie clip, assign geometry and a camera, then analyze the video to generate optical flow data. In pin mode you place tracking points on the geometry surface and drag them to adjust the pose, then run tracking forward or backward to generate keyframes. A refine sequence tool improves accuracy using bundle adjustment, and animation can be converted between camera and object tracking.
Under the hood, the tracking algorithms are written in C++ with pybind11 bindings for Blender, optical flow comes from an OpenCV solution, PnP solves camera pose, and Embree accelerates mesh ray casting. The interface uses native Blender panels and operators with color-coded pins, wireframes, and progress indicators.
Polychase is best for blender artists doing 3D motion tracking who need to solve camera or object motion from video footage.
Polychase is completely free to download and use.
Polychase is compatible with Blender 4.2 LTS and newer. It can be added by dragging and dropping into Blender or through Install from Disk, with separate builds for Windows, macOS Apple Silicon, and Linux. Once installed, you open the Polychase panel in the 3D viewport, create a tracker, and assign your movie clip, geometry, and camera before analyzing the video and entering pin mode to place tracking points.
Polychase provides builds for Windows, macOS Apple Silicon, and Linux, each with its own download. The addon can be added by dragging and dropping into Blender or installing from disk. The tracking algorithms run from a C++ core with pybind11 bindings for Blender compatibility, optical flow comes from an OpenCV solution, PnP solving estimates camera pose, and Embree accelerates mesh ray casting during tracking.
Polychase is listed as free here and is released as free and open-source software under the GNU General Public License v3.0 or later. For current licensing terms and the source code, check the developer's page on GitHub, where you can also report issues and download the addon builds for each supported platform. Inspired by KeenTools GeoTracker, it offers a free, open-source route to 3D motion tracking in Blender.
Polychase requests file permission to write its optical flow database to disk, the only permission the extension lists. Before tracking, you set a database path and run Analyze Video to generate the optical flow data the tracker relies on. That data feeds the PnP solving for camera pose estimation and the bundle adjustment used to refine trajectories, which together produce and improve the tracked keyframes.
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