A 100-line Vista gadget that grew into a full-body mocap studio

What it does XR Animator turns a single webcam into a full-body motion-capture rig, driving MMD or VRM avatars in real time for VTubing and XR work. It runs as a web app in any modern browser or as an Electron app on Windows, Linux, and macOS, with face, body, and hand tracking via MediaPipe and TensorFlow.js.

The interesting bit The project began over a decade ago as a ~100-line JavaScript desktop gadget for Windows Vista: an animated anime girl that doubled as a CPU meter. The author kept bolting on features—music visualizer, MMD support, RPG engine, AR mode—until the codebase became, by their own admission, “outdated, clumsy and confusing.” They openly chose not to rewrite it, citing the programmer’s maxim: “If it works, don’t touch it.”

Key highlights

• 60fps 3D rendering and 30fps pose detection on modest hardware (GTX 1650-class)
• 52 ARKit-compatible blendshapes for “Perfect Sync” face tracking
• Exports mocap to VMD, BVH, and glTF; converts FBX/BVH to VMD
• VMC protocol support for piping animation to VSeeFace, VNyan, Warudo (Electron only)
• AR mode on Android Chrome via WebXR and ARCore
• Can run as a transparent, frameless window for OBS capture or as a 3D Windows wallpaper
• Web app works on desktop and smartphone; Electron build adds native-only features

Caveats

• The author explicitly warns the codebase is “incomprehensible” for anyone trying to build on it
• CC BY-NC-SA 4.0 license applies to source adaptations; generated content (your mocap recordings) is yours
• Project sustainability is uncertain; author cites financial pressure and minimal return

Verdict VTubers and indie XR creators who need accessible, low-cost mocap should try the web demo immediately. Developers looking for a clean, extensible foundation to build upon should look elsewhere—the technical debt here is architectural and acknowledged.