Introduction
This page is for collecting information about characters on the web, and for trying to line up the concepts with USD.
Well established technologies are linked here for reference, and the concepts used by characters on the web are listed.
Concepts
- Linear Blend Skinning
- Blend Targets
- Animated Texture Maps
- Proceduralism
- Look At
- SpringBones
- Cloth
- Hair
- Collision
- Spheres
- Cylinders
- Planes
- Animation Clips
- Weighted and Blended Animation Clips
- Accessories
- Skins
- Clothing
Concepts, In Detail
Blend Targets
In Unity it's an import choice to either import or calculate blend shape normals. Calculation is then "auto-smooth" per-blendshape and the calculated normals are used at runtime for interpolation.
Video of a box/sphere blend shape interpolation:
Which means that sharp cube to smooth sphere is representable in Unity and also in FBX and glTF
Mapping the Concepts to USD
Anyone available to have a go?
VRM
Next Gen Idol Master Graphics and Animation Programming Preview; https://cedil.cesa.or.jp/cedil_sessions/view/416
- From CEDEC 2010, the basics of what's in VRM are laid out
Kawaii Physics; https://github.com/pafuhana1213/KawaiiPhysics/blob/master/README_en.md
- Widely used in Japanese AAA games plugin for UE that implements secondary character animation
vrm-samples, https://github.com/madjin/vrm-samples
- VRoid sample models in VRM format
VRMToybox, https://github.com/Keshigom/VRMToybox
- browser based VRM viewer
VRM4U, https://github.com/ruyo/VRM4U
- VRM importer for UE4
VrmEditor, https://github.com/ousttrue/VrmEditor
three-vrm, https://github.com/pixiv/three-vrm/tree/dev
- reference implementation
VRM specification, https://github.com/vrm-c/vrm-specification
- specification
VRM consortium, https://github.com/orgs/vrm-c
- hosting for their various projects, including the specification
VRM documentation, https://vrm.dev/en/
- documentation published by the consortium