Character Rigging

The execution model is in blender-core. Faces and shape keys are in blender-facial-shapekeys, animation in blender-animation.

Pipeline (scripts chain; each returns JSON)

1. Prepare the mesh: scale applied, facing -Y, feet at Z=0, centered on X=0, symmetric, in T- or A-pose (A-pose 30, 45° deforms shoulders better). Run blender-asset-qa first.
2. Metarig: scripts/rigify_build.py -- --add basic_human --fit Body (human adds a full face rig; for games use --no-face + shape keys).
3. Place the joints (the fit only scales). Edit bones in X-ray against the mesh: joints sit at the pivot of rotation (inside the volume, not on the surface). The elbow and knee need a slight bend toward their natural direction (elbow back, knee forward) so the IK solves the right way. Symmetrize: bpy.ops.armature.symmetrize(). Check with look (shading="xray").
4. Generate: --metarig META_Body --generate gives RIG_Body (control rig: FK/IK, IK/FK snapping, tweak bones, bone collections).
5. Skin: scripts/bind_mesh.py -- --armature RIG_Body --meshes Body. It uses heat weights, switches to the voxel-proxy transfer automatically when heat fails (non-manifold, kitbashed or AI meshes), then cleans to 4 influences and normalizes.
6. Stress test: scripts/stress_poses.py -- --armature RIG_Body, then look(mode="frames", frames=[1,10,20,30,40,50]). Fix collapsing elbows, candy-wrapped forearms, a sunken shoulder or a hip crease (below).
7. Engine skeleton: rigify_build.py -- --rig RIG_Body --game-skeleton gives GAME_RIG_Body = root + DEF bones in a clean hierarchy, with DEF- stripped, constrained to the control rig and with the meshes re-targeted. Animate with the control rig, then bake to the game skeleton and export it (blender-animation → blender-export-pipelines).
8. Validate: scripts/rig_check.py -- --armature GAME_RIG_Body --profile unity|unreal|roblox [--fix].