RFD 1083: The API avatar rig export contract
Problem
An upside-down rig, a backward-facing character, and a rig floating at the hips were real, repeated regressions from the Blender export path. Two sides, the client and the DGX API, each validated a rigged GLB independently, with no shared spec, so a fix on one side could still drift from the other.
Decision
One canonical spec, this document (mirrored at 3DAIGC-API/docs/API_AVATAR_RIG_CONTRACT.md, kept in lockstep), for every skinned humanoid GLB export: Y-up, -Z forward, feet on the floor, applied transforms, hips near mid-torso height. Both sides log [API-Contract] PASS or FAIL. The API fails the job outright on a critical code (upside down, facing backward, no skinned mesh, too few joints); the client applies only targeted skinned-mesh repair, and never reuses VRM-loader flags on an AIGC GLB, since a VRM upload and an AIGC rig follow deliberately separate paths (RFD 1104 gives the VRM side).
See DETAILS.md for the coordinate system, the full requirement and failure-code tables, the Blender export steps, and the retest procedure.