rig asset type

• rig.json — the readable skeleton document, the asset's primary. Consumers reference the .rig asset's guid, never this inner file. It holds:
  • bones — ordered bones, each with a name, a parent index (-1 for a root), the node index it maps to, its rest local transform (translation / rotation / scale relative to the parent — the bone's offset and length), and its inverseBind matrix (16 floats). The inverseBind is what skinning reads.
  • bind — where the rig's bind pose, the pose retargeting reads anatomy from, comes from: "skin" (its inverse binds are a skin's bind, as a model import writes), "rest" (it has none: its inverse binds restate its rest, as an animation-only import's rest is the clip's first frame), or { "__ref": <rig guid> } (a skinned rig of the same skeleton whose bind it shares; an animation-only import names one when the world holds it). A rig with no bind reads its own inverse binds.
  • overrides — what an author set by hand, keyed by avatar type guid: { [typeGuid] = { roles = { [role] = boneName | false } } }. false leaves a role empty. Carried across a re-import of the rig's source file.

The format is JSON, not binary, because a rig is small structural metadata an agent inspects and corrects — the bulk binary .mesh/.animation carry their own decode paths, but a rig is meant to be read.

How a rig maps onto an avatar type

Which bone is the hips, the left hand, a hair strand, is derived from the bones whenever it is asked for, by the avatar type (see the avatarType asset type) — never stored. The skeleton's structure decides it, for any naming and in any pose the rig rests in, and the author's overrides are laid over the result.

local rig = asset.resolve(rigGuid, "rig")
local q = rig:qualify()              -- the builtin humanoid type; pass another type to ask it
print(q.qualifies, q.reason)         -- whether it is a humanoid, and why not
print(q.mapping.roles.hips)          -- the bone filling a role
print(q.report.verdict, #q.report.stale)

A skinned .mesh references a .rig (the mesh keeps only per-vertex skin weights; the skeleton lives here). An .animation references its source .rig. Retargeting maps a clip from its source rig onto a body's rig through the roles both rigs fill.

In the Inspector

Selecting a rig opens its Skeleton section: the bone count, the number of roots, whether the rig qualifies as a humanoid with its verdict and confidence, and the bone hierarchy, indented by depth.