Joint.component

Typed body references, local frames and angular/linear constraint limits.

separateLinearFrame enables an independent parent orientation for the three linear constraint axes: linearFrameBX/BY/BZ/BW is a unit quaternion in body B's authored frame. The angular axes still use frameBX/BY/BZ/BW. When disabled, linear axes follow the angular frame, preserving existing joints. JSON callers use optional linear_rotation_b; omission uses rotation_b. Both frames are converted through the body's mass frame before solving.

The reconstructed character requires this distinction for all22 skeleton joints. The private121frame reference comparison checks every consumed frame word and the full96word constraint workspace for all2662joint states. Two unused anchor padding lanes are excluded from frame-byte comparison (native signed zero there does not enter the decoder); constraint workspaces still match bit-for-bit. This verifies joint-frame representation, not complete character simulation.

Angular modes and independent speed limits

free permits all angular directions selected by the joint. Native swing mode 3 is exposed as hinge, not free: it retains a constrained perpendicular axis. limited_hinge preserves native swing mode 2. Stock board wheel joints explicitly use hinge and retain their original speed allowances.

Angular velocity allowances are independent relative-speed limits in radians per second. Zero is a zero-speed limit, not an unlimited value. New generic joints default to 1,000,000 rad/s so an open angular limit does not accidentally act as a brake. Explicitly authored values (including zero) remain authoritative.

Migration: stock-board definitions using the former free spelling for native mode 3 must use hinge. Rebuild the provided scene after changing the kernel and component together. Old generic joints with explicit zero velocity allowances must be reviewed; do not overwrite intentional speed limits automatically.

Native rider slots

A Joint beneath NativeRiderDriver.constraintsRoot may reference two rider NativeActorPart entities from the same physicsRoot. Set world to that physicsRoot and nativeRiderSlot to 0..21. readRiderJointDefinitions() on a ready driver returns the current slot, endpoints, anchors and frames for authoring. Body A is the native child and body B its parent. Preserve the separate linear frame when copying definitions. Each slot may have one override; other slots remain native.

nativeRiderAngular defaults to native: mode-dependent normal/ragdoll angular settings still come from the native owner. Select authored to use this Joint's angular fields instead. nativeRiderEnabled=false suppresses that slot's rows. Deleting the override restores the native slot. These edits survive R recovery. Animation drives remain active and can resist contradictory anchor edits. Mixed board/rider endpoints are explicitly unsupported by this adapter.

A copied default slot passed the full 520-frame Zero replay unchanged. A 20 mm anchor edit produced approximately 19.1 mm in the ragdoll test; native mode limits, authored angular values, disabling, reset and restoration were checked.