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fix: run reach-IK before the floor safety clamp (levitating cobra) #27

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Merged
a-baran-orhan merged 1 commit into from
Jul 10, 2026
Merged

fix: run reach-IK before the floor safety clamp (levitating cobra) #27

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15 changes: 13 additions & 2 deletions packages/posecode-render/src/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -346,8 +346,12 @@ export function createViewer(
effector: THREE.Object3D,
): THREE.Vector3 | null {
if (target === "floor") {
// Rest the effector's MESH on the floor, not its bone origin: the hand
// mesh extends below the wrist bone, so a bone target of y=0 would sink
// the palm and force the floor safety clamp to lift the whole body.
const p = effector.getWorldPosition(new THREE.Vector3());
p.y = 0;
const box = new THREE.Box3().setFromObject(effector);
p.y = Number.isFinite(box.min.y) ? Math.max(0, p.y - box.min.y) : 0;
return p;
}
const anchor = propAnchors.get(target);
Expand Down Expand Up @@ -458,6 +462,14 @@ export function createViewer(
depenetrate(mannequin);
applyGroundLockTo(mannequin, info.groundLock, frameAnchors(info.rootYaw, info.rootOffset));
applyPins(info.pins);
// Reach-IK BEFORE the floor safety clamp. When authored FK pushes a
// reaching limb through the floor (cobra: prone + shoulders flex 50),
// the limb must bend to meet the floor. Running reaches after the clamp
// let the clamp "solve" the penetration first by hoisting the whole
// rigid body into the air — legs floating, the classic levitating-cobra
// bug. Ground-lock and pins have already fixed the root placement that
// floor/landmark targets resolve against.
applyReaches(info.reaches);
// Safety net: nothing above ever intentionally pushes part of the body
// below the floor, so clamp the root up whenever the lowest point dips
// below y=0, a no-op whenever the pose is legitimately grounded or
Expand All @@ -473,7 +485,6 @@ export function createViewer(
mannequin.root.position.y -= box.min.y;
mannequin.root.updateMatrixWorld(true);
}
applyReaches(info.reaches);
if (info.phaseName !== lastPhaseName) {
lastPhaseName = info.phaseName;
phaseCb({ phaseName: info.phaseName, ...(info.cue ? { cue: info.cue } : {}) });
Expand Down
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