Fix: Godot Skeleton3D Modification Stack Empty

An IK foot solver added to the Skeleton3D’s modification stack has no effect. The stack is created but not enabled, or the modification points at a non-existent bone.

Enable the Stack

var stack = SkeletonModificationStack3D.new()
stack.enabled = true
stack.set_skeleton(skeleton)
stack.add_modification(ik_mod)
skeleton.set_modification_stack(stack)

Without enabled = true, the stack is ignored. Without set_skeleton, modifications have no target.

Bone Names Must Exist

IK chains reference bones by name. A typo (or a bone renamed in the rig) silently disables that modification — check the editor warnings or query find_bone first.

Execution Order Matters

The stack runs modifications in order. IK after animation pose, look-at after IK — reorder so each modification reads the right input pose.

Verifying

Toggle the IK target and watch the bones respond. Animations play, then IK overrides the relevant bones each frame.

“Modification stacks need enabled = true, the right skeleton, and existing bone names.”

Drive modifiers via a single GDScript helper instead of via the inspector — easier to debug when bone names change.