When using the Roblox Animation Editor, I like to make use of IK. There is however an inconvenient bug, which is at least easy to circumvent. The way the bug manifests is that every other activation of IK, the controls are not set up properly and when you try to move the body part, it shifts the body part clean off of the rest of the rig. To remedy this, move the body part a tiny bit in the broken state, then disable and re-enable IK and it should work again.
Step-by-step description:
- Open “Manage IK” tab in Animation Editor and Enable
- IK will work as expected
- Disable IK
- Enable IK again, this second time around it doesn’t work.
- When you try to move a body part, it becomes disconnected from the body.
- Disable IK, enable it again
- Body part should snap back into place and IK works as normal again
This repeats every alternate time you enable IK.