An arm that twists badly can have a skinning defect, an orientation problem or an imported-motion mismatch. Test the unretargeted rig first so you do not repair the wrong stage of the pipeline.
Split the failing movement into two tests
Create a bend-only pose with little forearm rotation, then a rotation-only pose with a mild bend. Compare the mesh in each. If only imported animation fails, replay a locally authored pose before changing weights.
Keep the rest pose and original file intact. Bone orientation changes can affect existing animation, so they deserve a controlled experiment rather than an undocumented production edit.
Inspect orientation before smoothing everything
Display the relevant bone axes and compare their orientation along the limb. Check how the rig distributes rotation, including any intended twist helpers. A control-rig design may manage this differently from the exported deform skeleton.
If the rig behaves as intended, inspect the local weight transitions. Smoothing can improve an abrupt transition, but it cannot establish a missing retarget mapping or reproduce a constraint that never reaches the engine.
Compare the destination result
Bake a short diagnostic action through the intended export path. If Blender looks correct and the engine does not, inspect the exported skeleton, animation and retarget setup rather than continuing to repaint the source mesh.
Keep a short note describing which test failed and what change fixed it. That evidence prevents the same symptom from being given a different speculative fix on the next character.
For the bigger picture, use our free Rigify migration workflow and three-engine import test plan.
Official references and scope
Sources checked October 18, 2026. Interface names and capabilities can change; use the documentation for your installed version. The workflow above is an editorial checklist, not a published hands-on benchmark.
