There's a couple of possibilities why this might be occurring, I don't remember all the ones I came across but you can try: *When exporting animation, only select the bones. *When exporting models, select the geo and the bones or just the geo *Make sure that the skeleton you're animating is the same that your meshes are…
After using Reset X-Form I got the problem the impoted model is very very small. There were not getting smaller in Autodesk just after the import. Micro Ward: