Exporting bones to fbx with animated scale distorts transformations
Closed, ArchivedPublic

Description

System Information
Win 7 x64
Ubuntu x64

Blender Version
Broken: 794311c 457596d
Worked:

Short description of error

If the bones(even unparented) have some scale animation when are exported to fbx, the transformation of the bones are distorted respect the original armature.

Exact steps for others to reproduce the error


1 - Select the original scene chain, (it has all transformations bake)
2- Export as fbx
3- import the fbx

Details

Type
Bug

Yes, the problem appear only when the bones have animated scale.

I can make a video demo if you want it.

Bastien Montagne (mont29) triaged this task as Normal priority.

Weird, as if scale was applied more than once…

That’s actually sort of a limitation of the format… thing is, when you export an armature not binded to any mesh, we do not have any bind data in FBX file - and bind data are closest thing we have to 'rest pose' of the armature, i.e. state in which bones are assumed to be by default. So when we re-import such FBX, we only have the current pose of the bone at save time to rebuild the armature - which leads to deformed (too or too short) ones. Then animation is applied on top of it, which was saved for actual rest pose…

Not sure we can do much here really, only way I can think to work around it is to bind the armature to a dummy mesh for the export, and get rid of that one after importing the BFX…