Non-compensated scale on a child joint makes its rotate wrong if parent joint has a non-uniform scal
I'm facing an issue on which I can't seem to find any answer (google/forums...) when it comes to import a quite simple setup :
One joint that has a non-uniform scale on it (like (0.7;1,2;1,3))
Its child joint, which rotates and doesn't have the option "Segment Scale Compensate" ticked in Maya (so the rotate will behave as "constrained" by the parent scaled joint)
It's for a simple eyeball, here's what you have in maya :
In FBX review (looks the same) :
In Unity (also matching 1/1) :
Now, fun stuff begins...
In Marmoset 3.08 (bad result) :
Which makes me a bit sad since in Marmoset Toolbag 3.03 I have a good result, as shown there :
And just in case : same issue found with UE4.25 (I've started a topic here : https://answers.unrealengine.com/questions/963699/view.html )
Any idea on why this seems no longer supported ? When it comes to animation, except in rare cases, I'm mostly sticked to 3.03 version which does the right job. 3.08 is superior for playback framerate, baking, rendering...but has too often issues with animated stuff. I hope this little example will help you troubleshoot this issue.
To reproduce, simply :
- create an eyeball (or any sphere with a recognizable shape on the surface so you can track deformations with ease)
- import this mesh in maya
- create then a super simple hierarchy : Root>Joint 1(name it "scale")>joint 2 (name it "rotate") (where ">" means "ancestor of")
- skin bind your mesh to the "rotate" joint
- on the rotate joint, deactivate the "Segment Scale Compensate"
- on the Root + "Scale" joint, activate the "Segment Scale Compensate" option
- Create a few keyframes on the "rotate" joint (only edit its rotate XYZ attributes)
- create a scale (non-uniform) keyframe on the scale joint. At this point you should have the maya/Unity/FBXReview/MT3.03 result. Export this
- Import this FBX into marmoset 3.08. Should give a wrong result as shown above
Not sure but since I'm getting weird result on my animated characters since the 3.04, maybe this issue was here since that build
Thanks for your time, and be sure Marmoset is still one of my favorite softwares 
Cheers
Replies
Thanks for your quick response ! You can get the FBX file from here : https://www.dropbox.com/s/b2zj8dez261r4zc/Non_UniformScale.fbx?dl=0
Appart from that, the amount of improvements is unbelievable, magic, awesome !! I can't tell how much I love how marmoset evolves, I wasn't ready for the "texture project" part, it's a fantastic and smart addition ♥
Keep up the good work guys, and I hope this scale problem will be fixed soon
Are your team planning on solving this bug one day ?
I'm also having a "single vertex with incorrect skinweights" issue (seems it goes back to the root). Maya, 3dsmax, blender, akeytsu, FBX review, sketchfab, unreal....all of them does not have the issue.
Happens since 3.04 (that's why I'm carreful with new versions since then when it comes to render animated stuff...I wish I could use the whole power of toolbag without fearing such thing, especially after all these years of reporting that same issue, still needing to use the 3.03 feels strange...)
Ow and, supporting camera import but not its FOV is also a strange mess...
exporting to alembic might be a solution until fbx gets fixed. It has its own issues, facesets (single mesh, multiple materials) come in swapped and vertex color doesn't work. I haven't tested this in 4.01 yet but I didn't see it listed as a bug fix so its probably still there.
Honestly, if I had only one shot to do I would spend time converting my file to other formats to find one that works but since I use toolbag intensively and quite close with everything I do in Akeytsu I'd love to keep the simple FBX bridge between these two apps. Not to mention that the FBX used is the same I send to 3DCoat, and possibly Unreal, Sketchfab...etc. Having too many files for such a tiny purpose would rapidly become a nightmare
I'll keep on waiting, but guys, this issue is there since 3.04... (2018-04, just in case. We'll soon reach 3 years)