When exporting a Skeletal Mesh from Maya to UE4, the vertex weights seem to have changed or something wrong has occurred during export/import?

[Artdabbler]

I’ve been having this problem for a while. It seems the weights on my geo change, or something occurs during Maya export or UE4 import. I’ve attached a jpg to show what I mean.

The 1st image is of my original Maya scene. The wrist looks fine; but once I bring the skeletal mesh and animation in to UE4, the wrist starts to collapse and pinch in on itself. I was wondering if anyone else has had a problem with import/export from Maya to UE4, or if this is a weighting issue of some sort? I also did export the skeletal mesh from UE4 to see if it’ll look the same back in Maya. In the 4th pic, you can see the skeletal mesh has indeed changed somehow during export/import.

Things that I have tried.
-Making sure there are only 4 or less joint weights per vertex.
-Check to see if the total vertex weights of each vertex equals one.
-Check to see if there are no joint vertex weights less than the value of 0.0001
-Exporting from Maya with FBX version 2014/2015 and 2016.
-Exporting from Maya with FBX type ASCII and Binary.
-Importing to UE4 by checking on/off each of the parameters.

Any help would be much appreciated Thanks!

Oh, I’ve also made a simple test with a cylinder and a 3 joint chain. Where joint2 is rotated in the x by about 150 degrees after rigging.

One thing to note. Both tests were done with Maya’s default rigging set. Using ‘create joints’ & ‘bind skin’ tools. I didn’t use UE4’s ART tool for Maya.

[anonymous_user_2ed5b4c7]

I think your problem is that UE4 not support Dual Quaternion mode as MAYA. UE4 uses fast and cheaper Linear mode. When you add skin modifier for your character, you need set “Skinning Method” to “Classic Linear” and to tweak the weight of vertices.

Also you can to use solutions from these tutorials. These tutorials about how to avoid twisting of the skin.

[Artdabbler]

svv3dUDN - THANK YOU SO MUCH! I’ve been racking my brain on this forever. That’s exactly the problem! Thank you also for helping me with a solution.

[ianbercov (array)]

Does anyone know the answer to this question?

If I import a skeletal mesh with dual quarternion skinning into UE4, will ue4 automatically treat that as linear classic or do I need to go into software like maya and change the skin blending to classic linear?

I know ue4 does not support DQ so that’s not my question. I just want to know if it’s ok to import DQ and UE4 will just convert it or if that might mess something up?