Exporting Skinned mesh will recompute vertex normals

[Anonymous]

Hi all,

when exporting skinned mesh using fbx, it seems to re-computes the vertex normals. Is there a way to keep the edited vertex normals on a skinned mesh when exporting thru fbx?

In the attached pics, i've 2 sphere geometry, both with the vertex normals edited the same way. The left one is skinned to a joint. They are exported as fbx, and when re-import into maya, the skinned mesh's normal got recompute. Am i exporting with the wrong options? any help would be appreciate. Thanks.

[sean.heasley]

Hi @Anonymous

It looks like they aren't being saved somehow, have you tried locking the normals before exporting?

If that doesn't work, you could try toggling split per-vertex Normals on the export settings to see if that changes anything.

Please let me know if this helps or if you need any more assistance!

If one or more of these posts helped answer your question, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

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[Anonymous]

Hi Sean,

Thanks for the quick reply. I "think" i found the problem. Seems like the edited vertex normal do get saved into the fbx file, and if i import that fbx into Ue4, the normals looks like how i would expected them to look. The issue seems to be when importing that exported fbx file back into maya(as i usually tried to delete some extra objects that comes with the rig before going into ue4). I tried changing up either the unlock normals or combine per-vertex normal options during import, but neither options changes the results. I also tried to lock or unlock the vertex normals before export as suggested, and the result is the same.

so for now i can get around the problem by doing my clean up before export. I just want to understand if there's a bug somewhere regarding importing skinned meshes with locked normals from an fbx file. So far it's 100% reproducible for me in maya 2018. just bind a sphere to 1 joint and edit the vertex normal, or tried to bind a skin to a mesh with edited/locked normals. Export that as an fbx and then try importing it back into maya. Seems like there's no way to get the edited vertex normal back into maya correctly from that skinned mesh.

thanks.

[sean.heasley · Accepted solution]

Hi @Anonymous

I just did some quick testing with your repro steps and it looks like this only happens when the Animation option is toggled.

If you uncheck Animation and export/import the vertex normals should look the same.

That said, this looks like it is indeed an issue with Maya and I went ahead and logged it with our dev team so they can work on a fix!

Please let me know if this helps or if you need any more assistance!

If one or more of these posts helped answer your question, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

Kudos are greatly appreciated. Everyone likes a thumbs up!

[Anonymous]

Any news? It's still not working

[Anonymous]

It's still a bug, and It's also in 3ds Max!!!

https://forums.autodesk.com/t5/maya-programming/a-bug-still-in-maya2022-zhi-daomaya2022dou-mei-you-x...

[chenxu.1070]

这么多年了，问题解决了吗？预计哪个maya版本可以修复此问题？非常期待更新！

[asocoba96]

Hello! I'm wondering if this problem is already solved. I am trying to export a skinned mesh with the normals averaged as an fbx, but I still seeing the same problem when importing the fbx back into Maya. I tried unchecking the animation and locking the normals, but it doesn't seem to solve it. Let me know if there is any way to solve it. Thank you!

[asocoba96]

Hello! I'm wondering if this problem is already solved. I am trying to export a skinned mesh with the normals averaged as an fbx, but I still seeing the same problem when importing the fbx back into Maya. I tried unchecking the animation and locking the normals, but it doesn't seem to solve it. Let me know if there is any way to solve it. Thank you!