Importing as a skeletal mesh changes the normals or smoothing of objects

Hey,

There seems to be something wrong with the import process where face normals or smoothing groups are being affected by importing a mesh as a skeleton. Is there any way this can be corrected and solved?

  1. Shows the mesh imported as a static mesh and the face normal/smoothing work correctly with the normal map

  2. Shows the mesh imported as a skeletal mesh with no skeleton exported with the mesh from 3ds max

  3. Shows the mesh imported as a skeletal mesh with a skeleton and morph targets applied from 3ds max

Thanks for any help.

Dan.

Hi, I would be really grateful for some advice.

Faced with the same problem Skeletal mesh smoothing groups problem - Rendering - Unreal Engine Forums

Anything? Anyone?
I imported one model, both, as a static mesh, and as a rigged skeletal mesh. Skeletal mesh seems to have some weird problems. The issue is well described above in the question and no answer for such a long time? Whatā€™s the workaround?

Have the same issue, trying to find a solutionā€¦

I forgot to mention Iā€™m working currently on 4.19. Is it fixed on 4.20?

Guys, I probably found out whatā€™s the case! Itā€™s easy to fix!

I always ignored the error message when importing any FBX file, because it was always there and it didnā€™t do anything. Here is the message:

No smoothing group information was
found in this FBX scene. Please make
sure to enable the ā€˜Export Smoothing
Groupsā€™ option in the FBX Exporter
plug-in before exporting the file.
Even for tools that donā€™t support
smoothing groups, the FBX Exporter
will generate appropriate smoothing
data at export-time so that correct
vertex normals can be inferred while
importing.

Well, it tells the exact problem we have.
Iā€™m using Blender so Iā€™m sorry for not delivering the answer for 3d Max. I believe you will find it in your program too!

So, if you use Blender, when exporting FBX file, there are settings which looks like that:

254786-normals.png

Just change ā€œSmoothingā€ from ā€œNormals onlyā€, to ā€œFaceā€ (or ā€œEdgeā€ if you need).

I hope it will fix it for you. Let me know!

Check out my answer guys! Hope it works for you too, let me know because I could forget about something. If so, I will correct the post.

Hey thank you very much! I was using maya but tried this in blender and it worked. Now have to figure out how to do it in Maya. Iā€™ll keep here posted.

Hey, Ive looked into the FBX exporter in 3ds max and the only option for controlling smoothing is to export with ā€œsmoothing groupsā€. Its worth noting that do not get these import messages saying ā€œNo smoothing group information was foundā€.

Found some more information, another person with the same issue. 3dsmax doesn't export mesh normals on models with skin modifier ā€” polycount

Nope, Ive tested on this version.

Did you ever get to the bottom of this?

Did it help you then? Btw. you can always export to FBX/obj and generate smoothing groups in Blender! Blender is a free tool. I know it would be annoying as a workflow but thatā€™s a working solution for now. Better if you find how to generate smoothing groups in 3D Max, for sure. Good luck.

Thanks for the reply. The setting export with smoothing groups has always been set on as thats always how you should export from max (so made no change for me). That is an option (blender), but to switch at this stage would be very difficult, we have morph targets set up and i think it would be a massive pain.

Iā€™m running into this same issue in Maya2016 and UE4.2.1. No matter what we do any custom normals are blown and recalculated whenever the mesh is a skeletal mesh. If we unbind skin and export it as a static mesh with custom normals it works fine.

It seems like a bug, but Iā€™m not sure if itā€™s in the FBX exporter or if itā€™s the Importer in Unreal!?

It would be great to have some devs look into this and get it working.

Iā€™ve done some more research into this issue and have found that this problem seems to be on unreals end. Please look at my images. When importing a box as a static mesh vertex normals look correct and normal. In a flat side view you can see that the vert normals on each vert line up and look consistent. When importing as a skeletal mesh the vert normals visibly shift direction and no longer line up and donā€™t look consistent. The vert normals on the skeletal mesh should look the same as static mesh but they donā€™t. If I import the skeletal mesh but un tick the skeletal mesh option the mesh imports correctly, this makes me think this is not an issue with 3dsmax.

Using import normals on both meshes - Using anything else for a normal workflow does not work

I run into the same issue in Maya and Max, even with the smoothing group option checked on in the FBX export settings.
Weā€™ve tried it with newer and older versions of FBX and we get the same results each time.

Using blender isnā€™t an option for us, I really wish we could get this fixed we have some very ugly seams that donā€™t need to be there.

Hello Folks, checking smoothing groups and triangulate mesh works for me. Reason for that is, that the triangulation (and with that the smoothing) differ in unreal to other aplications.

Ive had the same problem for a while now BUT i think iā€™ve found a fix.

Im a Maya user, so when im Exporting an FBX for a skinned asset, be sure to have triangulated on and smoothing groups. ( as mentioned above posts ) but in Unreal when the import Box comes up look for " Normal Import Method " - change it to " Import Normals" ( which will read the normals from the imported FBX )
I think by default its set to " Compute Normals " which will let Unreal make its own Normals up ( which is why they look ā– ā– ā– ā–  on import )

This has sorted my problems, hopefully it will help you too.
GoodLuck!

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