half of UVs messed up when exporting to FBX

[sonictk]

Hi everyone. I have a weird texture issue in Softimage.

When viewing my model in softimage, everything looks fine. However, when I export to FBX and re-import, half the model texture looks messed up; while the UVs look fine in the viewport:

http://i.imgur.com/TsnUB.jpg

When I look closely, I notice that the UVs have somehow been rotated in such a way that they look fine, but the edges are all rotated wrongly (the seams don’t match up anymore and I can’t island select areas)

http://i.imgur.com/fOvwr.jpg

Exporting to .obj doesn’t seem to give this issue, but this is not a good solution as I may need to animate the robot in the very near future...could anyone shed some light as to what I may be doing wrong here?

[Caveman]

From what I have heard it is a bug with the FBX exporter in Softimage 2012 and that It has been resolved in 2012.5 but from the screenshots above I can see that you are already using SAP. Double check if you have Installed Crosswalk 2012.5.

[sonictk]

I specifically installed 2012.5 Crosswalk before starting work on this as I thought it would help solve any silly animation issues that our small team would have down the road. I was wrong, but I didn't think that I'd have problems with just static meshes as well...

Also, some more info on the model (I was typing this at 4AM last night so I apologize if the post seemed kind of sparse):

- Model was done in XSI, and had hard edges marked.
- However, I exported it as obj and UVmapped it in headus UVlayout, then re-imported that obj back into XSI. Because I lost all my hard edge information through this process, I copy-pasted the new UVs from the newer obj to my original polymesh back in XSI.
- I tried using the standard Copy/Paste UVs function from the Texture Editor and GATOR. Both give correct results initially, but after the model is exported as FBX, both methods will produce the same UV-messing-up issue.
- I have gone through the entire hierachy and I can't find anything out of the ordinary.

http://i.imgur.com/oXWPe.jpg
Shows the model displaying correctly in the XSI viewport with the hierachy expanded. Everything is frozen, transforms are reset.

Update: Ok, this is weird. After some experimentation, I have fixed the issue, sort of, but I have trouble understanding why it would have worked.

What I did was apply GATOR again on the mesh that had problems, but which ALREADY had the gator operator applied to it and frozen beforehand, then export as FBX. Now the UVs seem to be fixed during export, but I have no clue why this would have worked. Would anyone be able to shed any light on this issue?

Also, I noticed that without any tomfoolery of the sort, if I just export the mesh as FBX without hard edges, the UVs will also not be messed up.

DOES NOT COMPUTE O__O

[j3st3r]

The issue might be that you have symmetrized polygons. With this, the order of the vertices is not understandable by the FBX exporter. Solution is to triangulate your model before you export, or try with the Collada exporter...

[sonictk]

The issue might be that you have symmetrized polygons. With this, the order of the vertices is not understandable by the FBX exporter. Solution is to triangulate your model before you export, or try with the Collada exporter...

Hi, thank you for replying! However, I am curious, if the polygons on one side were indeed symmetrized, shouldn't I be able to see such a property in the XSI explorer? I was trying to figure this out for the longest time.

[benoit81]

This bug has been reported :
WNCH-1438 FBX: Problem with texture coordinates in exported FBX

I think that it has not been fixed with 2012 SAP. I hope Autodesk team would manage to fix it in 2013.
A workaround : freeze your model before applying any symmetry. If you already have this bug : export/reimport .obj (it fix the mesh).

Kind Regards,