Export models with mirrored UV sets & normal maps?

[Eric Cosky]

Hi,

I recently created a model that uses a mirrored UV set and it looked as intended in 3DCoat, with both sides of the model showing the normal maps correctly. When exported to Softimage, I found myself having difficulty getting the normal maps to look correct and I eventually found this to be the result of tangents somehow not getting set up or otherwise reaching Softimage correctly (the apparently typical problem with mirrored tangents flipping the normal map shading angle).

I have since been told that the obj format doesn't support tangent data, so this would explain part of the problem. I eventually wound up exporting half the model and doing the symmetry in Softimage which allowed it to work correctly. I'd like to avoid this next time around though, so I'm curious if anyone has had more success with FBX or LWO formats while using mirrored UV sets with normal maps. I made several attempts with those, but had the same results as the OBJ format. Maybe I missed something though. Anyone out there have better luck getting mirrored normal maps out of 3DCoat? It would be nice to know if there was a particular format known to export the correct tangent data for mirrored UVs.

Thanks for any feedback,