Curvature baking when using mirrored UVs?

[theschaeff]

Currently using version 2018.3.3 so maybe there's a workaround in newer versions and I'm happy to fork over the cash for the latest version if necessary.

I'm trying to bake curvature maps but my model uses mirrored/re-used UVs and I guess SP uses world normals when baking curvature maps so as you would imagine this makes the baked curvature map unusable wherever there are overlapping UVs. My first thought was to make the mirrored faces a separate material but unlike AO curvature does not bake between different materials. The only solution I can see is to manually splice together curvature maps which is about as far from ideal as I can imagine.

The UVs are overlapping sure but if you were to bake them out individually you would get the same results as the overlapping UV islands are always identical and their relative positioning to other geometry is always the same.

Re-using UV space is so common I can't imagine that curvature maps are just useless in these instances, right?

[michael_11]

I never encountered this issue, even if I am using mirrored UVs all the time. I would think, that SP bakes the curvature from the tangent space normal map (Designer has curvature from mesh bakers).
Obviously I always make sure to move the faces, which are re-using UVs, away from the 0-1 UV space, so they don't interfere with the bake.

Maybe you can give us an example as to better understand the problem?

[theschaeff]

Oh my god Michael you're a life saver.
I've never moved mirrored UVs outside the 0-1 range cause I thought it wouldn't make any difference since things tile anyways but I tried it and sure enough it works great! I guess in the past I mostly only ever baked things like tangent normal maps and AO so I never hit this wall before. Thank you so much

[michael_11]

cool, glad you got it sorted

btw, the best practise to move overlapping/mirrored faces to a different UV tile helps to avoid baking issues for all mesh maps. since the curvature is created from the normal map (not from the mesh), it is more of a secondary symptom.

some engines/exporters weld/merge overlapping UVs, which can cause additional issues for mirrored faces - so having them in a different UV tile is a good thing in this respect as well.