I've been having a lot of trouble with getting curvatures to work correctly where the UVs/normals of my models are split. I'm not quite sure if this is user-error, a bug, or something that's just not supported, but it's proving to be quite a problem for me.
Originally I was having this on a larger and more complex model, but I made a very simple model to demonstrate the issue. I imported the model in Mixer and set up a solid black layer, plus a solid white layer above it with a stack mask. In the mask I have a curvature map. Here's the results, with cavities and edges separated for clarity:
It looks like a few things are going wrong:
- It's usually only one side of a seam that "sees" the seam; the other doesn't get any curvature.
- The curvature has missing portions of it across otherwise continuous edges of seams.
- Some seam edges are completely ignored.
If the faces are smoothed and the UVs aren't seamed, this doesn't appear to happen. Mixer identifies those edges perfectly fine. It seems to be the presence of two edges that aren't actually connected that causes the issue.
I saw some suggestions from staff here that this may be related to UV mapping. I tried several different approaches to unwrapping and all had some variation on this issue. I saw this page and tried to get as close as I could, but really, this test model is so much simpler it doesn't even look close to those. Some of the comments here related to the direction of the UVs, but I don't really understand what that translates to in a practical sense. Topology often limits the ability to control UV direction.
It's possible I'm doing that wrong, but if I am, it would be helpful to know exactly what. Here's the UV unwrapping in blender:
Here are the files involved - the object file blender exported and the original blender file.
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