Author Topic: Wrong Normals if UV shells not aligned  (Read 591 times)

Hi there,
I have a serious problem with normals.
I realised because I was texturing a really basic object.
But in order to see exactly what the problem was, I made a simple plane with some divisions and laid out the UV coordinates. Then I took random shells and rotate them 90º:



And exported an FBX with the following settings (pretty standard):



So it looked like this:



Then in painter, I baked all maps and just put a simple fill layer in order to make the object shiny and a bit rough:



As you can see, there are seams between the shells, which are NOT supposed to be. The orientation of the UV shells SHOULD not make any difference, shouldn't they?
And then, I left the shells orientation as they were before rotating them, and you know what?, it now looks correct:



What the hell is going on here?

You have both FBXs attached if you want to test for yourself.

Thanks in advance for any clarification. Surely I am doing something wrong, but I can't imagine what.

This is expected, this is a limitation of our realtime shader rendering.
You can minimise the effect of this issue by increasing the quality setting in the shader parameters, but this may impact the viewport performances.
Don't forget your log file. It can be exported from the Help menu of the software.
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Froyok aka Fabrice Piquet, Technical Artist and Product Designer at Allegorithmic.

Mmm, yes and no.
Boosting the quality settings actually fixes the shading seams, but not completely.
And, in fact, those seams are affecting generators. Here you can see the actual object I try to texture, with a generator applied to a layer's mask. The curvature is affected by the UVShells, and shouldn't. Curvature should only be affected by polygon continuity, ONLY.
So I ask again..., what the hell is happening here? (red arrows shows where the mesh UVs are splitted into UVShells):


The curvature issue is another subject, it's unrelated to the shading issue. :)
Currently our baker use the baked normal plus the low-poly to generate the curvature, it works most of the time but it's not perfect.

To get an accurate curvature it should be baked from a high-poly mesh and currently this baker is only available in Substance Designer. In a near future it should come to Substance Painter as well. Right now the current baker is quite sensible to UV seams and shell orientation because of how it reads the normal map.
Don't forget your log file. It can be exported from the Help menu of the software.
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Froyok aka Fabrice Piquet, Technical Artist and Product Designer at Allegorithmic.

Mmm, for that particular object I am not using any low poly, I am using the same object for baking everything.
Are you saying I have to bake with designer instead?

Mmm, for that particular object I am not using any low poly, I am using the same object for baking everything.
Are you saying I have to bake with designer instead?
Even if you don't use an high/low poly mesh workflow, you would still need a different baker to get an accurate curvature map. So yes if you want better results you will have to bake in another application (such as Substance Designer).
Don't forget your log file. It can be exported from the Help menu of the software.
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Froyok aka Fabrice Piquet, Technical Artist and Product Designer at Allegorithmic.

Thank you very much for that info. Disappointing, but helpful.