Normal maps rendering wrong in Karma CPU

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hey folks
I've been pulling my hairs trying to understand what's happening here, and while I'm leaning toward a Karma bug, I thought I'd share the issue.

Basically in CPU mode, light seems to bleed through the surface when using a normal map, either with a principled shaders or using a materialX standard surface. This pic here is a simple materialX tree with a redish light under a grid :


However, XPU works fine :



Can't think of an explanation and for a lot of reasons I don't want to render in XPU mode on a CPU farm :p

For now my workaround would be to grab the bump map instead and add it to the displacement, but I'm not super satisfied with such a solution...
Any ideas?
Edited by Wolrajh - 2022年11月25日 07:18:46

Attachments:
nrmlmaps_A.JPG (170.8 KB)
nrmlmaps_B1.JPG (20.4 KB)
nrmlmaps_B2.JPG (29.6 KB)

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I experience the same thing if I set my area light to ridiculously high intensity and exposure. Modestly pushing the default light values still keeps things in check. Instead of using one extremely bright light, try using many lower intensity lights?

Attachments:
karma_cpu_normal.gif (423.0 KB)

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