(Blender) (TexTools) What could be causing these minor blotches in my normal map?
I'm modelling a sword blade, using TexTools to perform a bake. On the whole the bake behaves as I expect, but in some spots of the resulting normal map there are strange blotches where the normals are different.
The difference in values within these blotches compared to their outsides are very small- they're tricky to catch without multiplying the normal value several times. However, the borders defining the blotches are quite distinct, with no real gradation. Not something I would expect from some unanticipated ray projection error. Indeed the borders don't seem to correspond to any topology features in the high or low poly. However, they are mirrored along the symmetry of the blade.
Attached is a zip containing the blend file, which has the low/high poly set up. Below is a screenshot demonstrating one of the blotches in material view, but it might be very difficult to see depending on your screen setup. Does anyone have any idea what could be causing them?
Replies
my guess: image bit depth
Currently only on my phone i suspect that it might be related to 24bit or 8bit per channel image depth which was default until now in TexTools. The next update uses 32bit floats and therefore much higher precission. When saving for game engines though you might have to dither it.
More on that topic: https://www.cgcookie.com/articles/bit-depth-how-compression-affects-normal-maps