Blender rookie here. I'm learning about baking normal maps in 2.80 with some pretty basic setup.
I'm getting strange results on a smooth metallic flat surface. You can see it on the following screenshot. I'd expect the surface to be completely smooth, but it looks sort of like alligator skin or something :). Any idea what can cause it?
Things I did (roughly):
- Created a low-poly cube and UV unwrapped it (for this basic example I assumed "Smart UV project" is good enough) onto a 4K image (seems like overkill but I thought the problem originates from too low resolution - it doesn't seem to be the case though).
- Created a high-poly copy with Bevel, Subsurf and a slight Displacement modifiers, which I then applied.
- Set Smooth Shading on both objects.
- Added material to low-poly cube (metallic) with Texture Image node (Color space: Non-Color).
- Baked normals from hi-poly to low-poly.
- Saved image, selected it in Texture Image node and connected the node to Normal Map and then to Principled BSDF's normal input.
Things I tried: Adding more detail (loop cuts) to the hi-poly doesn't fix it. Setting resolution of normal image to 4K didn't help either.
Here's the complete .blend file with the normal map image: cube.zip
Thanks in advance.
After attempting to UV unwrap the low-poly mesh according to hatinacat2000's answer below, I ended up with following normal map:
However, baking that in did not remove the weird effect. To be sure, I mean that the metallic cube looks like there's some transparent net spread over its sides, not the displacement which I applied intentionally on the hi-poly mesh, and it seems to work fine.