Dirt on normal map after baking

crocoraffe

Hi, this is my trouble. I am bake normal map in maya, and on finish i get this strange dirt on map. That effect does not goes away even if i change quality and resolution settings. I check colors with eyedropper tool in Photoshop and i see that dirt is a color difference on map for 1 or 2 from basic normal color. Substance designer and xnormal has the same problem on bake. I check meshes (two primitive cylinders, first lowpoly, second with smooth) with cleanup and meshes are ok. What i can do to fix this bug?

this dirt comes on different models that i try to bake

AdvisableRobin

What file type are you using? I believe this problem is due to color depth of certain file types being only 8bit rather than 16bit. So the stair stepping effect you are seeing is from there not being enough colors to represent the gradient.

Either bake it at twice the size and then take it into photoshop, convert it to a 16 bit image and then downsize it. Or try baking it as a .tiff

crocoraffe

AdvisableRobin wrote: »

What file type are you using? I believe this problem is due to color depth of certain file types being only 8bit rather than 16bit. So the stair stepping effect you are seeing is from there not being enough colors to represent the gradient.

Either bake it at twice the size and then take it into photoshop, convert it to a 16 bit image and then downsize it. Or try baking it as a .tiff

I bake it in tiff16 and try tiff, same result

p.s. i do what u say, the same result(

jfitch

I always see shit like that in maya. Try bringing it into your intended renderer and see if you have the issue.

Edit: can you post an image of your high/low poly and topology?

I'd also try baking as a tga, that seems to work for me though I'm not sure why.

crocoraffe

jfitch wrote: »

I always see shit like that in maya. Try bringing it into your intended renderer and see if you have the issue.

Edit: can you post an image of your high/low poly and topology?

I'd also try baking as a tga, that seems to work for me though I'm not sure why.

i think bug in software, cuz i bake it in 3ds max, and normal map seems pretty clean and good

EarthQuake

The reason you see this problem is due to lack of bit-depth precision. What that means is the normal map has only so many possible color values it can use to represent the data that it needs to properly compensate for the smoothing, in this case the difference between the lowpoly and highpoly mesh normals is very subtle, so there aren't enough color values within that small range to represent the shape accurately. There are two typical ways that renderers deal with this:

1. Adding noise or dithering, this removes the artifact that you see, but it adds noise to the texture. This is what max does and is why you don't see the same problem
2. No dithering but then you get this sort of stair-stepping artifact, this is what Maya and Xnormal do.

Personally I prefer #1. If you can bake your normal map in a 16 or 32 bit per channel format, which gives you more bit precision or more potentional color values for your normal map, you can then convert to 8 bpc in photoshop which does a nice job of dithering as well. This is what I typically do when baking in xnormal, but I'm not aware of any way to bake in 16/32 bit with Maya.

seb3d

...but I'm not aware of any way to bake in 16/32 bit with Maya.

bake as EXR and you get a 32bit map!

crocoraffe

EarthQuake wrote: »

Personally I prefer #1. If you can bake your normal map in a 16 or 32 bit per channel format, which gives you more bit precision or more potentional color values for your normal map, you can then convert to 8 bpc in photoshop which does a nice job of dithering as well. This is what I typically do when baking in xnormal, but I'm not aware of any way to bake in 16/32 bit with Maya.

seb3d wrote: »

bake as EXR and you get a 32bit map!

i bake normal map in .EXR and it works perfectly, thanks for advice! :thumbup::thumbup: