Hard surface. Normal map issue after export into another programm....

Icedcg

Hi guys! I got problem with my normal map after exporting it from substance painter to another programm (Blender, marmoset toolbag 3 and even substance painter itself).

I have high-poly done with subdivision surface modifier (like turbosmooth in 3ds max), zero creased edges used, smooth shading applied to whole mesh. Exported to .obj using "write normal settings" so it stores all shading information. 

Here is high-poly:


Low-poly mesh has hard edges (splitted on UVs aswell). Exported to obj with triangulation, written normals, smooth edges.



Baking options in SP:



Baked normals looks good as for me:



Lowpoly with normal map applied looks like this:



The model looks very nice. You can see it even more clearly with this fill layer:



But then when I exported normal out of substance painter and applied on my lowpoly model it looks weird. I have tried different file formats, different normal map format (opengl or directx). I tried to import this model back to substance painter and applied it to my mesh and it still BAD. Here is some examples:

Substance painter 



Marmoset toolbag



Blender



I hope you can help me!
Thanks in advance! 

2bytes

The gradations in the normal map are the problem.  You will see pixel artifacts and some warping in the specular.  An additional fix to split UV and hard edges, is to add support edges  much like you would with support lopps in SubD modeling to the problem areas.  The the extra edges will reduce the length of the gradations.

Icedcg

So baked normal map isn't creating artifacts until its saved.... This is sadly because it means that i should add a LOT of geometry to fix all gradations on low poly.... Previosly I thought that gradations on normal map is opposite to gradations on model, so normal map fixes incorrect model shading. 

The only solution is to get rid off all gradations on lowpoly mesh, right?

throttlekitty

Just set your hard edges by angle for the low poly. While also cutting UV seams at those hard edges, give some space between these new shells. Shading-wise, it should look like your high poly in this case. It impossibly tight bevels on it- I would have thought that was your low poly if you didn't say so. You may want to think about relaxing those out. As they are now, you might have maybe one pixel in the normal map to represent that angle, and less than that when viewed from anything other than right in your face.

You'll never be able to overcome some gradient shading in the low poly 100% of the time. Check this thread out for some tips on dealing with banding artifacts.