Blurred Normal Map in cube shaped objects

arkaneXXI

I have this cube:


This is the UV:


When I bake the normal map in Substance Painter, I get this:


This just happens when I bake the normal map in cube shaped objects. I don't have this issue with more complex objects.

Anyway, the result on the model doesn't look so bad:

But I had to increase the Max/Min Frontal/Rear distance on the Baking options from 0,01 to 0,02. Otherwise, this is the result:


Somebody knows why this is happening or should I ignore these issues?

Ghogiel

There is a lot of missing info.

I suspect you either mean the diffusion at the border padding or more likely gradients in the normal that are correcting the surface normals of the baked cube to match whatever the mystery object you are baking from. Both are expected behaviors, the first is because you set diffusion on in the bake settings, the later is the low poly cube is probably smooth shaded and the normal map you are creating is trying to correct the surface shading of that cube to better match the surface of what ever mystery cube it is you are baking from.

arkaneXXI

Ghogiel said:

There is a lot of missing info.

I suspect you either mean the diffusion at the border padding or more likely gradients in the normal that are correcting the surface normals of the baked cube to match whatever the mystery object you are baking from. Both are expected behaviors, the first is because you set diffusion on in the bake settings, the later is the low poly cube is probably smooth shaded and the normal map you are creating is trying to correct the surface shading of that cube to better match the surface of what ever mystery cube it is you are baking from.

Thanks for replying. This is the result with the "Apply Diffuse" option unchecked.


About the "smooth shaded", are  you talking about the "Smoothing Groups"? The model has a single smoothing group because there aren't hard edges, since they are chamfered. Should I use different smoothing groups and separate them in different UV isles/clusters even if there aren't hard edges?

gnoop

Modern approach is "face weighted normals" or saying it simply you just need to rotate vertex notmals to be perfectly perpendicular to the cube sides

Shrike

Result looks fine to me?   
Substance also does easily the worst bakes of all non-3d modelling software Ive seen so far

arkaneXXI

gnoop said:

Modern approach is "face weighted normals" or saying it simply you just need to rotate vertex notmals to be perfectly perpendicular to the cube sides

Thanks a lot for your reply. Sorry for my ignorance, but I didn't know about those "face weighted normals". I searched more information about this topic and I found this wonderful video:
https://www.youtube.com/watch?v=G-K7WT9IIok

That explains everything perfectly and how to solve the problem.

arkaneXXI

Shrike said:

Result looks fine to me?   
Substance also does easily the worst bakes of all non-3d modelling software Ive seen so far

Yes, one month ago I realized that (sometimes) everything looks perfect on Substance, but when you import the textures to another software, you start to notice the problems.

It seems the problem isn't the cube, but the chamfered/beveled edges. As gnoop said, this can be solved with the "Face Weighted Normals":
http://wiki.polycount.com/wiki/Face_weighted_normals

Everything is explained on the video I have posted. I'll try that tomorrow and post the results.

gnoop

Keep in mind you don't have to make every edge beveled.  You could bake perfectly  beveled impression on a hard/split edge by means of normal map only  using  rounded corner shader in many soft. Blender, Modo, Max with Arnold ( with some extra job)  without any hi res mesh.    

 

Making bevels is a waste of geometry along UV splits . One smooth group or not a game engine would split mesh along UV islands anyway doubling vertex count.

  In a word you should make those bevels inside UV islands and keep hard edges along UV islands borders in case of something more complex than just a box.

 

Noren

And just to drive this point home: There is nothing wrong with your initial bake. The normal map does exactly what it's supposed to do.

Weighted vertex normals are more elegant in a way, can probably be compressed better and will show less errors with discrepancies between baker and real time rendering solution, but there is nothing wrong with your initial outcome. (Also you need to be careful to not lose weighted vertex normals).

arkaneXXI

gnoop said:

Keep in mind you don't have to make every edge beveled.  You could bake perfectly  beveled impression on a hard/split edge by means of normal map only  using  rounded corner shader in many soft. Blender, Modo, Max with Arnold ( with some extra job)  without any hi res mesh.    

 

Making bevels is a waste of geometry along UV splits . One smooth group or not a game engine would split mesh along UV islands anyway doubling vertex count.

  In a word you should make those bevels inside UV islands and keep hard edges along UV islands borders in case of something more complex than just a box.

 

Actually, the box was just for experiment. This is the model I'm doing:


I did the cube test because I had a horrible shading on the sidepods (the things on the sides), but that issue isn't visible with the normal map. As you can see, the sidepods are the only piece beveled.

I didn't understand the last thing about "make those bevels inside UV islands" (maybe because my English isn't so good).

arkaneXXI

Noren said:

And just to drive this point home: There is nothing wrong with your initial bake. The normal map does exactly what it's supposed to do.

Weighted vertex normals are more elegant in a way, can probably be compressed better and will show less errors with discrepancies between baker and real time rendering solution, but there is nothing wrong with your initial outcome. (Also you need to be careful to not lose weighted vertex normals).

Yeah, I can leave the model like that, but I'm picky with details : P

I prefer everything be perfect to avoid problems in the future.