Baking Perfect Normal Map

[Kelvin Loh]

Hi, recently I've been create an model in C4D and want to start texturing in SP, when I bake a normal map I seen some noticeable seams in some area. So I make a test, create a simple cube, uved, export low and high res mesh to SP.

And now have seams or jagged line in some area:





I thought this is uv problem, so I attach a uv screenshot here, is this a good uv for this cube model?



Thanks in advance.

[michael_11]

if you have separate smoothing groups, you need to split the UVs and move them apart

https://www.youtube.com/watch?v=ciXTyOOnBZQ

https://www.youtube.com/watch?v=m-6Yu-nTbUU

[Kelvin Loh]

Hi, thanks for sharing tutorials, I have watch it. I try to split padding the uv, but still can't get rid of this edge line when I re-bake normal in SP.

I also found this issue is cause by the uv border, so even I split the uv the edge is still exist.





Again, for smoothing group, because I using C4D, so there is no smoothing group function as in Max, It also do not have smoothing groups option in fbx export dialog. But I found a similar setting to smoothing model surface is the Phong tag on every objects.

I set angle to 180 degrees and uncheck "Use edge breaks", apply to all objects.





Is there anyway to smoothing the uv border to fix this edge line when I baking the normal map?

[michael_11]

not sure how normals work in C4D, but the cube, which you load into Painter, has one smoothing group - which is the reason for those gradients across the faces.
You will need to find a way how to control the normals for your geometry. Why not use Blender for this?

plus, for 90° angles, I am not surprised, that the bake doesn´t work for one smoothing group. The limit is probably something like 60°

[Kelvin Loh]

Now I have tried another workflow here, which is I add the supporting edges ( subd ) to model before uv, I found that a bit optimize than before without subd include in the uv, especially when the model is view at certain distance the normal seams will not too obviously exposed.

Here's a comparison with or without subd in uv:



When I heard using Blender, I start wondering is they have different computation of tangent space normal for each softwares? Unfortunately, I have no experience in Blender and never touch it before.

[crystalhann]

Now I have tried another workflow here, which is I add the supporting edges ( subd ) to model before uv, I found that a bit optimize than before without subd include in the uv, especially when the model is view at certain distance the normal seams will not too obviously exposed.

Here's a comparison with or without subd in uv:



This is a pretty interesting comparison. You have done great work to understand this issue. Thanks, it's really helpful for me as a beginner.

When I heard using Blender, I start wondering is they have different computation of tangent space normal for each softwares? Unfortunately, I have no experience in Blender and never touch it before.