help Ambient Occlusion when UVs overlap.

[kyanokong]

I have a question about ambient occlusion when UVs overlap.
When I checked the Ambient Occlusion output results of a model with overlapping UVs and a model with no overlap, there was a difference.

The version is 2024.17.

This result can be a little inconvenient in certain situations.

Is there a setting that would give this output the same result?

[Elemeno]

11 hours ago, kyanokong said:

I have a question about ambient occlusion when UVs overlap.
When I checked the Ambient Occlusion output results of a model with overlapping UVs and a model with no overlap, there was a difference.

The version is 2024.17.

This result can be a little inconvenient in certain situations.

Is there a setting that would give this output the same result?

3dcoat has had trouble baking light or AO or a mirrored model... quick fix , half your model, bake the light /AO export the textures and then bring in your actual mesh and place those textures in and it will work fine , you can also not bake using render rooms lighting etc and it will generate proper lights and AO but will be default top down 

[Elemeno]

4 minutes ago, Elemeno said:

its just light baking onto a mesh thats using mirror uvs .. i dont think any texturing or baking software does it too so its not just a 3dcoat thing but i will check for you

yea painter and marmoset give same results so its not just 3dcoat its the uvs trying to baking multiple shadows on a mirrored uv

[kyanokong]

thank you for your reply.
I'll try to respond the way you said.
I hope this improves.

[Oleg Shapov]

17 hours ago, Elemeno said:

3dcoat has had trouble baking light or AO or a mirrored model

Can I ask you for more details about this problem?

[Elemeno]

2 hours ago, Oleg Shapov said:

Can I ask you for more details about this problem?

its just light baking onto a mesh thats using mirror uvs .. i dont think any texturing or baking software does it too so its not just a 3dcoat thing but i will check for you

[Carlosan]

Source...

OVERLAPPED RENDERING
The first problem is straight forward: if a pixel of a texture is used twice by a polygon’s UV coordinates, your baking process will write to that pixel twice, overwriting previous information. This isn’t always a problem, but can result in weird facetted bakes that are completely unuseable. Since you should always strive to make the most out of your UV space, uniquely unwrapping the otherwise overlapping parts is not a solution for this.

The baking process is clearly the only problem here.

The solution is to offset your overlapping parts. You move one or more of the overlapping parts (so there’s only one polygon occupying the UV space) exactly 1 UV unit aside. This makes sure there is no more overwriting. Out of bounds texture coordinates are wrapped back during texture lookups, but not during rendering to texture, fixing our problem.

NON-SYMMETRICAL AO SHARING
Symmetrical objects can easily share AO texturespace, al you have to do is mirror their UV coordinates. Problems arise when the AO baked onto the texture, is not correct for each side. Imagine a car bumper, where each half shares the same texturespace. Now if there is some sort of detail in front of only one half of the bumper, you might end up with a black spot on the other half of your texture, even though there is no occluding geometry there.

In such a simple case, it’s enough to only bake the half without occluding geometry and trade off some accuracy in your AO maps. More complex problems arise when you have object that are really different in terms of occlusion, use the same space. Depending on how wrong the bake is, you might even have to completely overpaint small parts of you baked AO. Just try to keep it really generic in terms of occlusion, just some simple shading that works for all geometry using the texturespace.

another solution...