Artifacts on UV seams related to Height

[Christos26594625g3fn]

Hello everyone! I am fairly new to 3D modelling and texturing. I have repeatedly encountered an issue in Substance Painter that I cannot really find a solution online for. I often get artifacts / black lines around the UV seams. After trying various tweaks to see if they would go away, I found out that they are caused and affected by Height. For example, if I disable 'Height' on my material, they disappear. Similarly, if I set the Height Ranger slider to 0, they disappear. Height Position is also similar - If the slider is set to 0 or 1, the artifacts disappear. If it's set anywhere in between, they appear. I have attached a bunch of images with examples of the issue and how it disappears when I play around with Height settings, as well as an image of the UV's.

For the record, I use Maya LT for modelling. Can anyone help me out please? Is it something that I can fix in Substance, or is it that I am doing something wrong in Maya while UV'ing?

Thanks a lot for the replies! 😃

[Cyril Dellenbach]

Hello @Christos26594625g3fn,

Thanks for all the visuals, it always help to understand the issue.

A seam on your UV map cuts the flow of your texture. Therefore between one border of the seam and the other, the values will change brutaly. Depending on your texture, this change can be apparent, and that's why we always try to hide the seams. 

For your case, I would try to project the texture with the Tri-Planar projection instead of the classic UV Projection. it should erase these black lines.

Let me know if it worked and have fun with the Adobe Substance suite !

[Christos26594625g3fn]

Hello Cyril,

Thank you so much for the prompt response, very appreciated! I have indeed tried switching to Tri-planar projection, but it does not really fix the issue. It just moves the artifacts around, sort of - some of the artifacts do get removed, others remain, while some seams that do not have artifacts with UV projection do have artifacts with tri-planar projection. I have attached two more photos that show the artifacts with tri-planar projection.

For the record, the way I've been dealing with this issue all this time is using the clone tool in a passthrough layer over the seams to make them disappear. It's a neat trick I've seen many recommend online. However, I feel like it's not really a fix to the issue but rather a coverup, if that makes sense.

[Cyril Dellenbach]

Hi again @Christos26594625g3fn,

Would you agree to share your models (low and high poly), so I can dig deeper into the problem ? If you do not wish to share your models on this thread, you can send it to me directly to: cdellenbach@adobe.com 

And I agree, it's great that the clone tool helps you with the issue, but it would be better without issue.

Best regards,

[Christos26594625g3fn]

Hello agian Cyril,

Thank you for your help. I apologize for the delay in my response.

I certainly do not mind! I have attached an .fbx export. Note that I haven't used a high poly to low poly. It's a single 3D model with a relatively low poly count on which I have applied the textures directly.

Thanks once more for your help, it is very highly appreciated!

[Cyril Dellenbach · Accepted solution]

Hi again @Christos26594625g3fn and thank you for your patience.

I've checked your mesh and the issue is related to the sharp smoothing groups the 3D model has. When you add a sharp edge with blender (blue line), it will strongly switch how the model reflects light and this can logicaly affect the normal map, which is affected by the height painting in Substance 3D painter. Therefore, I would advise you to avoid using smoothing groups for your LowPoly.

But obviously, the goal is to keep these sharp edges without the artifacts. For this purpose, keep the horseshoe with smoothing groups and use it as a high poly to bake your model.

This way, you should have hard edges and no artifacts. 

With that being said, my previous answer about UV seams still applies, so make sure to hide the seams or to use a Tri-Planar projection.

I hope this will be helpful and have a nice day.

[Christos26594625g3fn]

Hello once more Cyril, and thank you so much for the solution! I hope this thread might help more newbies like me in the future, too! 😃

[PipoodeKloon]

Got the same issue on my models.
Found this "way around/fix" for this problem and it's prettty okay-ish =>
https://www.youtube.com/watch?v=lnTHVGI90i4