Need help in baking related problem

rafiii · Mar 21 2025

I’m experiencing a baking artifact and have tried various solutions but haven’t been able to pinpoint the cause. If anyone can help me identify the issue, I’d really appreciate it!
Low Poly mesh:
https://www.dropbox.com/scl/fi/cxrgs8x8hy2ns0bynweqy/Fire_hydrant_low_poly.obj?rlkey=wz3wg55mr1zqxmotuyjackmzg&st=ce91bt65&dl=0

Image: https://us.v-cdn.net/5021068/uploads/editor/nr/8o0bsda5au25.png

Image: https://us.v-cdn.net/5021068/uploads/editor/hg/remlt6f2s7ek.png

Fabi_G · Mar 21 2025

To solve the issue presented in the first image, I would match the lowpoly curvature closer to the highpoly. Check out this valuable thread on the topic: Understanding averaged normals and ray projection/Who put waviness in my normal map?

The exact issue shown in the second image is hard to determine without more information. Easiest way would be to share meshes (parts showing the issue), so others here can reproduce it.

rafiii · Mar 22 2025

Fabi_G said:

To solve the issue presented in the first image, I would match the lowpoly curvature closer to the highpoly. Check out this valuable thread on the topic: Understanding averaged normals and ray projection/Who put waviness in my normal map?

The exact issue shown in the second image is hard to determine without more information. Easiest way would be to share meshes (parts showing the issue), so others here can reproduce it.

Thanks a lot for your help! I really appreciate it. As I was new to this, I didn't know that. I have updated the post with the mesh link and I will keep that in mind next time.

Fabi_G · Mar 22 2025

Hm, when I dropped the lowpoly mesh into Blender to inspect the UVs unfortunately look broken:

Image: https://us.v-cdn.net/5021068/uploads/editor/0w/h21cbd3l9hkb.png

Looking at the lowpoly, I suggest:

Reduce amount of support loops, use as much as needed to get a good mesh shading. Put the saved geometry into the curvature of rounded/ cylindrical parts. The impact on the assets silhouette is greater.
To keep an even density and closer match the highpoly, you can fan edges going toward wider curves.
Straighten UV islands where it make sense, for example strips from tube-like shapes. With a subject like this, UVs shell could be split up into strips and caps. When baking unique normal maps, split UVs at hard edges to avoid artifacts. The issue in your second screenshot could stem from the UVs not being split along hard edges.

Attached you find a modified lowpoly, illustrating above points as well as a 1k normal map (OpenGl).

Edit: If you wanted to optimize polycount more, could simplify the top cap, removing the insets from the low poly, having that detail purely in the normal map.

rafiii · Mar 23 2025

Fabi_G said:

Hm, when I dropped the lowpoly mesh into Blender to inspect the UVs unfortunately look broken:

Looking at the lowpoly, I suggest:
Reduce amount of support loops, use as much as needed to get a good mesh shading. Put the saved geometry into the curvature of rounded/ cylindrical parts. The impact on the assets silhouette is greater.
To keep an even density and closer match the highpoly, you can fan edges going toward wider curves.
Straighten UV islands where it make sense, for example strips from tube-like shapes. With a subject like this, UVs shell could be split up into strips and caps. When baking unique normal maps, split UVs at hard edges to avoid artifacts. The issue in your second screenshot could stem from the UVs not being split along hard edges.

Attached you find a modified lowpoly, illustrating above points as well as a 1k normal map (OpenGl).

Edit: If you wanted to optimize polycount more, could simplify the top cap, removing the insets from the low poly, having that detail purely in the normal map.

1. Hm as for UV. That also happened to me. I uv the mesh in rizom-uv to check it out. Whenever I imported the mesh the UV was broken but when I re-imported the mesh the UV was as good as it was in rizom-uv. I don't know what the problem is.
2. About using less support loops. I wanted to have smooth areas in those areas, so I kind of beveled those parts to have smooth areas. My question regarding that is rather than doing so can I only select that edge loop and soften the edge loop instead? And if so how should I cut the UV when I won't have any hard edges in that area?
3 . Actually for the top cap when I reduced unnecessary loops and edges the silhouettes weren't matching with the high poly so later I just sub-divided the low poly and converted it to low poly and reduced as many polygons as I could to keep the silhouettes.
Regardless of this your help is very much appreciated. I am so new at it so I don't know much stuff and trying to figure out my own. Thanks again for your help.

Fabi_G · Mar 23 2025

On UV issue - well that's curious and something you'd want to resolve. I recommend checking the asset in engine (assuming it's a game asset), alternatively could import into a fresh file.

Regarding supporting loops/ bevels: I think once the mesh shades nicely, adding more support loops will do little and mainly increase the polycount. When an edge is shaded smooth splitting the UVs is not neccessary. Wiki contains more info on baking and best make some side by side tests by yourself.

Best check assets in engine/ at intended distance in context (for example next to some benchmark assets). I think working on assets in isolation, one can loose sight of the final result, for example obsessing over edges/ details one never gets close to or are never seen.

rafiii · Mar 24 2025

Fabi_G said:

On UV issue - well that's curious and something you'd want to resolve. I recommend checking the asset in engine (assuming it's a game asset), alternatively could import into a fresh file.

Regarding supporting loops/ bevels: I think once the mesh shades nicely, adding more support loops will do little and mainly increase the polycount. When an edge is shaded smooth splitting the UVs is not neccessary. Wiki contains more info on baking and best make some side by side tests by yourself.

Best check assets in engine/ at intended distance in context (for example next to some benchmark assets). I think working on assets in isolation, one can loose sight of the final result, for example obsessing over edges/ details one never gets close to or are never seen.

Ah, I see. Those are some valuable tips I will keep that in mind.

Need help in baking related problem

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