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Zbrush > Maya. Polygon artifacts showing when soften edges

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See the pictures above.

The following artifacts show up after exporting from Zbrush (Decimation master), exported as FBX. Even after baked normals applied. Any idea what might cause this? I've tried decimating at different values, changing settings on the normal or baker, cleanup mesh Maya.

Thank you very much for taking the time to have a look.

  1. View in Maya (With and without Wireframe)
  2. View in Zbrush after the decimation of the same area.


  • Neox
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    Neox high dynamic range

    thats to be expected. where do you bake your normalmaps? maya has its own tangentspace, so unless you final output is in a maya tangentspace engine, make sure to actually check the bakes inside your engine. NOT maya

    and you should get rid of such super narrow triangles. will be hard to give them the proper uv space and compensate their shading with a normalmap

  • gnoop
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    gnoop polycounter

    I think the whole idea of using Zbrush decimated mesh as in game model is not ok yet. Whatever Unreal5 is promising. I see the appeal but IMO not only those tiny triangles everywhere Neox mentioned but neither proper/clever sharp edges vs smooth surfaces placement for good lods switch without suddenly popping different shading in a next lod is there yet.

    At the same time nothing prevents you from fixing those things in 3d package after the export. Those shading artifact is a matter of just one vertex normal rotating to proper angle. It would never be 100% perfect but you could easily find the normal angle where such a gradient shading would go to less apparent place. Also you could always have a sharp/split edge there and split uv in same place . Rotating/switching edge direction manually also helps.

    Hard/split edges still may create some issues in real time rendering if your target game engine is mostly using forwarded technique with not hi res enough cascade shadows and also with not that advanced SSAO techniques . They often reveal the hard edges whatever smooth beveling you create in normal maps . So on a mobile game it could be an issue for sure . But this rock subject is all of hard edges visually so could be still ok.

  • Benjammin
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    Benjammin polycounter lvl 5

    I mean, there's nothing wrong with it; Decimation master is doing what you asked it to do :) Sure, its a messy result, but the tool isn't called 'make low-poly mesh I can bake to'.

    As gnoop says, its super easy to clean this up. You can use masks when using decimation master, but in this case that's a more involved process than manually fixing it.

  • JulezKaidy

    Hey, thanks for letting me know!

    I do regularly check them in Engine (Unreal). The problem persists there AND in Maya. However, you hardly see the artifact in Marmoset (where I bake the normals. the Same goes for Painter when I gave it a go there). only in Maya and Unreal does it really get apparent. Also, keep in mind that there's no normal map applied in the example image, but that the artifact does shine through the normal map in the engine, etc.

    Good call on the topology. I will definitely clean that up and hopefully tackle the problem from there. Any tips on how to quickly/easily take care of this? or is it just hand work?

  • JulezKaidy

    Really well-written explanation with tons of tips. Thank you so much!

    Fully understand and will have a look/keep these things in mind for future assets. Also thank you for your thoughts @Benjammin . Will dive into it right now and try to get it solved in a few different ways to see what works and what doesn't :)

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