Hi
I need to decimate an obj mesh with texture to under 5000 points. Unfirtunately, once Decimated the texture doesnt apply as before.
How do i decimate and keep the texture?
Hi Paul!
Any time you change your topology, you’re going to break the UVs that make applied texture maps display properly. If textures are involved, you generally want to avoid decimation as it creates problematic geometry for any mesh where topology is a concern. You need to first convert your applied texture to polypaint at high resolution, create a new multi-subdivision level version of your mesh with a low poly base that can be used in applications that cant work comfortably with Zbrush level polycounts, project the color and sculpting detail from the original mesh, and convert the polypaint back into a texture for the new mesh, with new UVs.
Forgive me for a bit of CopyPasta here, but it’s a common source of confusion:
So the first thing you need to do is to convert your applied texture to polypaint in your source mesh. Do this at high enough subdivision level that the mesh can hold the vertex color data–the fewer points, the less detail.
Then create a lower poly version of your model, and give it multiple subdivision levels. Duplicate your source subtool so the original is preserved. ZRemesh (or otherwise retopologize) the duplicate to have a lower polycount with well distributed polygons. You will lose detail doing this, but you’ll get it back.
Subdivide your duplicate mesh (Tool > Geometry> Divide) up to a density sufficient to hold the surface detail, as well as any polypaint. Follow the instructions on this page, and project the detail (color and sculpting) onto the newly subdivided model. You should now have a version of your model with all the detail intact, except now with multiple subdivision levels and a low poly base level.
From here, you can create UVs for your mesh. Switch to the lowest SubD level and follow the directions on creating UVs, either with UV Master, or one of ZB’s quick tile mapping options, or with any other tool you prefer.
With a newly UV’d model, you can now convert your polypaint to an image texture. This is how a model can be exported at low poly, and still retain the polypaint color information which would otherwise lose detail as you reduce polygons.
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Have you tried the Zplugin: Decimation Master: Keep UVs option? A quick test with the Earthquake model showed the plugin doing a great job of maintaining the UV layout even when dropped down to under 2k points.
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