Daemoria's avatar
Zbrush uses catmul-clark subdivision, so there is an even distribution of polygons, provided you stay away from 5+sided ngons on your lowers subdivision level.

Mesh optimization would only be calculated after you are done sculpting, not at run-time, because the way most (if not all) optimization algorithms work, it'll destroy the underlying topology in such ways as to make sculpting impossible... And it has a great tool for this, called Decimation Master.
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AStepIntoOblivion's avatar
No no. LOL. I needed around 3 million vertices for the displacement maps to translate into geometry correctly (for each subgroup I made, which makes the total amount of polies of the high res model to around 30 million). Otherwise too few polies will result in a model that has squarish edges when the displacement map is translated into actual surface deformation of the geometry.

And again that's for the HIGH poly. The source of the normal maps/displacement maps. There is also a feature called equalize distribution [of edgeloops] or something, but it destroys uv maps, so i was careful to add enough loops in the lowpoly itself so when i subdivide it inside zbrush, the number of verts is distributed equally resulting in a smoother geometry when displaced.

And no, it does not actually provide an even distribution of polys. Subdivision density will depend largely on how many edgeloops existed in the base mesh in the first place. Which is why its good practice to add more edgeloops to the lowpoly beforehand with the same topology and uv's as your real lowpoly but with a higher amount of edgeloops so that when subdivided the density is more or less equal all throughout the model - the highpoly gun featured in wireframe in the pic above is an intermediate lowpoly mesh like I described.

Decimation master is more or less only useful for non game-mesh models (i.e. you are not decimating from 3 million to 5k). It leaves you with a mesh composed entirely of triangles and more often than not distorts your uv's as well. It's good tho for exporting high res models into another 3d app for a proper render.

The actual model shown here is only 2094 polys (around 2.3k vertices), but with normal maps applied from the high poly model, and it's perfectly game-ready.
Torquinox's avatar
And my point, for what it's worth, is that Z-Brush seems to encourage the creation of enormous models, as indicated by the ad for the Decimation Master, where they're showing part of a character model that already has over 7 million verts. That's a lot of geometry. Your low-res model is still not exactly tiny, but *is* efficient compared to what I've seen out of Z-brush.