How From - high Poly to low Poly in zBrush

werkvoll

I'm a student at the university in salzburg and i study 3D-Animations. A Friend and i currently making a video game. For the game I did a Model in ZBrush. The UVs came from Maya.

My question is, whats the best way to get a low poly model out of this. With decimition master i lose my uvs. And i'm not shure if i could keep my maps without uvs.

I count on some master tips, from the great masters of this forum .

At present i looks like this (I just started painting, the player will only see the model from the top):

WarrenM

Did you toggle on "Keep UVs" in Decimation Master?

Oniram

you would either have to retopoligze the model either within zbrush, or any other software: 3dcoat, maya may have some scripts out there, etc. once you have rebuilt your mesh you will then need to give that its own UVs, to which you can project the normals, diffuse, etc from that zbrush model.

decimating or breaking down the model isnt just a bad idea because you lose your UVs, but it doesnt know what your mesh looks like, so you will not ever have proper edge flow.

cryrid

Avoid Decimation Master. It's meant to preserve surface detail of sculpts while reducing their weight, not produce low-poly meshes that are suitable for things like games.

Take Oniram's advice and manually retopologize it. The final low mesh is what should have UVs (they rarely make a difference on the sculpt beyond a larger filesize).

Edit: I suppose I should restate things to prevent confusion. Avoid DM for this sort of thing. It has uses, direct retopology is not one of them.

werkvoll

Thanks guys. I'll try, and repost.

meshiah

echoing,
standard procedure for z brush and game modeling. deck your hi poly mesh out, don't waste time on uv's/wires or anything you dont need to, just pure design.
when your done you'll see where your low poly mmodel needs the polygons to either support detail or bend for animation.

although for me and this procedure, decimation master is HUGE! you can group,decimate, and export, with like 5 clicks now, so you can bring in any supporting rezolutiuons you need to quickly retopo over any kind of problem.

oniram is just saying dont use decimation for your final mesh wire frame, but by all means use the shit out of the feature!

werkvoll

Thanks for the answers, but:
@meshiah, could you give me an example how you would do "deck your hi poly mesh out, don't waste time on uv's/wires or anything you dont need to, just pure design."

Do you mean i should make my high poly mesh in zbrush, and them rebuild it as a low poly version in maya. But how could i get my maps i painted in Zbrush on this new model ? oe do i understand you totally wrong ?

cryrid

Do you mean i should make my high poly mesh in zbrush, and them rebuild it as a low poly version in maya. But how could i get my maps i painted in Zbrush on this new model ?

ZBrush's polypaint uses the vertex colors, so painting is independent of UVs and texture maps. This lets you paint first, then worry about UVs later. Two options include:

1. Xnormal. It can read the polypaint data from the highpoly sculpt and bake it to a texture map for the low poly. This is the quicker method.
[ame="http://www.youtube.com/watch?v=dvNOCojBRoE"]xnormal Zbrush Polypaint - YouTube[/ame]

2. Assign the sculpt some quick and dirty UVs after it is painted. You could either use UV Master, or PUVTiles (Tools >> UV Map >> PUVTiles). Then convert the polypaint to a texture (TextureMap >> New From Polypaint). To export it, click the 'Clone Txtr' button to send it over to the texture pallete, where it can then be exported. Most baking programs should be able to read the texture information on the sculpt and bake it to a new texture that matches the lowpoly's UVs.

http://eat3d.com/free/zbrush_xnormal

werkvoll

That should work for me. Thanks a lot for your time .