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ZB 4 Normal map help

ZBrush Usage Questions
#1

Hello!

I can’t really find this info, and sorry if it’s in wrong section, wasn’t sure where to open this thread.

Anyhow, lets say i sculpted nice high poly …Human. Now i made low poly model (retopo in topogun for example), uv mapepd it in maya, and then imported it into zb again.

So now i have two different subtools, so to speak.
Now, how to i project normal map, from that high poly model, to this new, modified and imported, low poly model? Since they would be two separate subtools, i have no idea how to aproach this, and i would prefer it to do in ZB and not in xormal or such (exporting several milions polys to obj or so is probably not such a good idea anyhow). So i’d prefer to do it in ZB…but how?

Cheers,
Zocky

#2

You would have to subdivide the new model enough to have sufficient geometry for the detail, and then use the ProjectAll button (Subtool sub palette) to transfer the sculpted detail onto the new model and then bake like normal. This transfer isn’t always perfect, so you might want to save a morph target first so that you can ‘paint out’ any projection errors.

Personally, I still prefer using a program like xnormal as it gives more control (cages, mesh normals, etc), doesn’t require the lowpoly to act as a subdivision level, has a better shot at providing the right tangent basis (at least one that is synced to its model viewer by default), and can still read zbrush’s polypaint information on imported meshes. It can handle large models easily enough, and zbrush’s Decimation Master does a wonderful job reducing a mesh’s weight while still preserving the kind of surface detail that a bake would want.

#3

Tnx for reply.

I do wonder then, do you export to obj in that case? And if so, what is the polycount where you still have relativly normal performance (for example, to import one milion tris in maya with obj is almost impossible).

Also, is there no way to directly transfer normal map from one subtool to another?

#4

Yup, export a mesh with polypaint as an obj, and it should all be readable.

Regarding performance, I think that might be another plus with xnormal; because it’s not displaying the models in the same way as a program like Maya would, larger files shouldn’t be too much of an issue (loading them into the built-in model viewer can be a different story). I wouldn’t know an exact number as your mileage may very, but I’ve used it with meshes over a million tris and it worked fine even though my laptop is from 2007. And now with Decimation Master, it’s even easier to get the same results with a fraction of the triangle count.

But as far as doing the bake in zbrush, I don’t know of any way that would let you bake a normal map from different meshes. Zmapper might have allowed it, but that’s been long gone.

#5

Tnx for the info!

I tried to import from model from zbrush into xnormal, it had around 4.5 milion triangles, and took only like 3,4 mins to render normal map, wich is very good i’d say. It went even faster next time, even though i change low poly mesh. I guess high poly was “cached”.

Tnx, i think i will use xnormal!