ZBrushCentral

Working with subtools?

ZBrush Usage Questions
#1

I seem to have a lot of problems trying to use things as subtools.

Is it possible for something to both be attached to the main mesh and a subtool? For example I really don’t want to mess my hands up as I’ve put in a huge amount of effort, but of course I need everything to be one mesh when I’m done at the very least and in order to make things look right they have to be attached. Is there some way for this I’m missing or are subtools as nearly useless as they are seeming to be for me so far?

Is there any way to keep that hand’s geometry when merging it to the rest of the thing? I spent forever getting it just right. As it is it seems all I do is retopology and doing it again on that intricate work is extremely unappealing…

#2

SubTools are separate meshes. This allows each one to be taken to your system’s max polygon count. Thus, a model can be 20 or 30 million polygons even though your system bogs down at 5 or 6 million.

Why are you trying to combine the SubTools again later? Why not work like this:


  1. Create your base mode and UV it
  2. Split your model into SubTools
  3. For each SubTool, store a morph target
  4. Divide, sculpt and detail as you wish
  5. For each SubTool, go to level 1 and switch to the stored morph target
  6. Create a displacement or normal map for each SubTool
  7. Apply those maps to the original base in your rendering engine

#3

If I had say ten subtools wouldn’t that give me ten different normal maps?

The basic problem I have is that it seems impossible to work on say a hand on a full body mesh without having it be separate.

I already have all the pieces that I want for a full body but now I can’t seem to join them together without great pain. Maybe this is not something that works out well in zbrush but it’s my first attempt to do anything and I did not know any better…now I’ve spent a great deal of time and have nothing to show if I can’t get this working somehow.

I’ve joined all the subtools together, but now of course the geometry is way too high for a game engine. I (apparently foolishly) did a retopology of each of the pieces that’s good already. I could possibly assemble all this outside zbrush but it would be a ton of work.

Is there just some way to project parts of some of my subtools onto the main big mesh somehow?

Failing that is there just some way to focus on just the hand as if it were a subtool? I honestly don’t need to have 20 million polygons on just the hand, the issue is I can’t get any sort of progress done because I just can’t keep it focued on a part like the hand when there’s a bigger mesh involved.

I’ve tried setting pivot points while I am trying to retopologize, but it does not seem to do anything that makes sense. The zspheres seem to separate from the mesh and go crazy and if I draw on the mesh then revolve the pivot point I get geometry in the middle of space. It seems like there absolutely must be at least me something that can let me focus on the hand (or elbow or whatever) and spin around it and retopologize. Otherwise it’s just not practical to try to do it that way.

Also, even when I try to just join subtools in the subtool master at the lowest level I get these crazily high polygon counts. I’ll have say 6k worth of geometry and put it together and I wind up with something like 200k polygons. Is this normal? If I could get the subtool master to work in a reasonable manner then I could skip doing the hands and just join them on that way, but it doesn’t seem to be able to do what I want it to do. Am I just doing something wrong?

Thanks for bearing with me, I know it’s a pain to read through all this and I appreciate your help.

#4

Anyone?

Is there at least some way to focus on one part of a mesh so that I can rotate aound it? Or around just the visible parts of the mesh.

There just seems to be no way to do this and without at least that I have to think zbrush is pretty worthless at least to me. I don’t want to make just pictures and I don’t really need it if all the use I can get out of it is fine detailing for normal maps.

#5

Look at my steps again. You UV the model before you split it into SubTools. You can control however many normal maps you want.

Of course, when you go to actually create the normal maps you will end up with one for each SubTool. But if you laid the UV’s out before splitting the model, then you can combine these normal maps in Photoshop after you’re done.

Of course, keep in mind that if your 10 SubTools total 30 million polygons between them then you’ll need three 4096x4096 maps or about nine 2048x2048 maps to hold all that detail.

#6

I know I can do it that way, bit I didn’t do it that way and I don’t want to throw out 6 weeks of work. That’s also not the way I want to work if I can avoid it, because it is very cumbersome.

Can you answer any of my other questions? Especially the last one? I am sure it must be possible to center on one area of a model and rotate around it but I just can’t seem to figure out how.

#7

Ok, I figured out finally that the polygroups will do the last part I asked about. Sorry if I am being obtuse, there’s just so much to figure out.

If anyone else has any ideas on the rest I’d appreciate it, but I am guessing I am just out of luck in those regards.

EDIT: damn! That works for the detailing, but not for retopology. The issue is that I have merged everything together but the geometry count went to a ridiculous level and there are overlapping areas I need to fix.

Retopologizing the hand parts when the rotation is based on the center of character is an enormous pain that might take days of work. If anyone has suggestions (besides not to do what I have done) then they’d be appreciated.

Starting over is just not an option. If I have to do that at this point I am ditching zbrush completely, and probably the whole project. I’ve already spent too much time as it is.

#8

Under transform, click the “Local” button, this will ensure that you rotate around the last point on the model that you were editing. This is very handy for retopo.

#9

Thank you so much. That will help me immensely in the future and save me a lot of frustration.