ZBrushCentral

Question about workflow

ZBrush Usage Questions
#1

Hi there!
I am quite new to Zbrush and although I have a basic understanding of the modeling tools and can produce some decent sculpts, I am very confused when it comes to preparing my model for texturing, normal mapping and export. Perhaps some of you could answer some of my questions or point me to a relevant tutorial or something.

What I’m trying to do:

I have a sculpt that I made from a base mesh I made in Maya. The base mesh was never UV’d, I never had the intention of using it for anything else than the base of my sculpt. Now I know a common workflow(for games at least) is to make your low poly, UV it and then everything you do in Zbrush uses those UV’s and you dont have to worry about it. But I did not want to limit my sculpt to a predefined mesh. I wanted to freely sculpt it and then build a low poly based on the sculpt. The sculpt is now complete and is composed of many subtools. I notice the mesh flow of some of these subtools are really aweful( not sure if this will affect the normal map)and i don’t know how to fix it.

So my question is: What are my options for making a low poly and transfering the detail of my sculpt onto it?

I was thinking of making it in Maya but my Zbrush sculpt would be way too high to bring in as reference I think. I guess I could export every subtool individually but even then I think I’d run into problems. Plus once it’s made and UV’d I don’t even know how Zbrush would apply detail from one sculpt to a new low poly sculpt. Perhaps there’s some tools for what I’m trying to do and I’m panicking for no reason. Ideally I would like to combine all the subtools so I’m only dealing with one mesh but honestly my subtools are so high poly and unevenly distributed that I can’t imagine how Zbrush is gonna combine them.
Any help or suggestions would be appreciated,
thanks.

#2

Use SubTool Master to combine the low or medium resolutions of all your subtools into a single model. Then use retopology to create a new mesh with the edge flow that you’d like.

Once that’s done, append the new model to your original. Subdivide it to have enough polys to support the details that will be transferred. Then press Tool>SubTool>Project All. This will copy the details to the new mesh.

Now you’ll probably need to do some clean up on the projection, for with the ZProject brush will be really helpful. Then you can go to level 1, UV your mesh, and create your normal map.

#3

Ok thank you aurick, that helps to know I can do that.
One question though. You say I might have to clean up the new mesh. Does that mean i might lose some detail? If so, for next time, would you recommend doing this retopo earlier in the sculpt before it gets too detailed?

#4

I like to use maya to retopo. I just us zspheres at the begining and worry about the uv’s when I’m done. You just need to export a mesh just high res enough to keep your basic form. I export out each of my sub tools that way and sometimes have to break up a subtool if it’s still to high res, but not usually. After you retopo the high res mesh you have a high res bad topo mesh with all the detail you want and a low res good topo mesh with uv’s done. Now in zbrush you make the good topo mesh a subtool of the bad topo mesh and crease then subdivide the new good topo mesh until it has a similar # of poly’s as the high res bad topo mesh. On the good topo mesh at its highest subdivision you “store morph target”. Then while both subtools are showing and you have the good topo mesh selected, do a “project all” found at the bottom of your sub tool pallete. Usually from here you’ll have some wonky areas on the good topo mesh, but since you “stored the morph target” you can now use the morph brush to smooth out the bad areas and the zproject brush to reproject in the trouble areas. It’s not magic, it’ll take some back and forth with this process to get it right. Once you’re done with that you can now extract all the high res data from the bad topo mesh to make your Normal Map using zbrush’s zmapper.

There are some variations to this process depending on what your sculpt consists of, but in general terms this should work. :slight_smile:

#5

Thanks for the tips.
I tried projecting my high detail mesh onto my new good topo mesh but 2 seconds after I press the projectAll button Zbrush crashes due to Ram issues.
I have 4Gb of Ram. My original combined tool is about 6 mill poly and I divide my new good topo mesh to about the same maybe more.
Perhaps I can project pieces of my orginal one at a time? Or will this create seems?

#6

It’s hard to give the best suggestion without seeing pics of the work. You can do a project all in sections, if there are seems then just make sure that your sections overlap to make sure there are not any seems. Ex. If its a leg, hide everything down to just above the knee, project that, then hide everything except for the thigh just below the knee, then project that. I hope that made sense.:smiley:

#7

Yes I know exactly what you mean, I just wasn’t sure if that were possible.
Fortunately I solved the problem. My memory settings kept resetting and were set very low. I cranked it up and it’s fine now.
I’m having some issues with verts exploding but it seems that’s a comon problem and can be fixed by hiding some problem geo such as inside mouth and sockets.