I just recently started using zbrush and I watched all the tutorials on pixilogics website. They couldn't include everything that I needed to know to answer some of my questions, but I was wondering if you can add more geometry to work with such as eyes or hair if you didn't make it in Maya/3dsmax and export it. Can you work with layers and add more geometry in zbrush? Or must you only model it it then export it? If you like here is a link to the model I did:
I'm going to just summarize a bit from a zbrush book I've got - (Essential Zbrush by Wayne Robson)
They're called subtools - it's a designated area of a model that is created by appending, splitting, or extracting polygons. In old version of zbrush you could only work on one polygon mesh to sculpt at any time. Version 3 introduced subtools.
Now you can, for example, extract as a subtool each item of clothing a character has on, as well as specitif elements such as eyeballs. What this does is separate each part so that if we are sculpting on one subtool and go near the edge where it intersects with another subtool, we are prevented from making changes on the other one. This means the dangers of geometry running into each other are minimal if you take care.
There are a few ways to create subtools. You can import an entire model as a subtool. For example, you may have been working on a male anatomy study and have been sculpting a pair of boots. You can open both tools and import the boots as a subtool to your main anatomy study. The SubTool section of the Tool pallette also allows you to extract geometry from a painted mask as a brand new part that is automatically set as a subtool.
The use of subtools also gives us teh ability to hide and show parts that we need so we don't need to have everything visible all the time while sculpting. Subtools give you a way to get past your computer's maximum number of polygons.
You append a mesh to your existing sculpt by clicking on the InsertMesh button in the Geometry section of the Tool pallette. But to use it you must first have another tool loaded into Zbrush (as well as the one you are inserting into), and follow a few basic rules.
One very big thing to bear in mind before attempting this is that each tool must have the saem number of subdivision levels (either more than one, which is ideal because it allows you to continue to step up and down subdiviions levels, or only one subdivision level.) When you add another mesh in this way you are most likely to have a clear line where they join together. But luckily Zbrush has a special type of brush that allows you to melt these areas together so it is not noticable.
The clay family of brushes (Clay and Clay Tube) will let you melt your geometry together where two previously seperate meshes meet.
You can also use the MeshInsert Dot and MeshInsert Fit brushes to insert a piece of geometry, but these are usually more suited to a repeating theme such as adding bullets to ammunition belt.
To add a subtool to an existing sculpture you must first load both tools into Zbrush. Please make sure that you use the Load Tool button in the tool pallette. If you import another obj over an existing model, some very nasty things can happen.
Modeled the base mesh in 3dsmax, saved it as an obj and imported that into zbrush. As for how to make it so it's 3d and you can rotate around it, you have to go into edit mode by hitting the T key. Otherwise you're stuck in 2.5D and painting on the canvas with depth information... which I -personally- find absolutely worthless. But some people use it to create tile-able texture maps with a depth map and use that to generate a normal map, so I know it's not totally worthless... I just don't ever use it for that.
Anyway, Zbrush's user interface -IS- extremely unintuitive, although it's better if you're using an Intuos or better wacom tablet (Intuos because they have the snazzy buttons). Zbrush was designed for minimal keyboard use, so all of it's controls are attached, by default, to the small collection of buttons on the tablet, and the rest is done by different combinations of holding or releasing the pen buttons and dragging.
I'm using zbrush 3.5, although one of my coworkers is a beta tester for pixologic and I've seen 4.0 and some of it's crazy new features.
If you want to give zbrush a try, take your obj file, under the Tool menu (by default, it should be at the right-hand side of the screen towards the top) and click Import. That will let you load an obj file as a tool. Then you can click and drag on the canvas (I recommend holding Shift so it'll keep it straight). THEN hit the T key to made it an editable mesh. The buttons along the right-hand side of the canvas are useful. Find the one that says 'Frame' and click it. It'll frame the model so you can see it properly.
And from that point, you're ready to actually try messing with stuff.
Masking is done by holding the Ctrl key (or it's equivalent on your tablet) I use masking A LOT. It takes a while to work out all it's uses. Right-clicking in the canvas brings up the brush options like the size and the opacity (which is called ZIntensity or something equally unintuitive).
Also, I think the original purpose of ZBrush was to be a painting application the uses depth (hence Zbrush), but people just took advantage of it's exceptionally good 3d detailing. So I wouldn't say 2.5D is worthless, it just doesn't come into play too much with what you need ZBrush for. ;D haha