September 26, 2011
Sculpting In ZBrush 101 – Part 1
Hi and welcome to this series on sculpting in Pixologic ZBrush. In this series, we will investigate some of the game-changing techniques that have made ZBrush so popular among digital artists.
First, a quick primer on what ZBrush is. ZBrush is a digital sculpting and painting application (Autodesk Mudbox is another software package that offers similar capabilities). 3D sculpting means that you work on “digital clay”. You start out with a clay-like basic shape, like a sphere, and then you use a set of brushes to “sculpt” that clay. What makes ZBrush so powerful is that you can work on millions of polygons. In short, 3D sculpting is a very efficient and fun way to create high-polygon 3D models and/or normal-maps.
OK, enough with the sales pitch: let’s get to it!
There are basically two ways to start sculpting in ZBrush. One: make a simple “base mesh” in an external 3D application (such as Maya). Two: start with a simple shape or ZSpheres. ZSpheres are very cool, and we will save them for a later tutorial. In this part of the series we will start by importing a base mesh from Maya. You can refer to this tutorial if you need a refresher on Maya.
Creating a base mesh
There are basically three criteria for the base mesh:
- Keep it simple
- Shape it into a very abstract representation of your design
- Make sure the mesh is clean and quads only
So, you may either have some concept drawings or a mental image as reference for your design. Then, block out a simple mesh in Maya that resembles that design, using only a handful of polygons. Now, this is very important: keep it clean and all quads. You will face quirky problems in ZBrush if your mesh does not satisfy this condition. All quads means that each polygon should have four edges (this has to do with the subdivison algorithms in ZBrush). Also: the mesh should not contain any holes, gaps, overlapping vertices or polygons with flipped normals. A good reference might be the section on cleaning up the mesh in my Maya tutorial series.
In the image below, I have created a base mesh for “Headmistress Daggerhorn”, which is one of the key characters featured in the game Evil Junior which I’m currently working on. It was created on top of great concept art from Atle Mæland as the reference.
Create your own base mesh, and then export your base mesh as .OBJ in Maya. Brace for impact in ZBrush!
Intro to ZBrush
Time to open ZBrush. Hit “Import” in the tool menu and browse to your .OBJ base-mesh. “Draw” your base mesh onto the canvas by click-dragging in the viewport. Then hit “T” to edit the object.
Now, a brief heads-up on the ZBrush interface (see the picture below). To your right you will find the “Tool” and “Geometry” menu. Current brushes and materials are located to the left. Here is what you need to know:
- Tool: Here you “Import” your base mesh. You save your work as ZTools by hitting “Save As”. Saved ZTools are loaded with – surprise! – “Load Tool”.
- SubTool: You can also import several sub tools and append them to your main tool, so that you can more easily hide and select individual objects on screen.
- Geometry: ZBrush “subdivides” your mesh when you hit “Divide”. Each division operation adds resolution to your mesh, measured as the number of “active points” in the HUD of the viewport. You can easily jump between subdivision levels by hitting “Lower Res” and “Higher Res”.
- Brush and material: Here you can edit your current settings for brushes and materials.
ZBrush both looks and feels like something out of this world. (You will probably either love or hate the interface.) I would highly recommend you to use a pressure-sensitive pen and tablet for sculpting in ZBrush. Here is how to navigate:
- Sculpt: LMB onto the mesh.
- Smooth: SHIFT+LMB onto the mesh.
- Quick-menu: RMB.
- Move: ALT+LMB in the background.
- Rotate: LMB in the background.
- Zoom: ALT+LMB in the background, then release ALT and hold LMB.
- Snap rotation into orthogonal view: Rotate and then hold SHIFT.
Here are a few hints to kickstart the sculpting process:
- Symmetry. Hit “X” to enable automatic mirroring.
- LazyMouse: Hit Stroke -> LazyMouse to enable computer-aided stability to your strokes. Hands like a surgeon!
- Brushes: Some brushes you may find useful are the Standard, Smooth, Move, mPolish, and Slash brushes.
- Strokes and alphas: Try experimenting with these to customize your brushes. You can add high-res details by painting an alpha in Photoshop and then apply it to your mesh using the Drag Rect stroke.
- Material: Try using other materials other than the very “ZBrushish” MatCap Red. All the MatCap materials are good. Switch between them to apply different effects to your mesh.
- Iterate: This is perhaps the most important thing in ZBrush. Only subdivide your mesh when you have maxed-out the current level of resolution. Iterate and add more detail for each subdivision level.
- Reference: The use of reference (anatomy guides, bodybuilding magazines, images on the web) can make all the difference. Study the anatomy of bones and muscle if you find the time. Be aware of nudity though.
- Masking: Hit CTRL+LMB or ALT+LMB onto the mesh to paint masks. Very powerful for adding details. You have more options under the “Masking” menu.
Basic sculpting in ZBrush
The sculpting process in ZBrush is actually very simple. It all boils down to iteration. In the beginning of the sculpting process, try using the Move brush to drag the mesh into the shape you want. You can also ALT+LMB with this brush to push or pull. When you are satisfied with the overall shape, use the Standard brush with LMB and ALT+LMB to paint detail at the surface. Use the Smooth brush in between to make the surface nice and clean. (You may want to dial down the brush modifier on the Smooth brush to make it less sensitive.) When you are happy with your sculpting at this level, subdivide and repeat the sculpting process. You can keep on subdividing like this till you drop – or more probably – you run out of RAM. Two million polygons should suffice – any more than that and your RAM will probably choke. As I gradually add more and more resolution for each iteration, I tend to use the brushes in the following manner:
- Move: I use this mostly at low resolutions to pull and push the clay into shape.
- Standard: This brush I tend to use at all resolutions, gradually decreasing the brush size for each subdivision.
- Smooth: I use this ALL the time.
- mPolish: Great to use at higher resolutions to flatten out a surface. Especially if you aim for a cartoony look.
- Slash: At very high resolutions you can use this brush to add scars and such.
- Pinch: Very nice for pulling two edges towards each other, for example if you want to “tighten” a scar.
In the picture below you can see how Daggerhorn takes shape from a simple base mesh to a high-ploygon bust of the Headmistress of Gloomcraft Academy.
Piece of cake. Now, post an image of your sculpt in the gallery and stay tuned for the next installment! See you around :)
Oh, and one last thing: Here is an all-exclusive and yet unreleased work-in-progress of Headmistress Daggerhorn from Evil Junior!