Learning ZBrush 4 – Clearing the confusion
Category : 3-D Modeling
When I first used ZBrush, I found many things confusing. ZBrush doesn’t quite operate the same way as other 3D applications. Its a cross between a painting program and a 3D modeling program hence the name ZBrush; “Z” for depth and brush for painting. This series begins with things that might confuse the new user in the hope of clearing the confusion. I’ll try to avoid more advanced terminology until later in the series. Some of these tips will make more sense in my next article when we actually begin sculpting. I still think its important to keep these tips in mind before you begin.
1. Scale vs Zoom
Prior to ZBrush 4r8, ZBrush confused me initially because the button labeled zoom only increased the size of the draw window slightly. I discovered that to do real zooming, I should use the scale feature instead.
Scaling is also essential for getting high resolution detail onto a model. Additionally, scaling an imported object file inside ZBrush will not affect the size of the exported object. No other 3D program I’ve used behaves this way. With ZBrush 4r8, Scale has been re-labelled as Zoom 3D.
2. New sculpts are ZTools (*.ZTL).
Once sculpting begins in ZBrush, the object being sculpted becomes a ZTool. Pressing ‘T’ on your keyboard or clicking the Edit button at the top will toggle a ZTool in and out of 3D and 2.5D mode. Switching a tool to 2.5D mode is called “Dropping to canvas”. Switching to 3D mode is referred to as “Picking up from Canvas”.
When a ZTool is in 3D mode it can be painted, rotated in 3 dimensions and sculpted. When it is in 2.5D mode the only change is that rotation is restricted to 2 dimensions. 2.5D mode allows photographic detail to be projected onto a model. ZBrush will retain this detail when the tool goes back to 3D mode. Another advantage is that high polygon models can easily be turned into background images thus lowering the overhead for a 3D render.
ZBrush 4 adds a new file format similar to ZTool called ZProject (*.ZPR) which stores render and material information along with the object.
3. Preserving UVs
If you plan to create textures in ZBrush, make certain that none of the object parts have overlapping UVs. Overlapping UVs result in streaked texture maps with paint from one part of the object ending up on a different part. Various tools can be used to separate the UVs into sections that fit on a single square. Silo would be good choice for this purpose.
A free alternative is the UV Master plugin available on Pixologic’s plugin page. A free alternative is the UV Master Plugin now bundled with ZBrush.
4. Always lower brush intensity.
Always turn brush intensity to the lowest level and gradually increase it when sculpting or painting. This provides maximum control over the model being sculpted or painted and allows an artist to create more subtle details. RGB Intensity affects the strength or opacity of color brush strokes and Z Intensity controls the depth of sculptured brush strokes.
5. Paint and sculpt at hi-res; export the model at low-res
Always set the highest possible resolution when painting and sculpting. This will capture the most detail for your model in combination with scaling. Increasing resolution is also called subdivision. If you plan to use your model with programs other than ZBrush, you will have to export it is a low-res OBJ file. Most programs cannot handle the million plus polygons in ZBrush. To preserve your sculptured detail, you can export the detail as a normal map or a displacement map. This has been made easier in ZBrush 4 with the Multi-Map Exporter plugin.
6. Always turn on perspective.
This seems like a no-brainer but new users may miss the perspective button in ZBrush’s dense interface (its on the right-hand side underneath “AAHalf” and above “Floor”) . This tip is especially important when sculpting portraits for use in other 3D programs. Faces will look more rounded and stretched when viewed in perspective.
7. Use a drawing tablet.
ZBrush is designed for tablet use. A Mouse gives far less control over the brushes than a tablet. Wacom has a wide selection of drawing tablets.
8. Focal Shift controls the softness or hardness of a brush.
The cursor on ZBrush looks like two circles. The inner circle represents “focal shift” and the outer circle represents brush size. If the focal shift circle is close to the same size as the brush size circle, sharp edges will define the marks of the brush (hard brush). If the focal shift is small compared to the brush size, the brush will will be smoother and edges will be smudged (soft brush).
9. Use Clipping and Masking for hard surfaces and straight lines.
Masking allows an artist to freeze parts of a ZTool so that it is not affected by the sculpting and painting brushes. Clipping will “squish” the virtual clay of a ZTool to fit a particular shape, much like using a mold or cast with real clay. Masking has been part of ZBrush for some time but clipping is a new feature of ZBrush 4. For best results go to the highest resolution level in ZBrush when making hard surfaces and straight edges. Clipping and Masking can be used to create extremely complex shapes in conjunction with ZBrush’s new Shadow Box feature.