Apr09
2014

By: Elyse                Categories: 3D AnimationBooks

This tutorial is brought to you by Getting Started in Zbrush.

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The Stroke menu setting changes how the brush is applied to the surface. This is the left tray icon second from the top, just underneath the brush icon. The default setting for the standard brush is the Dots setting, which repeats the brush’s alpha along a given brush stroke line. Click on the Strokes pop-up menu to see the other available options.

For a much smoother stroke, use the Freehand setting. When ZBrush draws a stroke upon the surface it is repeating the brush alpha along the line of the stroke. The freehand stroke provides a much more tightly spaced interval of your brush alpha, creating a more continuous line. Pick a brush alpha and change the stroke to Freehand to try it out. At the bottom of the Stroke pop-up menu there are a number of sliders and buttons for modifying the behavior of each stroke. The Mouse Avg slider adjusts the smoothness of the brush stroke by averaging out the mouse’s position slightly before applying each stroke with higher values, providing a smoother movement.

The other stroke options include DragRect, Spray, ColorSpray , and DragDot . DragRect lets you control the size and orientation of each individual brush alpha you place on the model. Simply select it and click and drag the shape out on your object. As you move the mouse around while you drag out the shape you will notice how you can control its orientation.

DragDot is a quicker way of placing the same brush alpha individually. DragDot let you interactively place one copy of your brush alpha at a time. It is very similar to DragRect but sacrifices some control for speed of placement.

FIG 5.7 Brush Stroke pop-up menu

FIG 5.8 LayerRoll brush and Alpha 58

FIG 5.9 Using DragRect stroke and Alpha 62 to create scales

By this point you should have a fun little sculpt that you’ve made and you are happy with. If not, then take some time to go back through the tutorial and create a small cartoon head sculpt to practice with. Make sure before you proceed that you have turned DynaMesh off ( Tool.Geometry.DynaMesh ) and you will also want to subdivide your model once or twice ( Tool. Geometry. Divide or CTRL D ) to get enough surface resolution to work with, say around 0.5 million active points. Click on the Alpha icon and choose Alpha 62 from the pop-up menu. Now go to the Stroke menu and choose DragRect. Click and drag your mouse on your model to apply one instance of the brush alpha. You can control the size and orientation of the alpha on the surface by dragging the mouse around while still pressing the left mouse button (LMB). The edges of the alpha are a bit strong, so let’s fi x that. Undo ( CTRL Z ) and set your brush’s Focal Shift on the top shelf to around 50. Now try it. The edges of the alpha fade out near the rim. Another way to accomplish this is to go into the Alpha menu at the top left of ZBrush’s menu bar and set the Rf , or radial fade, value to around 50. Very frequently there are multiple ways of doing the same thing in ZBrush. It boils down to a matter of personal preference and the subtle differences in effect as to which one you prefer to use. You can now go in and apply a very interesting scale pattern to your creation! Leave some blank spaces, though – we’ve got some more tricks to use.

A quick and dirty way of applying a lot of texture fast is to use the ColorSpray or Spray strokes. Spray and ColorSpray shower the model with a blast of multiple brush alphas at the same time in a chaotic spread pattern. ColorSpray varies the hue of the currently selected color, while Spray varies its value. Both are quite good for achieving a broken-up natural look to your brush strokes. Using the same alpha as before, change the stroke to ColorSpray . Set the Z Intensity to around 10 or so. The texture will build up very quickly, so we want to start with a lower setting than the default one. Now you can very quickly go and fill in the blank areas. Even though you are using the same alpha as before, you will notice that you achieve a very different look to the texture you create.

If you find that your cursor is jumping around too much and is difficult to control there is one option you can turn on to fi x this. Go to the Stroke menu and turn on the LazyMouse button. This averages the mouse position as you draw to produce a much smoother stroke. You can strengthen the effect by increasing the LazySmooth setting underneath the LazyMouse button. You should see a thin red line trailing your cursor now which can help you to visualize what the LazyMouse button is doing. With LazyMouse on, small jumps and twinges in your strokes will be minimized. The other use for LazyMouse is to draw a straight line!

FIG 5.10 Using Spray stroke and Alpha 62 to create fine texture detail

FIG 5.11 LazyMouse

FIG 5.12 Creating the eyeball with the Standard brush, DragRect, and Alpha48

We can use the DragRect stroke to create eyes for our fi rst model. Set the stroke to DragRect and choose Alpha 48 for your brush alpha. Put your Z Intensity to a value of 25. Now click and drag out a rough eye shape in the socket for the eye. Press 1 or go to Stroke.Modifiers.ReplayLast to repeat the stroke and shape out the eyeball to the level desired. You can use the Smooth brush (press and hold SHIFT to access the smooth brush) to get rid of any rough spots. Now you can change brushes to DAM_Standard and carve in the wrinkles and creases around the eye. Use the Standard and Inflate brushes to refine the eyelids and add more detail. Don’t forget to add some texture to the eyelids using your spray stroke as well.

For the pupil I chose the ClayTubes brush and gave it a round alpha with a soft edge like BrushAlpha, then set the stroke to Freehand. Now just hold down ALT and carve the iris into the middle of the eye. Press SHIFT to smooth away any irregularities. You don’t want to have a lumpy eyeball after all! Save your fi le using Tool.Save As. The ClayTubes brush is a good choice anytime you need to bulk up a feature on a model. Notice how the ClayTubes brush acts diff erently than the Standard brush we were previously using.

FIG 5.13 Use DAM_Standard to create the wrinkles around the eyes

FIG 5.14 Use the ClayTubes brush, Freehand stroke, and BrushAlpha alpha to create the iris

Problems and fixes When sculpting you want to avoid pulling a surface through itself. This is where one part of a model starts to push through the opposite side of the model, inverting it. This can become very difficult to work with and should be avoided. If you see your model turning itself inside out, simply undo or load an earlier version of the model. Another issue that frequently pops up is that of working on very thin surfaces. Each brush is actually a sphere shape, not just the flat circle indicated by the brush cursor. When you sculpt a thin surface the brush will, by default, aff ect the back side of the surface as much as the front! To avoid this you can turn on Brush.Auto Masking.BackfaceMask . Backface masking will automatically turn off the brush’s effect on the side of the surface facing away from you.

Well, that’s a solid introduction to the major features of sculpting in ZBrush. We will be returning to some of these points later on and expanding upon them; but for now we should be able to move on to the next phase of applying materials to and painting our model. Don’t forget to save your model now.

FIG 5.15 A common error and Backface Masking

Excerpt from Getting Started in Zbrushby Greg Johnson  © 2014 Taylor & Francis Group. All Rights Reserved.

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