Sculpting With Primitives

Strokes

While sculpting polymeshes in 3D you can use 6 different types of strokes: Dots, DragRect, Freehand, Colorized Spray, Spray and DragDot. These can be used with the alpha sculpting feature.

Below, left to right; Dots, DragRect, Freehand, Spray, and DragDot stroke types, sculpted onto a plane in 3D Edit mode. The DragRect stroke started at the center of the circle, and was dragged out; all other strokes started at the top left, and were dragged to the lower right.

Using DragDot

A DragDot stroke allows you to drag your brush around, to place your sculpting or painting at a precise point. Only the area under the mouse when the drag ends is affected.

That's very useful for a case where you might want to have a company logo or some other bit of text stamped onto the model. For our example, though, we're going to get a bit more creative so that your imagination might be sparked to try even more interesting things.

We'll need these settings:

• Brush:Std selected.
• Alpha:Brush 09 (ring-shaped alpha) selected.
• Stroke:DragDot selected.
• Transform:Z on, to activate Z symmetry
• Transform:(R) on, to activate radial symmetry.
• Transform:RadialCount = 8.
• Draw:Z Intensity = 80.
• Draw:Draw Size = 64.

Now:

1. Click Tool:Layer:New to create a layer that we'll edit on.
2. Use Tool:Layer:Rename and change the layer's name to DragDotLayer.
3. Click on the column and drag your stroke down to a point near the bottom as shown below.

Draw again to get this:

As you can see, this stroke allows us to very easily create an intricate pattern with only a simple alpha. What's especially nice about this stroke is how precise it is. You can place your alpha instance(s) in exactly the desired position.

Using Dots

This stroke draws a great many instances of the alpha very close together so that they blend into a single line. The closeness of each alpha to its neighboring instances is determined by how quickly you move the mouse. A slow stroke will create a uniform line (especially when lazy mouse mode is active), while fast movement will create a blotchy effect that is useful for some organic work.

For this example, we're going to use the stroke to add some rings around the column, separating it into sections.

Set:

• Brush:Std selected.
• Alpha:Brush 12 (ring-shaped alpha) selected.
• Stroke:Dots selected.
• Transform:Z on, to activate Z symmetry
• Transform:(R) on, to activate radial symmetry.
• Transform:RadialCount = 100.
• Draw:Z Intensity = 20.
• Draw:Draw Size = 5.

After everything is set up, just:

1. Create a new layer by pressing Tool:Layer:New.
2. Rename it by pressing Tool:Layer:Rename, call it DotsLayer.
3. Draw some narrow rings around the column as shown in the following figure.

Keeping the same settings as above, set:

• Draw:Z Intensity = 15.
• Draw:Draw Size = 10.

Add a few more rings as shown in below. Don't be afraid to keep going over the same area to build up additional width or depth.

Now let's sculpt a bit of a design on the very top of the column.

Otherwise keeping the same settings as above, set:

• Alpha:Brush 01 (ring-shaped alpha) selected.
• Transform:RadialCount = 6.
• Draw:Z Intensity = 35.
• Draw:Draw Size = 20.

Now just three strokes will add the sculpting shown below.

Using DragRect

The Drag Rectangle stroke draws a single instance of the alpha, which may be rotated while dragging the stroke. The alpha is drawn with its center point being where the stroke begins. As you move the mouse away from the starting point, the alpha becomes larger. As you move the mouse around the starting point, the alpha is rotated.

Set up for drawing with:

• Brush:Std selected.
• Alpha:Brush 29 (three stacked arrows) selected.
• Stroke:DragRect selected.
• Transform:Z on, to activate Z symmetry
• Transform:(R) on, to activate radial symmetry.
• Transform:RadialCount = 6.
• Draw:Z Intensity = 50.
• Draw:Draw Size is irrelevant; the size is determined by your mouse movement.

1. Create a new layer by pressing Tool:Layer:New.
2. Rename it to DragRectLayer by pressing Tool:Layer:Rename.
3. Now draw a stroke that begins a little below the upper set of rings. Drag straight down until the arrows almost touch those that are also being drawn to the left and right. When the size is right, move the pointer left or right a bit to ensure that the arrows point straight down along the shaft of the column, and release the mouse. The result will be as shown in the next figure.

1. Repeat this just above the next set of rings down. Drag your stroke upwards to point the arrows toward the top of the column.

As you can see, the DragRect stroke type is perfect for stamping any sort of design onto the model. Another use would be with a speckled alpha to draw pores on a person's skin. Because you control the size and orientation of the alpha with every stroke, you can keep the stamps from repeating, thus preserving a naturally organic appearance.

Using Freehand

The Freehand stroke type is very similar to Dots, but gives you precise control over how far apart the instances of the alpha will be stamped.

Set:

• Brush:Std selected.
• Alpha:Brush 18 (ring-shaped alpha) selected.
• Stroke:Freehand selected.
• Transform:Z on, to activate Z symmetry
• Transform:(R) on, to activate radial symmetry.
• Transform:RadialCount = 6.
• Draw:Z Intensity = 60.
• Draw:Draw Size = 20.
• Stroke:Spacing = 1, to cause individual applications of alphas to be mostly overlapped. (Higher values would result in less overlap.)
• Stroke:Lazy Mouse selected, to result in smoother lines as you draw.

1. Create a new layer by pressing Tool:Layer:New.
2. Rename it to FreehandLayer by pressing Tool:Layer:Rename.
3. Now draw a single line down the side of the column. It may help to rotate the model onto its side before doing this.

The Freehand stroke type is remarkably useful any time you want to draw lines of repeated detail. You could trace a line of rivets along the seams in an aircraft's panels, create cute little swirls of dots, etc.

Using Spray and Colorized Spray

These two stroke types splatter the model with semi-random copies of the alpha. There are settings to determine how far apart the alpha instances can be, how much they fluctuate in scale, how densely the instances are drawn (just a few scattered, or a lot), and how color is affected. The difference between the two stroke types is specifically in how each deals with color. Spray will cause the value of the currently selected color to fluctuate. Colorized Spray will affect its hue. Since we're strictly sculpting in this tutorial, the color modifications don't play a role and so we could use either stroke with exactly the same results. We'll just use Spray.

Set:

• Brush:Std selected.
• Alpha:Brush 04 (like a puff of cotton) selected.
• Stroke:Spray selected.
• Transform:Z off.
• Transform:(R) off.
• Transform:RadialCount = 6.
• Draw:Z Intensity = 30.
• Draw:Draw Size = 20.
• Draw:Zsub = selected.

1. Create a new layer by pressing Tool:Layer:New.
2. Rename it to SprayLayer by pressing Tool:Layer:Rename.
3. Now simply draw some damaged spots on the column.

The Spray strokes are a very powerful way to quickly create randomized organic detail. Don't forget that while we've used them strictly in a modeling capacity in this tutorial, they also work quite well with polypainting. That's where you'll really put the color features of these stroke types to good use.

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Alphas

An alpha is a grayscale intensity map. It can be used to represent intensity, masking, and similar things. For example, bump maps and displacement maps (both in ZBrush and in other programs) are both alphas; the gray intensity represents the height or depth of the bump or displacement.

Note: ZBrush alphas are 16 bits in depth, which simply put means that they can produce much smoother gradations in gray, and hence wherever they used. Some other programs are limited to 8-but alphas, which can produce noticeable 'stairstepping' artifacts.

In ZBrush, alphas are used for much more than just bump or displacement maps. They can affect masking (which parts of an model or painting you work with), brush appearance, how colors, or materials are laid down, and the shape of sculpts. And probably a few other things I can't think of right now.

In addition, you can make your own alphas, and also turn alphas into other tools, such as Stencils (which are masking tools that offer a different, and powerful, set of capabilities).

Below, we describe the most common ways of obtaining and using alphas. We also give links to pages which describe material significantly related to alphas.

Note: The Alpha Palette details all of the controls found in that palette, but you will also find alpha-related controls in other palettes.

Using Alphas

• Many of the standard drawing tools use alphas to control their shape. This affects the depth of pixols on the canvas.

• Alphas may be used with 3D sculpting brushes to affect the geometry of 3D models.

• Alphas are the means by which displacement and bump maps are exported from ZBrush. The Alpha Displacement Exporter adds further power to this process.

Obtaining Alphas

First and obviously, ZBrush comes with a large selection of useful alphas, which can be selected from the Alpha Palette (menu) in the menubar, or from the popup inventory to the left of the canvas.

You can of course load your own images for use as alphas using the xxx in the Alpha menu. Colored images will be converted to grayscale.

Note: Some image file formats do not support 16-bit grayscales. If you load such files, you may get the stairstepping effect described earlier. When using external programs to create alphas, try to use one that offers 16-bit grayscales.

You may find it more convenient to simply paint a pattern on the screen, and then use the xxx control to convert it into an alpha. The depth of the scene you created will be converted to the alpha (color will be ignored). Since ZBrush supports 16-bit depths, you will get a true 16-bit alpha.

Note: Alphas are displayed as thumbnail images in the alpha popup chooser, but are always saved with the full dimensions of the source image from which they were created. To get a small alpha, you can paint it on a large canvas of the proper aspect ratio, and then reduce the canvas size before making the alpha. Alternatively, a large alpha can be useful when you want to repeatedly apply a lot of detail repeatedly over large areas.

Other Points

• The popup that displays the current inventory of alpha functions similarly to other inventory popups, such as the Tool popup. For example, ZBrush can hold a maximum of 256 alpha at any given time. If you load or create more alphas than this, then each new alpha will replace the currently selected alpha. For more details on inventory behavior, see xxx.
• A good library of very useful alphas is available as a ZBrush plugin at xxx.
• Alpha are crucial for obtaining the very fine detailing for which ZBrush is known; See Projection Master.
• If you need to rotate an alpha, you can convert the alpha to a Stencils Stencil, and use the stencil instead. Or, if it makes sense, you could simply rotate the model appropriately, and then apply the alpha.