Drawing Tools
From ZBrush Info
List of Pixol (Drawing) Tools
Pixol-based tools let you create or modify pixols in the document. With these tools, you can transform pixols in the document by changing their depth and/or X/Y position. At the same time, or alternatively, you can use these tools to change pixols' color and/or material.
Each pixol-based tool is covered in its own section on the following pages:
Simple Brush
The Simple brush is the default tool, active when you first start ZBrush. While it can be used for adding pixols to the document, it's best used for modifying depth and/or color and/or material information in an existing drawing. If you turn off the Z options in the Draw palette, the Simple brush acts very much like a standard brush in other painting software.
The best way to think of the Simple brush is as a tool that adds to and blends with existing depth information in the drawing. For example,
Here, the Simple brush was used to draw a gold stroke on top of the existing gray ring. Note that the depth information already present in the drawing was not erased, but simply added to.
Following are several additional important points about Simple brush functionality:
- It's not sensitive to abrupt changes in depth in the drawing, so the Z Tolerance setting has no effect. In other words, it affects all pixols equally, regardless of depth. For an example of this, See “Sphere Brush” on page 113. There, the Simple brush is compared with the Sphere brush.
- It requires that the Draw palette:RGB Opacity and Z Opacity settings be the same. Thus, when using the Simple brush, you cannot turn off the Draw palette:Lock RGBZ toggle.
Single Layer Brush
The Single Layer brush is very similar to the Simple brush. The main difference is the ability to limit the impact of each brush stroke to the current setting of the intensity value. This brush applies only one coat of paint/depth with each brush stroke. It doesn't build up color intensity or depth with overlapping strokes unless you pick up the stylus or release the mouse button between strokes.
Even where continuous strokes cross over themselves, the depth of all parts of the stroke remain the same. Image:Drawing Tools singlayer-monitor.jpeg
In the image below, four brush strokes were drawn on top of four identical spheres. The top-most stroke used an intensity of 100%, which caused the color of the stroke to fully overwrite the existing sphere color. The second stroke used an intensity of 75%, which resulted in a final color composed of 75% of the stroke color plus 25% of the existing sphere color. The next stroke used 50%, which resulted in an even blend between the brush and the sphere colors. The last brush stroke used an intensity of 25%, which resulted in final color composed of 25% of the stroke color plus 75% of the existing sphere color. 
Sphere Brush
The Sphere brush lets you draw with a mathematically calculated hemisphere, so that its edge is always perfectly round, no matter how big you make it. This brush is ideal for building up smooth-edged volumes in the drawing. For best results, move the mouse or tablet stylus in small circles as you draw.
As with the Simple brush, RGB Opacity and Z Opacity sliders are always locked together with the Sphere brush. Also, the hemisphere it uses is always perpendicular to the background. The Alpha brush is the exact same brush, but it lets you use any Alpha image.
Figure quickly sketched out with the Sphere brush.
Unlike the Simple brush, the Sphere brush respects the depth information in the document, and uses it for auto-masking.
In the illustration below, we started with two spheres on a purple background. On the right-hand side, we drew with the Simple brush on the background and intersected the sphere. On the left-hand side, we drew the same stroke with the Sphere brush. Note that the Simple brush stroke partially covers the sphere, even though it started in back of it. However, the Sphere brush takes the depth priority into account, thus allowing the sphere to mask the brush stroke.
Modifiers:
Color Blend: Enables/disables color blending at the brushstroke edges.
Alpha Brush
The Alpha brush is, like the Sphere brush, useful for building up volumes in the drawing. The primary difference is that the Alpha brush can use any Alpha image for its shape.
As with the Simple brush, the RGB Opacity and Z Opacity sliders are always locked together when you use the Alpha brush. Also, the Alpha image it uses is always parallel to the background. Lastly, the Alpha brush respects the depth information in existing pixols, so that it doesn't draw over pixols that are in front of where you're drawing.
In the drawing below, the Alpha brush was used with two different Alpha images to draw from the big sphere along two of the mushroom stems. As you can see, the mushroom caps weren't covered by the Alpha brush pixols.
Use the Alpha brush tool to build up volumes using any shape of brush; add reptilian skin folds and bumps if you wish. 
Modifiers:
Color Blend: Enables/disables color blending at the brushstroke edges.
3D Brush
The 3D brush uses an alpha bitmap to create an elevation field. It uses the orientation of the surface you draw on. You would typically use the 3D brush with the default Dots stroke type to draw continuous copies of the elevation field, or with the Drag Rectangle stroke type to draw one at a time. In the former case, the size is set by the Draw palette settings, but with Drag Rectangle, you set the overall size by dragging. You can still alter the Drag Rectangle depth and aspect ratio with the Draw palette settings, and further modify the size and orientation by using the Transform palette.
Note: In addition, the 3D brush can use differing settings for RGB Opacity and Z Opacity, if you turn off the Lock RGBZ toggle in the Draw palette.
Using the 3D brush with different Alpha images. 
Modifiers:
DoubleSided: This option effectively places the alpha bitmap back to back. If you use a 3D brush set to DoubleSided on a thin object, the brush may protrude through the back side of the object. This effect is shown in the illustration below; the two brush strokes on the right side are set to DoubleSided, while the two on the left are not. Also, when you turn DoubleSided on, the tool is “solidified,” so that the RGB opacity and Z opacity are distributed evenly over the brush surface. When DoubleSided is off, relative opacity is based on the alpha mask. This is also shown in the illustration below.
The 3D brush applied with DoubleSided off (left) and on (right) 
Bump Brush
The Bump brush is similar to the Simple and Single Layer brushes, except that it uses the surface normals of any pixols you draw on with it. This is true whether you simply click to draw with it, or drag to draw a longer stroke.
The Bump brush was used to add details to the right-hand ring, with each new pixol raised or subtracted perpendicular to the surface it was drawn on.
You can also use the Bump brush in ZCut mode to subtract portions of objects realistically, because the default behavior works with respect to the surface normals. It is possible to use the picker to specify other orientations.
Below, the egg was “cut into” with the Bump brush on the left side, and with the Simple brush on the right side. The latter doesn't look quite right, because it always cuts perpendicular to the picture plane, whereas Bump cuts perpendicular to the surface it's applied to.
Modifiers:
Color Blend: This slider enables you to blend the current Main color into existing pixols, and determines how strongly the Main color is blended into them.
Constant: When this is turned on, the Bump brush moves pixols in the same direction for the duration of each stroke. The direction is determined by the surface normal of the pixol on which you begin the stroke.
In the image below, four brush strokes were applied to the golden pipe. Each stroke started in a similar corresponding point (1) and dragged down to a similar endpoint (2).
Stroke setting (from left to right)… * ZAdd with Constant turned Off. The pipe has increased its thickness. * ZSub with Constant turned Off. The pipe has decreased its thickness. * ZAdd with Constant turned On. The pipe has been pushed up. * ZSub with Constant turned On. The pipe has been pushed down.
Note: In order to correctly produce the strokes on the right, the auto-depth masking was disabled by selecting Zadd or ZSub and then turning off the Draw:Channels:Infront and Draw:Channels:Behind.
Sample Size: The Bump brush samples pixols in the vicinity of the cursor to determine the surface orientation. The Sample Size setting controls the size of the area sampled to determine orientation. When drawing on an uneven surface, use a high setting to smooth out the results, or a low setting to reflect the unevenness. Default = 1. Range = 0 to 8.
Smudge Tool
The Smudge brush moves pixols around on the screen, like pushing wet clay with your thumb. It doesn't add color (unless the Control key is pressed), but it does respect pixol depth information.
In the illustration below, blobs of pure color were placed on the canvas, then the Smudge tool was used to move pixols.
Note: If you hold down the Control key while using the smudge tool, the tool becomes the simple brush and will apply color and depth.
Below, the smudge tool was used to “smudge” the red sphere into the white sphere. The setting of active channels and masking mode affect the behavior of the smudge brush as described after the figure.
The control combination used to achieve the above effects were:
- The two spheres before applying the smudge stroke. 2. ZAdd and MRGB are on. INFRONT masking is active. 3. ZAdd and MRGB are on. Masking is disabled. 4. ZAdd and MRGB are on. BEHIND masking is active. 5. ZAdd is disabled. Only MRGB is enabled. 6. ZAdd is enabled while MRGB is disabled.
Modifiers:
Color Blend: This slider enables you to blend the current Main color into existing pixols, and determines how strongly the Main color is blended into them.
Retain Center: This button causes the Smudge tool to remember the first click when you apply the brushstroke, and retain that point as the center of smudging.
Snake Hook Brush
The Snake Hook brush pulls pixols out from the image, towards or away from the viewing plane, while using the brush motion to shape the extrusion profile. For instance, you can create spiral or wavy extrusions by moving your cursor in the corresponding way.
This image started as a single orange Sphere that was drawn in the bottom portion of the image. The Modifier “Color Blend” was set to a high value and colors were changed for different areas of the plant.
The depth that the extrusion ends at depends upon your Draw palette settings. Zadd will pull the pixols toward you, while Zsub will push them away. The amount of depth change is controlled by the Z Intensity setting.
Modifiers:
Color Blend: This setting determines how the current Main Color (in the Color palette), or the currently selected Texture Colors interact with the existing pixol color. The lower the value, the more existing pixols retain their original coloring, and the higher the value, the more they take on the Main Color coloring. Default = 50%. Range = 0% to 100%.
Main Color= Red: Color Blend= 0% (left), 50% (center), 100% (right). 
Resolution: ZBrush automatically sets the resolution of the brush. This setting is a multiplier that increases the sub-division of polygons at higher values, resulting in smoother surfaces with slower rendering speeds. Default = 0. Range = 0 to 3.
Eraser Brush
The Eraser Brush paints with the background color and the background depth using the selected alpha shape and the RGBZ intensity setting.
Erasing by using various Alpha and Intensity settings. 
Note: For a more gradual erasure, set Draw:RGBZ Intensity to a low value.
Hook Brush
The Hook brush, like the Snake Hook brush, lets you pull pixols out of the image toward the viewer, but it interprets your cursor motion differently.
The basic technique is to drag in one direction to in order to set the length of the extrusion, and then without releasing the mouse button, drag in a reverse direction to set the angle of the extrusion. If the second drag is in the opposite direction of the first, and the same distance, the extrusion ends up pointing straight out at the viewer.
In the image below, the left-hand extrusion (1) was produced by applying the Hook brush in one direction only, while the right-hand one (2) was the result of dragging right and then left. 
Use the Hook brush to create straight-line extrusions in any direction
The Hook brush has a special scaling capability that you can apply by twirling the cursor in a circular direction at the end of the stroke. If you move the cursor clockwise, an expansion or increased separation occurs (depending on the Alpha image); if you move the cursor counter-clockwise, a shrinking or moving together occurs. The longer you move the cursor, the greater the effect.
Using Alpha 07, the Hook brush was used to pull perpendicular to the sphere (1), then reversed direction to point the spikes toward the viewer (2), then with clockwise rotation to scale (3). 
Modifiers:
Color Blend: This setting determines how the current Main Color or Texture interacts with the existing pixol color. The lower the value, the more existing pixols retain their original coloring, and the higher the value, the more they take on the Main Color coloring. Default = 50%. Range = 0% to 100%. (See “Snake Hook Brush”.)
Resolution: ZBrush automatically sets the resolution of the brush. Default = 0. Range = 0 to 3.
Fiber Brush
The Fiber brush lets you add 3D hair-like strands to the image. It respects the surface normals of pixols you draw on, and, by default, draws the hairs perpendicular to the surface. You can use the orientation picker to change to another mode. The Draw Size setting controls the size of the brush and the length of the fibers is controlled by the Depth setting.
Note: The RGB Opacity setting defaults to 50% and the Z Intensity setting to 95% when you choose the Fiber brush. Set them higher for coarser fibers, or lower for finer fibers. Also, adjust the fiber length with the Draw:Depth setting.
Modifiers:
Density: Controls the number of fibers produced. Default = 19%. Range = 0% to 100%.
Gravity: This setting lets you apply gravity or anti-gravity to the fibers. With Gravity set to a negative amount, the fibers curve upward. With Gravity set positive, they curve downward. Set the 0%, Gravity has no effect, and fibers stick straight out from the surface they're drawn on. Default = 19%. Range = -100% to 100%.
Gravity set to: -100% (left), 0% (center), and 100% (right). Image:Drawing Tools fiber-gravity.jpeg
Grooming: This setting lets you “comb” the hair—that is, you control the fiber angle by the direction you draw in. The higher the setting, the more the angle is influenced by drawing direction. Default = 0%. Range = 0% to 100%. In the illustration below, Grooming was set to 100%, and then the fibers were drawn in a circular motion.
Turbulence: You can add randomness to the direction of each fiber by increasing the Turbulence setting. Default = 0%. Range = 0% to 100%.
Flat Color: When Flat Color is on, the fibers are drawn using only the current Main color without shading.
Back Color: When Back Color is on, the fibers are colored with a gradient, starting with the secondary color at the “bottom” and going to the main color at the “top” (the end of the fibers). When Back Color is off, the fibers are colored only with the main color. Default = on.
Note: You can obtain interesting effects with the fiber brush when drawing on a multicolor surface by turning on Picker:Continuous Color. For best results, also turn off Back Color. Each fiber uses the color of the pixol it's drawn on, so you get multicolored “hair” that matches the surface it's drawn on. Colored hair patches, obtained as described above.
Source Color: When Source Color is on, the fibers are colored with a gradient, starting with the color of the object at the “bottom” and going to the main color at the “top” (the end of the fibers). Default = off.
RGB Antialiasing: When turned on, produces fibers with antialiased edges.
Thickness: Controls the overall thickness of the fibers. Range = 1 to 16. Default = 1
Shape: Controls whether the fiber is equilateral or rectangular. Range = -100 to +100. Default = 0. When set to zero, the fibers are equilateral. Negative values produce fibers that are rectangular with a greater height. Positive values produce fibers that are rectangular with a greater width.
MRGBZ Grabber
This tool lets you grab part of the image as a texture and as a gray scale depth image. Drag a rectangle over the area you wish to “grab,” starting at the center. When you release the mouse button, the color (and optionally, shading) of the area inside the rectangle is added to the Texture palette. At the same time, the depth image is added to the Alpha palette. You can then use the texture and alpha image with most other tools.
It is possible to export an alpha channel with intensity values that correspond to the depth of each pixol. This alpha channel can later be used in Photoshop (or any other program that can read Photoshop format) for depth enhanced editing (such as depth-cueing, fog, and such).
Original Object (below left) and Grabbed Depth Image (below right)
Grabbed Unshaded Texture (above left) and Grabbed Shaded Texture (above right)
Modifiers:
Shaded RGB: If this is off when you grab a texture, ZBrush uses only the base colors of the area you grab. (To see the base colors, turn on Render:Flat Render.) When you turn on Shaded RGB, ZBrush grabs the shaded colors (colors created by lighting and materials).
Autocrop: When autocrop is enabled (lit), the dragged rectangle will automatically shrink to crop out empty canvas in the grab area.
Paint Brush
The Paint Brush applies a layer of color and/or depth in a continuous stroke.
Although similar to the Single Layer Brush, it provides natural, intuitive feedback – good for sketching or drawing.
Modifiers:
Bristle Mode: Causes this brush to paint in a manner that more prominently displays the contours and patterns of the currently selected Alpha image. This allows the brush to more accurately simulate the strokes of a real-world paintbrush.
===Cloner Brush===
The Cloner brush lets you copy part of the document within a layer, or from one layer to another.
Use of the Cloner brush is a two-step process:
- Ctrl-click the center of the area that you want to copy.
- Click again in a different part of the document to set the offset distance (distance to edge) of the area you want to clone.
The second click actually draws the first stroke of the copy. To continue copying, drag without releasing the second click. Each time you click and drag again, using the Cloner brush, you make an additional copy of the original area at a distance that's a multiple of the original offset.
You can use any Alpha image with ZBrush's Cloner brush. This lets you copy the image while controlling the intensity and shape of the clone with a gray scale Alpha image.
In the image below, the third copy used ZBrush's Brush 30 Alpha image.
You can fundamentally change how the Cloner brush works with its modifiers; be sure to see the Modifiers section, below.
Note: ZBrush remembers the last offset you set and uses it throughout the current session until you set a different one. So, after setting an offset, you can clear the screen, start a new drawing, and then use the Cloner brush with the same offset.
You can achieve the same effect as multiple-click cloning with a single click-and-drag by turning on the Picker:Dynamic option. This lets you make multiple copies at equal distances from each other.
Modifiers:
Layers Mode: When this is turned on, the Cloner brush copies pixols from all other visible layers to the active layer, ignoring any pixols in the active layer. For more information about ZBrush's Layers feature, See the Layer Palette. 
Shaded: Embeds the shading into the cloned image's base color. In order to understand how Shaded works, it's necessary to know that a tool in ZBrush can derive its coloring simultaneously from many different sources including: * The base color, which can be a solid color or a bit mapped texture. * The material, which is made up of one to four shaders. The shaders modify the base color with properties such as specularity, diffuse reflection, and optionally a reflection-map image. * The Render modifiers. When the Shaded switch is active, the Cloner brush copies the shaded color rather than the base color. You can see this most easily by turning on the Render:Flat Renderer switch, which prevents display of any shading in the document, showing only base colors. If you clone an area repeatedly—which, incidentally, you can do in a single stroke by turning on the Picker:Dynamic switch—the shading is reapplied to each successive copy, becoming increasingly intense. In the illustration below, the sphere, which used the BasicMaterial 02 shader, was cloned using the Dynamic option with Shaded turned off on the top, and then with Shaded enabled on the bottom. Each successive clone in the lower row uses the shading from the previous one, so the shading is increasingly pronounced in the later clone “generations.” 
RetainCenter: By default, the Cloner brush will clone the same part of the image regardless of its offset distance. For example: Ctrl+Click on the center of a sphere, and every stroke after that will begin by cloning the center of the sphere. Turning RetainCenter off changes this behavior so that the offset distance is taken into effect. Only the first stroke after the Ctrl+Click will begin with the center of the sphere, and will set the offset distance. Subsequent strokes will maintain the same offset distance, and would paint more of the sphere. In the illustration below, the original image was drawn in the center. For the examples on either side, Ctrl+Click was performed on the tip of the upper arrow and three vertical strokes were drawn beginning with the middle one. The left example used RetainCenter, while the right example did not. 
ZOffset: When on, places cloned pixols at the pixol depth of the clone destination point. Normally, pixols are cloned at the same depth as the source pixols. Turn on ZOffset to have ZBrush use the depth of pixols at the destination, potentially resulting in a different depth for each clone. In the illustration below, the chess piece on the left was cloned six times on the tilted chess board. ZOffset was turned on, so each clone was positioned at the correct depth relative to the part of the board it was drawn on. 
===Color Correction Brushes===
Following is a list of all of the color correction brushes in ZBrush.
Each color correction brush has its own set of Modifiers sub-palette parameters, which can profoundly alter the brush’s behavior.
The following parameters are common to many of the brushes, thus are not listed in the individual entries:
Sample Size: The size of the volume that is used to evaluate the action of the brush. At a size of 5, a cube 5 pixols on each side is used for evaluation of the brush action. Range = 1 to 7, Default = 2.
As with the other brushes, the Draw palette sets values for the brush, including size, shape, opacity and effect on depth. For more information, See the Draw Palette.
Note: The action of most color correction brushes can be reversed by holding down the Alt key. Thus the Blur will become Sharpen, Intensity becomes subtract Intensity, etc.
Blur
The Blur brush is similar to a Blur filter in a paint program, with the added capability to blur depth; it simply blurs pixols that you draw over. Use it to smooth out sharp edges or abrupt color transitions.
Sharpen
The Sharpen brush is similar to a Sharpen filter in a paint program, with the added capability of sharpening depth; it simply sharpens pixols that you draw over. Use it to bring out details in an image.
Noise
The Noise brush is similar to a Noise filter in a paint program, with the added capability of applying noise to the depth channel; it simply adds random variation to pixols that you draw over. Use the RGBZ Opacity setting to determine the extent of the noise effect.
The Noise Brush was used in the image below to apply noise to a sphere and then the Blur Brush was used in order to soften the rough surface.
Base sphere then Noise applied then Blur applied
Highlighter
The Highlight brush adds color to the color already present. A continuous stroke that repeatedly goes over the same spot will push the colors all the way to white, but repeated strokes have a much more gradual effect than the Highlighter II brush. The method used is dependent on the Modifier settings.
Modifiers:
Auto Color: Samples the existing color and adds the same color to itself.
Inverse: Causes the brush to use the color complements of pixols painted upon.
White: Adds white to the existing color.
Main: Adds the color selected in the color palette to the existing color.
Highlighter II
Like the Highlighter brush, the Highlighter II brush adds color to the color already present. A continuous brush stroke will only lighten the colors once, but repeated strokes will push the color all the way to white. The method used is dependent on the Modifier settings.
Modifiers:
Auto Color: Samples the existing color and adds the same color to itself.
Inverse: Causes the brush to use the color complements of pixols painted upon.
White: Adds white to the existing color.
Main: Adds the color selected in the color palette to the existing color.
Bristle Mode: The brush stroke more closely reflects the currently selected Alpha image, allowing the stroke to more accurately resemble a real-world brush.
Intensity
The Intensity brush increases the intensity of the color it is applied to.
Glow
The Glow brush spreads color from the highest intensity color to the pixols around it.
Note: The Glow brush can be used for smoothing depth when only Z is enabled and is a better choice than the Blur brush to smooth near edges.
Colorize
The Colorize brush applies the selected color or texture.
Modifiers:
Max Intensity: When on, uses the maximum intensity of the color selected so that successive applications do not build up darkness. When off, uses the unmodified color. Default = on.
Saturation
The Saturation brush increases the saturation of the color it is applied to.
Hue Shifter
The Hue Shifter brush moves the color it is applied to across the hue range. Usually not used for dramatic change, but for slight adjustments, such as adjusting skin tone.
Modifiers:
Shift Rate: Adjusts the amount and direction of shift
Alpha Shift: Shifts hue by an amount determined by the applied alpha channel.
Shading Enhancer
The Shading Enhancer brush is used to add or subtract “shine”. In a rendered image, shading is calculated mathematically. Use the Shading Enhancer to make small corrections or additions or to make the image more painterly.
Modifiers:
Intensity: Amount of effect. Range = -100 to +100. Default = 50. Negative values subtract shine.
Custom Filter III & V
The Custom Filter brushes apply customized effects to the pixols over which they are drawn. These filters employ convolve algorithms so you can use them to achieve such effects as blurring, sharpening, embossing and adding contrast.
The difference between the two brushes is the size of the grid that it employs. The Custom Filter III brush uses a 3x3 grid while Custom Filter V uses a 5x5 grid. A thorough explanation of convolving algorithms, along with sample grids can be found at http://www.ZBrushCentral.com.
Modifiers:
Intensity: Amount of effect. Range = -100 to +100. Default = 1.
AutoScale: Adjusts the value of all grid values so that their combined effect equals the value of the intensity slider. Default = On
Additive: When highlighted causes this filter’s combined effect to be added to the center pixol’s intensity value. When un-highlighted, this filter’s combined effect is blended with the center pixol. Default = Off.
