Chapter 8
Polypainting and SpotLight
Polypainting refers to the process of applying color values directly to the polygons of a mesh using the sculpting brushes. It’s very much like painting a real 3D object: You can blend and mix colors on the surface of your model to create the look of realistic skin, details on hard surfaces, even decals and logos. You can take advantage of many of the advanced brush features to design your own special polypainting brush presets that suit your own style of working.
ZBrush 4 introduces SpotLight, an advanced image editing program built into the ZBrush interface that allows you to edit images and then project the colors of those images onto the surface of the model. SpotLight’s unique interface makes this process very easy and fast, which saves you the need to leave ZBrush and edit your image files in another program.
This chapter introduces polypainting techniques and gives you a tour of SpotLight with practical examples that will tell you how to do the following:
- Paint colors on a surface
- Use cavity and occlusion masking
- Edit images in SpotLight
- Save SpotLight files
- Project colors from SpotLight images onto a surface
The technical aspects of polypainting sound complex at first, but in reality it’s quite simple. Using polypainting, you apply RGB values (red, green, and blue) to each vertex of a model. The color values are blended across the face of the polygons that share those vertices, creating what appears to be very smooth and detailed coloring. Figure 8-1 illustrates this point.
Figure 8-1: Color values are applied to each vertex and then blended across the polygon face.
Polypainting is performed using the same sculpting brushes you’ve been using throughout this book. Your polypainting will look better on a surface that has a lot of polygons, so usually you want to polypaint your 3D tools when they are set to their highest subdivision.
To polypaint a 3D tool, it must be on the canvas, in Edit mode, and the Colorize button in the Tool palette must be activated. The sculpting brushes you use to paint the surface need to have Rgb mode activated. You can actually have Rgb mode and Zadd on together, which means the brush can be used to paint and sculpt at the same time, but most artists prefer to polypaint their models after they have been sculpted.
The exercises in the following section demonstrate a typical workflow for polypainting a 3D tool.
Polypainting Basics
Let’s take a look at some of the general concepts behind polypainting. In this exercise you’ll see how to polypaint on a basic PolySphere and how the resolution of the mesh affects the quality of the brushstrokes painted on the surface.
1. Open a new ZBrush session.
2. Open Light Box to the Tool section and double-click the PolySphere.ZTL tool.
3. Draw it on the canvas and switch to Edit mode.
4. Press Ctrl+D three times to subdivide the model three times. The PolySphere already has three levels of subdivision, so this gives the PolySphere a total of six subdivision levels. At SDiv 6, the surface has 1.572 million polygons.
5. Open the materials fly-out library and select the SkinShade4 material (see Figure 8-2). This material is completely white, so the appearance of color values applied to the surface will accurately reflect their color values.
Some materials, such as the MatCap Red Wax material, have a color component to them. If you paint color on surfaces that use a colored material, the colors you paint on the surface will combine with the color of the material and look “off.” Materials are discussed in Chapter 9, “Rendering, Lighting, and Materials.”
Figure 8-2: Select the SkinShade4 material.
6. Use the Save As button in the File palette to save the project as PolyPaintTest.ZPR. Save the project in the ZBrush 4.0Projects folder in which the project appears in Light Box. In Windows, this folder is found in Program FilesPixologic. On a Mac, the folder is found in the Applications folder.
Now let’s take a look at how to activate polypainting. This is a simple but important step and understanding it will explain some mysteries about ZBrush.
7. On the left shelf, drag the mouse pointer within the color picker and select the blue color (see Figure 8-3). The PolySphere turns blue when you do this. As you continue to select colors in the color picker the color on the surface changes.
Figure 8-3: Use the color picker to select a blue color. This causes the entire PolySphere to turn blue.
Figure 8-4: Turn on Colorize in the PolyPaint subpalette of the Tool palette.
8. Open the Tool palette and scroll down until you see the Polypaint subpalette. Expand this subpalette and press the Colorize button (see Figure 8-4). When you do this, the PolySphere turns white.
9. Make sure the Standard brush is the currently selected brushstroke. On the top shelf, turn off the Zadd button and turn on the Rgb button. Make sure Rgb Intensity is set to 100 (see Figure 8-5).
Figure 8-5: On the top shelf, turn on Rgb and set Rgb Intensity to 100. Turn off Zadd.
10. Drag on the surface of the model. The brush leaves a blue stroke (see Figure 8-6).
11. In the color picker, select a red color and drag on the PolySphere again. Now the brush leaves a red stroke.
So what just happened here? When the Colorize button is off, the color of the surface changes each time you pick a new color using the color picker. Once you turn on the Colorize button, you have activated polypainting for the surface. Now the surface turns white and you can use the Sculpting brushes to apply the current color picker value to the surface of the model. If you turn Colorize off, the strokes you painted disappear and the model goes back to a solid color. Turn Colorize back on and the colored lines reappear.
The color values of the strokes you paint on the surface are stored within each vertex, so they won’t be erased if you turn off the Colorize button; you just won’t be able to see the strokes until you turn Colorize back on. When you save your model to disk as a Ztool (ZTL) or as a Zproject (ZPR), the polypaint information is saved as well.
Masked areas of the surface will be protected from colors painted on the surface.
12. Continue on to the next section using the same PolySphere.
Figure 8-6: Drag on the surface to create a blue colored stroke.
Activating Polypaint
The Colorize button in the Polypaint subpalette of the Tool palette enables polypainting on the surface. Constantly going back to this button to turn on polypainting can get tiring. There are two other ways to enable polypainting:
1. Turn on the paintbrush icon for the SubTool you want to polypaint in the SubTool subpalette of the Tool palette.
2. Brush on the surface of the model with any sculpting brush that has the Rgb button activated. This will enable polypainting even if the Rgb Intensity slider is set to 0. You may have to rotate the view of the surface to get the display to update properly after brushing on the surface.
Secondary Color
So what happens if you do want to erase the colored strokes on the surface? Below the color picker you’ll see two color swatches. These swatches are a way to store a backup secondary color so you can erase strokes or just have a second color stored in memory for use when you need it (see Figure 8-7).
Figure 8-7: The color swatches below the color picker store a main and secondary color.
To erase the strokes you’ve painted on the surface, you can set the secondary color to white and then paint over the strokes. Here’s how this works:
1. Below the Color palette, click the swatch on the left. This activates the secondary color selection.
2. Choose a white color by moving the picker to the upper-left corner of the center square within the color picker.
The swatch on the left becomes white.
3. Press the SwitchColor button below the swatches (hotkey = V). The colors in the two swatches are swapped, so now the main color is white and the secondary color is whatever the main color was.
4. Paint over the red and blue strokes you painted in the previous section.
The white color of the brush is painted on top of the colored strokes, essentially erasing them from the surface (see Figure 8-8).
Now let’s try something a little more interesting.
5. Press the Gradient button below the color picker.
6. Select a red color for the secondary color.
7. Paint some strokes on the surface.
When the Gradient button is on, the main and secondary colors are blended together. When you paint on the surface, the main color is at the center of the brushstroke and the secondary color is at the edges. This produces something like a watercolor effect (see Figure 8-9).
Figure 8-8: Paint white on top of other paint strokes to erase them.
Figure 8-9: Activate Gradient to blend the main and secondary color with each brushstroke.
8. Select a yellow color from the color picker and paint some more strokes to get an idea of how this works.
9. Press the SwitchColor button again to swap the main and secondary colors. Paint some more strokes.
10. From the alpha fly-out library, select alpha 34. Paint some brushstrokes.
When an alpha is applied to the brushstroke, the gradient feature can be used to create some interesting color effects (see Figure 8-10).
11. Continue on to the next section using the same PolySphere.
Figure 8-10: Apply an alpha texture to the brush and turn on Gradient to get some interesting effects in the brushstroke.
Color Blending
You can blend colors together by adjusting the Rgb Intensity slider on the top shelf.
1. In the color picker, select a dark blue color for the main color.
2. Turn off the Gradient button below the color picker. Choose Alpha Off from the alpha fly-out library on the left shelf to turn the alpha off.
3. Set the Rgb Intensity slider to 15. Paint some strokes on the surface.
The blue color of the stroke is faded. At 15, it is 15 percent of the intensity selected in the color picker (see Figure 8-11). This is similar to reducing the opacity of a paintbrush when using a paint program such as Photoshop.
Figure 8-11: Lower the Rgb Intensity slider on the top shelf to reduce the intensity of the color painted on the surface.
4. Paint repeated strokes over the same area to build up the color.
As you paint repeatedly over the same strokes, the color of each new stroke is blended with the stroke below it.
5. Choose a red color and paint on top of the blue strokes.
Figure 8-12: Click the RGB Intensity button in the Tablet Pressure subpalette of the Brush palette to adjust how the pen pressure affects the intensity of the color.
When you paint red over blue, the colors are mixed together, resulting in a purple color.
If you’re using a digital tablet, you’ll notice that the color intensity is pressure sensitive, so the harder you press, the more the intense the color becomes. You can build up color slowly by repeatedly brushing lightly over area of the surface. You can also change the way in which pressure affects color intensity by editing the RGB Intensity edit curve in the Tablet Pressure subpalette of the Brush palette (see Figure 8-12). Expand the RGB Intensity edit curve in the Tablet Pressure subpalette to access the curve. Editing tablet pressure settings is covered in detail in Chapter 7, “Advanced Brush Techniques.” These settings may be different depending on which brush preset you choose from the sculpting brush fly-out library.
6. Continue to the next section using the same PolySphere.
Custom Polypainting Brushes
Many of the brush settings discussed in Chapter 7 can be adjusted to affect how a sculpting brush applies color to a surface. Tablet Pressure settings, Orientation, LazyMouse, BackTrack, and other features can be customized to create a wide range of polypainting effects. You can quickly create your own library of special polypainting brushes by customizing the brush settings and then saving the presets. Save them to the ZBrushes folder within the ZBrush 4.0 folder so that they appear in Light Box. It’s a good idea to give the brushes all the same prefix so that you can easily find them using the search feature in Light Box.
Blur Strokes
The Smooth brush can be used to blur the edges of a colored stroke painted on the model surface.
Figure 8-13: Use the Smooth brush to blur the strokes painted on the surface.
1. From the alpha fly-out library on the left shelf, select alpha 28. This is a simple white square.
2. Choose a red color and paint some strokes on the surface of the PolySphere.
3. Hold the Shift key and turn off the Zadd button on the top shelf. Make sure Rgb is on and Rgb Intensity is set to 100. By making these adjustments while holding the Shift key, you’re setting the properties of the Smooth brush.
4. Hold the Shift key and paint over the strokes on the surface of the PolySphere. This blurs the edges of the strokes (see Figure 8-13).
You can adjust the intensity of the Smooth brush’s blurring effect by lowering the Rgb Intensity slider while holding the Shift key.
Fill an Object with Color
At this point your PolySphere probably looks like a mess. How do you clear the entire surface? You can do this by filling the entire object with a single color.
1. Set the color picker to white if it’s not already.
2. Set Rgb Intensity to 100.
3. Open the Color palette and click the FillObject button (see Figure 8-14). The entire PolySphere turns white.
Figure 8-14: The Fill Object button fills the entire surface with the current color.
This button is like a paint bucket that covers the whole object with the color currently selected in the color picker. You can use the Fill Object button as a way to tint the surface as well.
4. Select a bright red color in the color picker.
5. Paint some strokes on the surface of the PolySphere.
6. Set Rgb Intensity to 10.
7. Select a dark blue color in the color picker.
8. Open the Color palette and click the FillObject button.
The PolySphere is tinted slightly blue. This is because the Rgb Intensity setting determines the intensity of the color applied to the surface when you use the FillObject button. Each time you press the button, the object is filled at an intensity of 10, so you can press it repeatedly to gradually increase the amount of blue applied to the surface (see Figure 8-15).
Figure 8-15: When Rgb Intensity is set to a low value, each time you press the FillObject button, the surface is tinted with the current color.
Masked areas of the surface will be protected from the colors applied to the surface when the Fill Object button is used. The FillLayer button will clear the canvas and fill it with the current color.
Use Brush Texture
You can apply a 2D texture to the surface of a model using the sculpting brushes. The texture will override the color set in the color picker so that with each brush stroke, the colors in the texture are applied to the surface. Here is a quick demonstration:
1. Clear the PolySphere using the Fill Object button or load the PolyPaintTest.ZPR project you created earlier in this chapter. A version of this project is found in the Chapter 8 folder on the DVD.
2. Make sure the Standard brush is the current sculpting brush preset. On the top shelf, Zadd should be off and Rgb Intensity should be set to 100.
3. From the texture fly-out library on the left shelf, choose Texture 12. This is the orange and yellow star (see Figure 8-16).
Figure 8-16: Choose the star texture from the Texture fly-out library.
4. Open the stroke type fly-out library on the left shelf and select the DragRect stroke type.
5. Drag on the surface of the PolySphere. The star appears on the surface.
6. Release the brush and drag again. Each time you drag on the surface, a new star appears on top of the previous stroke (see Figure 8-17).
7. Experiment painting on the surface using other stroke types such as Spray, FreeHand, and DragDot.
8. Lower the Rgb Intensity slider on the top shelf to decrease the opacity of the texture.
Figure 8-17: The star texture appears on the surface of the PolySphere when it is applied to the Standard brush. Use the FreeHand stroke type to create patterns with the texture.
Fill with Texture
If you use the FillObject button in the Color palette while there is a texture selected in the texture fly-out library, the texture will be applied to the unmasked portions of the 3D tool.
Polypainting and Subdivisions
As you learned earlier in this chapter, the quality of the strokes painted on the surface is directly related to the number of vertices in the mesh. The more vertices you have, the smoother the edges will appear in the strokes painted on the surface. This is why it is often best to polypaint your models at the highest possible subdivision level.
This exercise demonstrates this principle.
1. Load the PolyPaintTest.ZPR project you created earlier in this chapter. A version of this project is found in the Chapter 8 folder on the DVD.
2. Open the Geometry subpalette of the Tool palette and set the SDiv slider to 1. You can also press Shift+D repeatedly until the model is at its lowest subdivision level.
3. Select a red color from the color picker and paint a stroke on the surface.
The edges of the stroke are very blocky because at SDiv level 1, there aren’t very many vertices in the surface.
4. Open the Geometry subpalette of the Tool palette and set the SDiv slider to 6. You can also press D repeatedly until the model is at its lowest subdivision level.
Notice that even though the surface is increasing in subdivisions, the edges of the brush stroke look very blocky (see Figure 8-18). This is why you’ll get the best results if you paint a surface at the highest subdivision level.
Figure 8-18: Paint strokes applied to a surface at a low subdivision level will appear blocky even when the surface is set to a high subdivision level.
Now that you have a basic understanding of how polypainting works, let’s take a look at some techniques for painting a model. There are as many approaches to polypainting as there are ZBrush artists, so there’s no one way to do it. Generally speaking, I like to use techniques that are similar to those used by effects artists who paint actual models. I use brushes that emulate the behavior of air brushes. I like to apply several coats of color at a low Rgb intensity. The following sections demonstrate some of the techniques I prefer to use. As you become more comfortable painting your models, no doubt you will develop your own approach.
The images in this chapter are black and white, so obviously it will be difficult to see exactly how the colors look on the model. For this reason, I have recorded a color movie based on this demonstration. The movies file is named polyPaintDragon.mov and is found in the Movies folder on the book’s DVD.
Tips on Polypainting
Here are just a few helpful tips you can use when polypainting an object:
- If you use the Spray stroke type to paint colors on the surface, the value (or brightness) of each dot in the stroke will be varied randomly. You can increase the amount of randomness by setting the Color slider in the Stroke palette to 1. To turn this feature off, set this slider to 0. You can also find this slider in the stroke type fly-out library.
- The Color Spray stroke type varies the hue of each dot in the stroke randomly. Again, to change the behavior of this feature, adjust the Color slider in the Stroke palette.
- To select a color from the surface, hold the mouse pointer over the color you want to pick and press the C hotkey. You can also do this by dragging from the color picker to the color you want to select. The selected color value will not include the colors of preview shadows or the color of the material.
- If you want to select the color as it appears exactly on the canvas (that is, the color of the surface, shadows, and material), hold the Alt key and drag from the color picker to the color you want to select.
- You can convert the colors painted on the surface into a mask using the Mask By Intensity, Mask By Hue, or Mask By Saturation button in the Masking subpalette of the Tool palette. Each button creates a mask from the colors in a slightly different way (that is, based on the intensity, hue, or saturation of the colors painted on the surface).
- You can convert the colors painted on the surface into polygroups by pressing the From PolyGroup button in the Polygroups subpalette of the Tool palette.
- The FillObject button will fill only the visible or unmasked parts of the surface on the model. Hide or mask parts of the object you don’t want colored.
- Colorize can be activated per subtool. The SubTool Master ZPlugin (discussed in Chapter 4) has a button for filling all the visible SubTools at once with a color.
- Colorize is automatically activated for a surface when you paint on it with a brush that has Rgb activated on the top shelf. This is true even if Rgb Intensity is set to 0.
- You can use layers to create and blend different polypaint layers together on the same surface. This technique is discussed in Chapter 10, “Morph Targets, Layers, and the ZBrush Timeline.”
Create a Base Coat
You can start painting a model at any point during the sculpting process; however, many artists prefer to paint the surface after they have done most of their sculpting and detailing. In this example, you’ll start with a dragon head I created. Of course, you’re also welcome to use this approach on your own model (see Figure 8-19).
Figure 8-19: The dragon head model that will be used in this section can be found in the Chapter 8 folder on the DVD.
As mentioned earlier in the chapter, you’ll get the best results if you paint the model at the highest possible subdivision level. The model I’m using has five subdivision levels. At SDiv 5, the model uses 3.2 million polygons. Normally I would subdivide the model one more time for a total of six levels of subdivision. The model would be around 12 million polygons at SDiv 6; however, I want to make sure the example model can be easily used by readers using laptops or less-powerful machines.
1. Use the Open button in the File palette to load the PolyPaintDragon_v01.ZPR project from the Chapter 8 folder on the DVD.
2. Open the Geometry subpalette of the Tool palette and make sure the model is set to the highest subdivision level; this should be SDiv 5.
3. Make sure the SkinShade4 material is selected in the materials fly-out library.
I’ve decided that this dragon will be mostly reddish in color. So I’ll start by experimenting with a color for the base coat.
4. Drag the cursor in the outer square of the color picker to the upper-left corner to select a red hue. Drag the cursor to the center square toward the middle to select a color that is not too dark or saturated (see Figure 8-20).
Figure 8-20: Use the color picker to choose a reddish color.
5. The color on the model should update as you move within the color selector. If the color is not updating, open the Polypaint subpalette of the Tool palette and make sure the Colorize button is off.
Figure 8-21: When you fill an object with color the Colorize button is automatically turned on, as is the paintbrush icon in the subtool subpalette of the Tool palette.
6. Once you have selected a suitable color for the base coat, make sure Rgb Intensity is set to 100, open the Color palette, and press the FillObject button.
The dragon won’t look any different when you fill it with the color, but the color has now been applied to the entire surface. Note that Colorize is automatically activated when you fill the object, so the model is all ready for polypainting. This is also indicated by the paintbrush icon, which is activated for the dragon’s head in the subtool subpalette of the Tool palette. The Colorize button in the Polypaint subpalette and the paintbrush icon in the subtool subpalette share the same function: They both activate polypainting for the model (see Figure 8-21).
7. Choose a white color in the color picker. Note that the teeth, eyes, and other subtools on the head all turn white while the head remains red (see Figure 8-22). This is because Colorize has not been activated for these subtools, just the head. If you turn off the Colorize button, the head will turn white again. Turn it back on and the head returns to red.
8. Use the Save As button in the File menu to save the project as PolyPaintDragon_v02.ZPR.
Figure 8-22: The head is colored red while the teeth, eyes, and other subtools are white.
Create Color Zones
Now that you have a solid color chosen for the base coat, you can start painting color zones on the head. Color zones are areas of color painted on different areas of the head. By dividing the head into areas of color, you can suggest something about the anatomy beneath the skin or scales of your character or creature. Areas of the head that have more blood vessels may have more red and purple hues. Areas close to bone may have more yellow or white. This is true of humans as well as many other types of animals. Of course, when you’re painting a fantasy creature, you have much more liberty in terms of the colors that you use or the placement of color zones. When you divide up the head into regions of colors, your model will look less like it has been simply covered with a coat of paint.
Color zones are often painted using very vibrant colors. It’s okay to go a little over the top. Keep in mind that these color zones will be covered up with successive coats of color later on in the painting process, so even though they look exaggerated when you first paint them, they will be much more subtle in the final version.
1. Let’s start by painting deep red and purple around the area of the eyes. In the color picker, select a deep dark purple.
2. Press the SwitchColor button below the color picker so that the purple becomes the secondary color.
3. Use the color picker to choose a deep dark red. This will become the main color.
4. Click on both color swatches so that you can see a slight shadow at the top of the swatch. This indicates that both the main and secondary colors are active. Press the Gradient button to activate the gradient feature (see Figure 8-23).
Figure 8-23: Click on each color swatch so that a shadow appears at the top of both swatches. Turn on the Gradient button.
5. Choose the Standard brush in the sculpting brush fly-out library. Make sure the Zadd button is off on the top shelf. The Rgb button should be on. Set Rgb Intensity to 10.
6. Set the stroke type to Spray. In the Stroke Type Library, set the Color slider to 0.1. This reduces the randomization of the color values used by the Spray stroke type.
7. In the alpha fly-out library, choose alpha 58. This has a series of scribble vertical lines (see Figure 8-24).
8. Use the Save button in the Brush palette to save the brush as PolyPaintSpray.ZBP. Save the brush to the ZBrush 4.0Brushes folder so that you can easily find it in the Brush section of Light Box later on (see Figure 8-25).
9. Make sure that symmetry is active across the x-axis in the Transform palette.
10. Set the draw size to 25. Zoom in on the area of the eye and start painting strokes in this area. You don’t have to be particularly neat about it; in fact, the more varied your stroke, the better it will look in the end.
11. On the right shelf, press the Solo button to hide the eyes and other subtools. Paint inside the eye socket (see Figure 8-26).
Figure 8-24: Choose alpha 58 in the alpha fly-out library.
12. As you paint, make sure to vary the colors applied to the surface. You can do this by switching the main and secondary colors (hotkey = V). You can also sample the colors you’ve painted on the surface by holding the C key while holding the mouse pointer over the surface. This is a great way to blend colors across the surface.
13. Add additional color zones. Paint bluish colors along the lips; paint deep reds around the nostrils; pale pinks, yellows, and reds on the larger scales, horns and bony parts. Paint dark reds in the larger folds of flesh.
Figure 8-25: Save the brush preset so that you can use it for future ZBrush sessions.
Neatness does not count. Go ahead and be very loose with your strokes. The end result should look almost like a clown. Experiment with using different alphas and other settings while you work. Figure 8-27 shows the model using the Flat color material after the color zones have been painted. To see the image in color, watch the PolyPaintDragon.mov movie in the Movies folder of the DVD.
Figure 8-26: Paint purple and red in the eye sockets and around the area of the eyes.
Figure 8-27: Color zones have been painted on the surface of the model.
14. While working, you should occasionally select the Flat color material from the material fly-out library so that you can see exactly how the colors are applied to the surface without the influence of lights or shadows.
15. Use the Save As button in the File menu to save the project as PolypaintDragon_v03.ZPR.
Paint a Mottling Pass
Once you have the colors of the head segregated into zones, you’ll need to break up the color using what’s known as a mottling pass. This technique is taken directly from artists who have been painting masks and maquettes in the movie industry for years. It was introduced to me by Scott Spencer, and even though it may seem like an odd approach at first, it always seems to look great in the final process. Check out Scott’s book ZBrush Creature Creation (Sybex, 2011).
To create a mottling pass, you’ll paint white squiggly lines all over the surface. These lines breaks up the color zones, making the face look less clownlike. In the end, it will also look as though the skin and scales are made up of layers of organic material.
1. Continue with the dragon model from the previous section or load the PolypaintDragon_v03.ZPR project from the Chapter 8 folder on the DVD.
2. Select the Standard brush from the sculpting brush library. Set the stroke type to DragRect.
3. From the alpha fly-out library, select alpha 22 (see Figure 8-28). This is a series of squiggly lines.
Figure 8-28: Choose alpha 22 from the alpha fly-out library.
4. In the color picker, set the main color to white.
5. Set Rgb Intensity to 20. Make sure the Rgb button on the top shelf is on and the Zadd button is off. Turn off the Gradient button below the color picker.
6. Use the Save button in the Brush palette to save the brush as PolyPaintMottle.ZBP. Save the brush to the ZBrush 4.0Brushes folder so that you can easily find it in the Brush section of Light Box later on.
7. Drag on the surface to add the stroke. The pattern will appear larger if you continue to drag before releasing. Rotate the pattern by dragging left or right before releasing (see top image in Figure 8-29).
8. Drag repeatedly over the surface to create a pattern with overlapping strokes (see bottom image in Figure 8-29).
9. Continue to cover the entire surface of the head. Create smaller strokes near the lips and eyes, larger strokes over the scales.
You don’t need to completely obscure the colors of the underlying layers, just use the mottling pass to break up the color zones. Once the surface is covered, you’ll paint a light reddish color over the surface to tie the colors together. You may want to turn off symmetry when creating the pattern along the center of the model. Figure 8-30 shows the result using the Flat color material.
10. Select the Standard brush from the sculpting brush library. Set the stroke type to Color Spray.
11. Turn off the Zadd button and turn on Rgb. Set Rgb Intensity to 5.
12. Choose a light red color from the color picker.
13. From the alpha library, choose alpha 23 (see Figure 8-31).
Figure 8-29: Create overlapping patterns using the PolyPaintMottle brush to break up the colors of the model.
Figure 8-30: The strokes created with the PolyPaintMottle brush break up the colors on the surface.
Figure 8-31: Choose alpha 23 from the alpha fly-out library.
14. Use the Save button in the Brush palette to save the brush as PolyPaintDust.ZBP. Save the brush to the ZBrush 4.0Brushes folder so that you can easily find it in the Brush section of Light Box later on.
15. Set Draw Size to 30. Use the brush to paint lightly over the surface (see Figure 8-32). Again, you don’t want to completely obscure the colors of the previous passes. The light red color is meant to make the color zones and the mottling pass seem more cohesive.
16. Continue with this file in the next section.
Figure 8-32: Paint over the surface with a light red color.
Paint Subsurface Details
Blood vessels and scar tissue are good examples of subsurface details. They appear just below the skin, which gives the impression that the surface is made up of overlapping layers of organic material. This particular dragon is covered in a lot of different-size scales, so it’s unlikely that you would see as many subsurface details as you would on other models, such as an old man. Even so, many faint blood vessels can be added to the base of the larger scales. Blood vessels close to the surface of a creature expose the blood to air, which helps to keep him cool. In addition, you can imagine that the dragon may have scars from ancient battles. The tissue near the old scars may appear dark just below the skin.
In this section, you’ll add these details to the dragon.
1. To paint veins on the surface, you can use the detailBrush you created in Chapter 7. If you have not created this brush, you can use the Load button in the Brush palette to load the preset from the Chapter 7 folder on the DVD.
2. On the top shelf, set ZIntensity to 5 and Rgb Intensity to 20. Set Draw Size to 10.
3. Select a dark blue purple color palette. Turn off the Activate Symmetry button in the Transform palette.
4. Open the Stroke palette and turn LazyMouse off.
5. Use the Save button in the Brush palette to save the brush as PolyPaintVein.ZBP. Save the brush to the ZBrush 4.0Brushes folder so that you can easily find it in the Brush section of Light Box later on.
Figure 8-33: Veins and dark splotches are painted on the surface.
This brush is designed to use tablet pressure. As you paint on the surface, vary the pressure. Increase the pressure to make the stroke appear thin or dark and raise the surface.
6. Use the brush to create squiggly lines near the base of the larger scales and in the areas near the eyes and other parts of the head where you might imagine blood vessels would be visible.
7. Choose the PolyPaintSpray brush to paint dark reds, blues, and purples. Create dark splotches on the surface. Figure 8-33 shows the model with the flat color material applied.
8. Use the Save As button in the File menu to save the project as PolyPaintDragon_v04.ZPR. Continue with this project in the next section.
Use Cavity Masking
You can increase the detail on the surface and make the scales more apparent using cavity masking. When you create a cavity mask, the recessed areas of the surface are protected from changes. You can invert the mask and fill the recessed areas with a darker color. This will make the spaces between the scales and other areas appear darker.
1. Open the Masking subpalette of the Tool palette.
2. Below the Mask By Cavity button, set the Intensity slider to 50 (see Figure 8-34). This slider determines the intensity of the cavity mask. You need to set this value before creating the mask.
Figure 8-34: Set Intensity to 50 in the Masking subpalette of the Tool palette.
3. Press the Mask By Cavity button. After a few seconds you’ll see a mask appear on the surface. The mask appears in the recessed areas of the surface (top image in Figure 8-35).
4. Press Ctrl+I to invert the mask. You can also Ctrl+click on a blank part of the canvas to invert the mask (bottom image in Figure 8-35).
Figure 8-35: Cavity masking creates a mask in the dark recesses of the surface (top image). The mask is inverted (bottom image).
5. Use the color picker to choose a dark red color. On the top shelf, set Rgb Intensity to 5.
6. In the Masking subpalette of the Tool palette, turn off the ViewMask button. This will make it easier to see how the color is applied.
7. In the Color palette, press the Fill Object button. The dark red color will be applied to the recesses of the surface. No doubt it may be hard to see much of a difference since the Rgb Intensity setting is very low. Press the button repeatedly and you’ll start to see the dark red color between the scales. Figure 8-36 shows how the color looks when the Flat material is applied to the model.
Figure 8-36: The unmasked parts of the dragon are filled with a dark red color
8. Once you’re satisfied with the color, Ctrl+drag on a blank part of the canvas to remove the mask.
9. Use the Save button in the File palette to save the project as PolyPaintDragon_v05.ZPR.
Use Ambient Occlusion Masking
Ambient Occlusion is a type of shadowing that occurs when light rays are unable to reach the cracks and crevices of a surface. This kind of shadowing is most apparent on overcast days or in a room that is illuminated with diffused light. ZBrush can create a special type of mask in the recessed areas of a surface that simulates this type of shadowing. The mask is much softer and broader than masks created using cavity masking.
In this exercise, you’ll create an ambient occlusion mask, invert the mask, and then paint dark colors into the unmasked areas. This will create darker areas in the folds of flesh and in the cracks between the larger scales.
Tips on Using Cavity Masks
Cavity masking is a very powerful feature that can be applied to a wide variety of sculpting and polypainting techniques. Here are some tips on using the cavity mask controls in the Masking subpalette of the Tool palette:
- The Blur slider to the right of the Mask By Cavity button applies blurring to the cavity mask when it is generated. This can help reduce jagged edges in the mask.
- You can blur the cavity mask after you create it by Ctrl+clicking on the mask.
- Hold the Shift key to access the controls for the Smooth brush. While holding the Shift key, turn off the Zadd button. Set Rgb Intensity to 10. Hold the Shift key and paint on the surface to blur out any jagged areas left by the cavity mask.
- To fine-tune the way the cavity mask is applied, expand the Cavity Profile edit curve in the Masking subpalette of the Tool palette.
- Cavity masking can be applied to the brush rather than the surface. Use the CavityMask options in the Auto Masking subpalette of the Brush palette. When you apply cavity masking to a brush, the mask is updated with each stroke.
Ambient occlusion masks tend to be fairly faint and hard to see. You can turn off polypainting and use the flat material to make the mask easier to see.
1. Continue with the project from the previous section or load the PolyPaintDragon_v05.ZPR file from the Chapter 8 folder on the DVD.
2. Use the color picker to set the main color to white.
3. From the materials fly-out library, select the Flat Color material.
4. In the Polypaint subpalette of the Tool palette, turn off Colorize. The dragon will appear solid white. Don’t worry; you haven’t lost any of the colors painted on the surface.
5. Expand the Masking subpalette of the Tool palette. Under the Mask Ambient Occlusion button, set Occlusion Intensity to 1.3.
6. Set AO Scan distance to 0.35. This sets the maximum distance ZBrush will use when creating the mask. Higher values mean that more of the surface will be masked but it will also take longer to calculate (see Figure 8-37).
Figure 8-37: Adjust the settings for Ambient Occlusion masking before creating the mask.
7. Leave the AO Aperture at the default setting of 90. Lowering this value will diminish the size of the ambient occlusion mask.
8. Calculating an ambient occlusion mask on a complex surface that has a lot of polygons can take a long time. It’s usually a good idea to save your work before creating the mask. Use the Save As button in the File palette to save the project as PolyPaintDragon_v06.ZPR.
Figure 8-38: The progress bar at the top of the interface indicates the time it will take to calculate the ambient occlusion mask.
9. Press the Mask Ambient Occlusion button. This takes a few minutes. The countdown will appear at the top of the ZBrush interface along with a progress bar (Figure 8-38). This is a good time to take a break!
Once the mask has been calculated, the dragon should look something like Figure 8-39.
Figure 8-39: The ambient occlusion mask has been applied to the dragon head.
10. Press Ctrl+I or Ctrl+click on a blank part of the canvas to invert the mask.
11. In the Masking palette, turn off the View Mask button.
12. In the Polypaint subpalette of the Tool palette, turn on the Colorize button. The colors will appear on the surface.
13. Set Rgb Intensity to 14. Use the color picker to choose a dark purple color. In the Color palette, click on the FillObject button to fill in the unmasked areas. Press the button repeatedly until you’re satisfied with the strength of the dark color applied to the surface (see Figure 8-40).
14. Hold the Ctrl key and drag on a blank part of the canvas to clear the mask.
15. Save the file as PolyPaintDragon_v06.ZPR.
Paint Surface Details
The colors for the dragon are meant to serve as a foundation. For the final pass, you’ll paint the surface details. By building a foundation of color through successive passes, you’ll ensure that the final model looks interesting, has variation, and seems believable.
Figure 8-40: Fill the unmasked areas with a purple color.
The details on the surface can be as elaborate as you like. I recommend doing an image search for snake and lizard scales. Take a look at what kinds of patterns appear on the scales of venomous snakes. How do they differ from nonvenomous snakes? Look at dinosaurs and birds for inspiration as well. Also check out the work of other fantasy artists, such as John Howe. The Dracopedia by William O’Connor (Impact Books, 2009) is a book I find particularly entertaining and inspiring.
Figure 8-41: Images of snake and lizard scales can be used as reference.
I’ve included several photographs from my own reference library. These are images I took of various snakes and lizards at the Desert Museum in Arizona. Color versions of these images are found in the Chapter 8 folder of the DVD. Note the color variations on each individual scale as well as the repeating patterns in the overall surface of the animals.
Generally speaking, the techniques for creating surface detail are not that different from the techniques used to paint the underlying layers. In my version of the dragon, I painted the large scales on the top of the head using the Standard brush with an Rgb Intensity of 25. I painted dark red strokes to create simple designs on the scales based on the color of the scales in the upper-left image in Figure 8-41. I applied alpha 08 from the alpha fly-out library to the brush and varied the colors as I painted the strokes. Figure 8-42 shows the result. The Flat Color material is applied to the surface to make the strokes more apparent.
Figure 8-42: Dark red and brown brushstrokes are added to the large scales on the head.
For the smaller scales of the neck, I used the upper-right image in Figure 8-41 as inspiration. I lightly painted individual scales, alternating light and dark colors to create a pattern (see Figure 8-43).
Figure 8-43: A pattern is created on the smaller scales of the neck by alternating light and dark colors on each scale.
For the lips, I painted dark colors using repeating thin lines. I painted light, reddish colors on the inside edge of the eyelids as well. You can continue to work over the surface adding color details where needed. It’s never finished until you feel that it’s finished. The important thing to keep in mind is that if you take the time to build up layers of colors for the undercoat, the details you paint on the surface will look much more organic and interesting.
When you feel that you have done enough, save the file as PolyPaintDragon_v07.zpr. A version of this project can be found on the Chapter 8 folder of the DVD. Figure 8-44 shows the final version. A color version of this image can be found in the color insert section of this book.
Use Color to Create a Story
The colors you paint on the surface can create a sense of story for your dragon. Does your dragon have elaborate markings? Battle scars? Do the colors indicate danger? Attract mates? Do dragons have tattoos? Do the markings indicate rank? Age? Class? Number of slain knights or burned villages? You can have a lot of fun thinking up the history behind the colors of your dragon.
Figure 8-44: The final version of the dragon.
SpotLight is one of the most exciting new additions to the ZBrush toolset. The creative potential of this innovative image editing and projection technology seems limitless. SpotLight is designed to give artists the ability to manipulate images within the ZBrush interface. This eliminates the need to leave the ZBrush environment to edit images in a second software package such as Photoshop. Using SpotLight, you can color correct, transform, smudge, smear, and layer digital images and then project the result directly on your model.
In the following sections, you’ll learn the basics of using SpotLight, starting with a tour of the interface. Later on in the chapter, you’ll use SpotLight to texture the hot rod model started in Chapter 5.
Open and Close SpotLight
SpotLight is used for editing textures, so to launch SpotLight, you’ll need to select a texture either from the texture library on the left shelf or from the Texture section of Light Box. A texture is simply an image file that’s loaded into ZBrush. ZBrush accepts the most common image formats, such as Photoshop (PSD), Pict (PCT), bitmap (BMP), Tif (TIF or TIFF), Jpeg (JPG or JPEG), and Gif (GIF).
The following sections show you two ways to launch SpotLight.
Launch SpotLight from the Texture Library
This exercise demonstrates how to add an image to SpotLight from the texture library.
1. Start a fresh session of ZBrush.
2. On the left shelf, open the texture fly-out library.
3. Click on a texture such as Texture 01 (see Figure 8-45).
The fly-out library closes when you select a texture. You’ll see the selected texture appear as an icon on the left shelf.
Figure 8-45: Choose Texture 01 from the texture fly-out library.
4. Click on the texture on the left shelf to open the fly-out library again. Click the Add To SpotLight (plus/minus) button in the lower-left portion of the fly-out library (see Figure 8-46).
Figure 8-46: Click the Add To SpotLight button in the texture fly-out library.
The texture now appears on the canvas in full size. You’ll also see a ring of small icons. This ring is the control interface for SpotLight. Note that the texture on the canvas appears slightly transparent (see Figure 8-47)
To remove the texture from SpotLight, just select it in the texture library and press the plus/minus button again.
5. To close SpotLight, press Shift+Z.
Figure 8-47: The texture appears on the canvas when it has been added to SpotLight. The SpotLight interface appears as a ring of icons on top of the image.
As long as images have been added to SpotLight you can turn it on and off again using the Shift+Z hotkey combination. The images you have added to SpotLight will remain as part of SpotLight unless you remove them or close and restart ZBrush. The Shift+Z hotkey combination turns off SpotLight so that you can work on models or other artwork in ZBrush. ZBrush still remembers which images have been loaded and their current status. Press Shift+Z again to turn on SpotLight at any time.
When you press Z without a modifier, the SpotLight interface (the ring of icons) is hidden. Press it again to display the interface. There are essentially two modes to SpotLight: Edit mode and Projection mode. You know you are in Edit mode when you see the interface dial (the ring of icons). In this mode, you can edit the SpotLight images. In Projection mode, the dial interface is hidden and the images you see on the canvas can be projected onto your models. In the following sections, you’ll learn how to work in these two modes.
Launch SpotLight from Light Box
Light Box is described in detail in Chapter 2. Recall that the icons in SpotLight are a preview of files saved to your local drive within the subfolders of the ZBrush 4.0 directory. Adding a texture from Light Box to SpotLight is very easy.
1. Click the Light Box button on the top shelf to open Light Box.
2. Click on the Texture heading in Light Box.
Figure 8-48: Select a texture from the Texture section of Light Box.
3. Click one of the textures to select it. A white border will appear around the texture indicating that is selected (see Figure 8-48).
4. Double-click the texture to launch SpotLight. In some cases you may need to double-click the image twice.
SpotLight will open and the image appears at full size. Note that any images you may have added to SpotLight will be scaled down and positioned at the bottom of the interface. (See Figure 8-49. The smaller image may be hidden by the Light Box interface. Close Light Box so that you can see the smaller image).
Figure 8-49: When a new texture is added to SpotLight, the other image appears scaled down at the bottom of the interface.
The last image you add to SpotLight always appears enlarged at the top of the interface, and previously added images appear at the bottom, scaled down. You’ll learn how to resize and reposition images later in this section. At this point, you’re simply building up a layout of active images. Imagine that you’re pulling images out of a box and placing them on a table. That’s basically what’s going on when you add images to SpotLight. You can add new images at any time while working in SpotLight.
Note that you can load multiple copies of the same image into SpotLight if you want to.
Load Images from the Internet into SpotLight
If you’re using ZBrush on Windows, you can also load images from the Internet directly into a SpotLight session without having to leave ZBrush. This feature is not available for Macintosh users.
1. Click the Light Box button on the top shelf to start Light Box.
2. Click the www heading to open the Internet search options.
3. Click the Yahoo icon.
4. In the search field, type in a search keyword such as “dragonfly.”
If your computer is connected to the Internet, after a few seconds SpotLight will fill up with images of dragonflies. The images you’re seeing are a result of doing an image search using the Yahoo search engine from within ZBrush!
At the top of each image you’ll see a small bar. The length of this bar gives you an indication of the file size. A longer bar indicates a larger file and a longer download time.
5. Double-click an image.
When you double-click an image, it is downloaded to your computer. The bar at the top of the image is filled with a white color indicating the progress of the download. Once the bar is completely white, the image has been successfully downloaded.
6. Once the image has downloaded, double-click it again and the image will be added to SpotLight.
Save and Load a SpotLight Session
Typically you’ll use several images within a single SpotLight session. For example, let’s say you’re working on dragon scales. You may end up with a number of images that have been added to SpotLight from various locations such as your hard drive, the Internet, and so on. You can save the SpotLight session as a file that can be loaded the next time you start ZBrush. This saves you the trouble of having to add the images all over again the next time you start ZBrush.
You can create separate SpotLight files for use in different ZBrush sessions. So you might have a SpotLight file dedicated to images of snake scales, another one dedicated to vehicle decals, and another one dedicated to eyeballs, and so on. A SpotLight file uses a special format that contains the image files and their status.
This exercise demonstrates how to save and load a SpotLight session.
Figure 8-50: Use the Save SpotLight button in the Texture palette to save the SpotLight file.
1. Make sure you have three to five images loaded into SpotLight and that the images are visible on the canvas.
2. Open the Texture palette and press the Save SpotLight button (see Figure 8-50). This will open up your computer’s file browser.
3. Save the file as SpotLightest.zsl. You’ll use this file for practice in the next few exercises.
4. To load a SpotLight file, use the Load SpotLight button in the Texture palette. You can have only one SpotLight file open at a time.
If you have been working in SpotLight, save your work before loading a different SpotLight file.
Transform Images
Now that you understand how to start SpotLight, let’s take a look at how you can do some actual work. The ring of icons that appears when you launch SpotLight functions as a menu and a manipulator at the same time. This exercise demonstrates how to move images around using the manipulator.
1. Continue with the SpotLight file from the previous section or use the Load SpotLight button in the Texture palette to load the SpotLightTest.ZSL file from the Chapter 8 folder on the DVD.
2. Click and drag on the largest image on the canvas.
The SpotLight menu pops over to the center of your brush cursor and the largest image moves as you drag on the canvas. This is how you move an individual image. Note that a red border appears around the image, indicating that it is selected.
3. Click and drag on one of the smaller images.
Each time you want to move an image around, just click and drag on it (see Figure 8-51).
4. Click and drag on a blank part of the canvas. Now all the images move together. This is a handy way to move everything aside if you need to make space on the canvas.
5. Double-click one of the smaller images.
This rearranges all of the images so that the small image now becomes enlarged and the other images are scaled down and aligned at the bottom of the screen.
Figure 8-51: Drag on an image to move it.
6. Click and drag in the center of SpotLight (within the small circle). This allows you to move the SpotLight interface without affecting the image.
7. Click the largest image again to place the interface on top of it. Click and drag the circular arrow icon at the top of SpotLight (see Figure 8-52).
Figure 8-52: Drag the circular arrow in the SpotLight interface to rotate the selected image.
This rotates the image. Drag this icon right or left to rotate the image clockwise or counterclockwise respectively. The SpotLight interface acts like a dial. Each of the menu icons around the ring of the interface is a switch. Select an icon such as the circular arrow at the top of the ring. Drag the menu left or right icon to rotate the dial and activate the selected function.
The pivot point for the center of the rotation is indicated by the circle at the center of the SpotLight interface. To change the pivot point, just click somewhere else in the image.
If you want the pivot point of rotation to be outside of the image, select the image by clicking it (the red border will indicate that the image is selected). Then drag the center of the SpotLight interface, reposition the interface outside of the mage, and then drag the rotation icon.
If you want to rotate all of the images in SpotLight at once, click outside the image to deselect it (the red border will disappear), drag the center of the dial to reposition the SpotLight interface, then drag the rotation icon at the top of the interface.
8. Click one of the smaller images to select it. Click and drag the box icon to the right of the rotate icon. This scales the image. Drag to the right to scale the image up; drag to the left to scale it down (see Figure 8-53).
Figure 8-53: Drag on the rectangular icon to scale the selected image.
The scale function is similar to the rotate function in that the scale pivot is based on the circle at the center of the interface. Just as with the rotate function, you can scale the selected image or deselect the image and scale all the images at the same time.
SpotLight Functions
Each icon on the SpotLight interface indicates a different function. The icons are grouped together based on their purpose. Some SpotLight functions are used to transform the images, like rotate and scale demonstrated in the previous section. Some of the functions are used to edit the image. Some of the functions affect how the image is projected onto a surface. This section gives a brief description of each function, going clockwise around the interface starting at the top. Many of these functions will be explored in more detail in the exercises of this chapter.
Rotate As demonstrated in the previous section, drag this icon left or right to rotate the selected image or all of the images together. The center of Light Box is the pivot point for rotation.
Scale As demonstrated in the previous section, drag on this icon left or right to scale the selected image or all of the images together. The center of Light Box is the pivot point for the scaling.
Pin This icon keeps the image at the center of the brush tip when you project the image onto a surface. Projection is discussed in the next section. Click this icon to toggle pinning on or off. When you see a white bar above the icon, this means that SpotLight is pinned. If pinning is off, the image will be projected onto the surface based on its current position on the canvas. When pinning is on, the area of the image at the center of the SpotLight image is pinned to the sculpting brush.
SpotLight Radius Drag left or right on this icon to set the SpotLight radius. This feature is used when projecting the image onto a surface. It allows you to see a small, transparent circular preview of the image while you project it on the surface.
Opacity This is used to dim the interface while you are projecting the SpotLight images onto a surface. It does not affect the opacity of the projected image, however. Drag left or right to control the opacity of the SpotLight images. Drag left to reduce opacity; drag right to increase opacity. A low opacity makes it easier to see the surface while projecting images onto your model. A medium level of opacity is helpful when you are using SpotLight as a sculpture reference.
Fade This does control the opacity of the image as it is projected onto the surface. You can vary the opacity of overlapping images to blend them together in SpotLight and then project the result onto a surface.
Tile Proportional Click this icon to arrange the images in SpotLight on the left side of the canvas. The images are scaled down to fit on the screen, but their relative sizes are maintained. The image that is the largest size will be the largest on the screen, and then the next largest size image will be the second biggest on screen, and so on down to the smallest image.
Tile Selected Click this icon to arrange the images on the left side of the canvas. The selected image is shown at full size, and unselected images are scaled down and placed below the selected image.
Tile Unified Click this button to arrange the images on the left side of the canvas. The images are all scaled to the same size.
Front Click this image to move the selected image to the front. The unselected images are placed behind. This becomes more apparent when the selected image is overlapping another image.
Back Click this icon to move the selected image to the back. The unselected images are placed in front. This becomes more apparent when the selected image is overlapping another image.
Delete This function removes the selected image from SpotLight.
Flip H This function flips the image horizontally.
Flip V This function flips the image vertically.
Tile H This tiles the images horizontally. To use this function, select an image by clicking it and drag the icon clockwise. As you drag, the image is repeated horizontally. If no images are selected, then this function is applied to all the images in Light Box. If you hold down the Shift key when moving this button, it will tile the texture horizontally and vertically and respect aspect ratio.
Tile V This works just like Tile H but the images are tiled vertically instead of horizontally.
Grid This applies a grid or a checkerboard pattern to the image. Drag the icon counterclockwise to add a grid. As you drag to the right, the squares of the grid are enlarged. Drag clockwise to add a checkerboard pattern. As you drag to the left, the squares of the checkerboard are enlarged. When you release the icon, the grid is applied to the image. If you drag the icon again, a new grid is applied to the image in addition to any existing grid. This function works only when an image is selected.
Restore This function restores the image to its original state. To use this, select the image and drag the restore icon clockwise. As you drag, the changes made to the image will fade away. If you keep dragging, eventually the image will be completely restored.
Some of the SpotLight functions, such as restore, can be applied to the whole image or just parts of the image. If you click the icon and drag it counterclockwise, the restore function is applied to the whole image. If you click the icon and then drag on the image, the restoration occurs only where you paint on the image. The Draw Size, Focal Shift, and ZIntensity sliders will determine the size, falloff, and intensity of the restoration effect.
Nudge This function is used to smear the image. To use this feature, click the nudge icon to activate it and then paint on the image. As you paint, the image will be smeared. The Draw Size and ZIntensity sliders on the top shelf control the size and the strength of the smearing. If you click the nudge icon and drag left or right, the strength of the nudged areas is reduced. If you drag the icon far enough, the nudged strokes will disappear altogether.
Clone This function copies part of an image to other parts of the same image or other images that have been loaded into SpotLight. To use this function follow these steps:
1. Place the center of the SpotLight interface over the area that you want to clone. This is the clone source.
2. Click the clone icon to activate it.
3. Drag on another part of the image or another image loaded within SpotLight. The area at the center of the SpotLight interface will be copied to wherever you paint. If there is an image selected, when you click another image, the image will be selected instead of being cloned.
4. Use the Draw Size and ZIntensity sliders to determine the size and opacity of the cloned image.
5. To reposition the clone source, drag on the edge of the circle at the center of the SpotLight interface.
The cloned stroke will not be applied to blank parts of the canvas. It appears only on images loaded into SpotLight. The clone feature is very useful but can be tricky. Watch the SpotLightClone.mov movie in the Movies folder on the DVD to see a demo that better explains this feature.
Smudge This is similar to nudge. If you select this icon and drag left or right, the selected image is blurred. Click this icon and drag on the image to create smudged strokes. The Draw Size and ZIntensity sliders on the top shelf control the size of the smudge and the intensity.
Contrast Click this icon and drag clockwise to increase the contrast of the image; drag counterclockwise to reduce contrast. As the dark colors in the image reach 100 percent black, they will appear transparent. Click this icon and drag on the image to paint areas of high contrast. The Draw Size and ZIntensity sliders control the size of the stroke and the intensity of the contrast. Hold the Alt key to paint areas of low or negative contrast.
Saturation The feature works very much like contrast. Drag the icon clockwise to increase the saturation of the color; drag counterclockwise to remove saturation. Click the icon and drag in the image to paint saturation into the image. Hold the Alt key and paint to remove areas of saturation. The Draw Size and ZIntensity sliders control the size of the stroke and the intensity of the saturation.
Hue Click the Hue icon and drag clockwise or counterclockwise to adjust the hue of the image.
Intensity This feature works very much like contrast and saturation. Drag the icon clockwise to increase the intensity of the color, and drag counterclockwise to remove intensity. If you keep dragging counterclockwise, eventually all the colors in the image become 100 percent black and the image becomes transparent. Click the icon and drag in the image to paint color intensity into the image. Hold the Alt key and paint to remove areas of intensity. The Draw Size and ZIntensity sliders control the size of the stroke and the color intensity.
Paint Click and drag clockwise on this icon to fill the image using the main color in the color picker. Drag counterclockwise to fill the image with the secondary color in the color picker. Click and drag in the image to paint colored strokes on the image. The colors are determined by the main color in the color picker. Hold the Alt key and drag in the image to paint with the secondary color. The Draw Size and ZIntensity sliders control the size of the stroke and the opacity of the color. Hold the Ctrl key to smart-fill selected color. Remember, black is seen as transparent. This will allow you to mask out parts of the textures. Watch the SpotLightPaint.mov video in the Movies folder of the DVD to see how this can be useful.
This concludes a brief tour of the SpotLight functions. To make sense of all this, you’ll need to practice. In the next few sections you’ll get some practical experience using SpotLight to perform a number of tasks.
SpotLight’s power lies in its ability to project the images you edit in SpotLight directly onto the surface of a digital sculpture. This means it’s very easy to incorporate photographic elements as well as digital painting and custom textures into the colors you paint on your models.
In the following sections, we’ll take a look at the basics of how to project images onto a surface using SpotLight.
Project an Image
Imagine shining a spotlight onto a surface, but rather than seeing just a bright light on the surface, you saw an image instead. That’s kind of the idea behind SpotLight. The sculpting brush is kind of like the spotlight and you use it to project images onto the surface. The process is very simple but very powerful. This exercise demonstrates a typical workflow for using SpotLight to project colors onto a surface.
1. Open a new session of ZBrush.
2. Use the Open button in the File menu to open the PolyPaintTest.ZPR project created earlier in this chapter.
3. Use the Load SpotLight button in the Texture palette to load the SpotLightTest.ZSL file created in the previous section.
4. When the SpotLight file loads, you’ll see the images on the canvas in front of the PolySphere. The SpotLight interface may be hidden. Press the Z hotkey to show the SpotLight interface.
When the SpotLight interface is visible, then you know that you are in image editing mode. This means you won’t affect the PolySphere behind the images when you drag on the canvas.
5. Select the largest image and drag it away from the others toward the center of the canvas.
6. Select each smaller image and move them out of the way so you have some space to work.
7. Click the largest image. Use the scale icon on the SpotLight interface to increase the scale of the largest image. To do this, click the scale icon and drag the SpotLight dial clockwise until the image covers the PolySphere behind it.
8. Drag on the largest image to position it in front of the PolySphere (see Figure 8-54).
Figure 8-54: Arrange the SpotLight images so that the largest image is in front of the PolySphere. Scale the image up so that it covers the PolySphere.
9. Click the opacity icon on the SpotLight dial. Drag counterclockwise until the image is almost completely invisible and you can clearly see the PolySphere (left image in Figure 8-55).
10. Click the SpotLight Radius button, and drag the dial clockwise to increase the size of the SpotLight radius. You’ll see part of the image appear as you drag within a faded circle. The circle increases in size when you drag clockwise (center image in Figure 8-55).
The SpotLight radius function does not affect the brush size. The radius feature creates a preview of the SpotLight image so you can see which parts of the image will be projected as you work. Increasing the radius lets you see more of the projected colors, but it does not affect how the colors will be projected onto the surface.
11. Press the Z hotkey. This hides the SpotLight interface and puts SpotLight into Projection mode.
12. Hold the tip of the brush over the PolySphere. You can see a preview of the projection at the center of the brush tip. This is the SpotLight style projection.
13. On the top shelf, turn off Add and make sure Rgb is on. Set Rgb Intensity to 80.
14. Click and drag on the surface. The image is projected onto the PolySphere (right image in Figure 8-55).
15. Rotate the PolySphere and paint some more. You can cover the whole surface by rotating and positioning the PolySphere within the projected area (see Figure 8-56).
Continue with this project in the next section.
Figure 8-55: Reduce the opacity of SpotLight (left image), increase the SpotLight radius (center image), press the Z hotkey to enter projection mode, and drag on the surface (right image).
Figure 8-56: Rotate the view of the PolySphere and continue to paint on it to cover the surface with the projected image.
Pin the Projection to the Brush
When SpotLight is in Projection mode, the images remain fixed exactly as they have been arranged. SpotLight projects straight through the image onto the surface. If you want to use the location of the brush to place the image, you can use the pin function.
1. Press the Z hotkey to reenter SpotLight image editing mode.
2. Click the thumbtack icon in the upper right of the SpotLight dial. A white bar appears above the icon, indicating that the pin function has been enabled (see Figure 8-57).
Figure 8-57: Press the pin icon on the SpotLight dial to turn on the pin function.
3. Press the Z hotkey again to hide the SpotLight dial and return to Projection mode.
4. Drag on the surface of the model. Lift the brush and drag on another part of the surface.
Each time you release the brush and paint on another part of the surface, the projected image is placed at the point where the brush makes contact with the surface. The center of the projection source is based on the center of the SpotLight dial relative to the position of the image in SpotLight (see Figure 8-58).
Figure 8-58: The projected image is pinned to the brush, so each time you touch the surface, the image is projected based on brush placement.
Continue with this project in the next section.
Blend Images Together Using Fade
Using the Fade function, you can control the opacity of the image as it is projected onto the surface. You can use this feature to blend two or more images in SpotLight and then project the result.
1. Press the Z hotkey to reenter SpotLight image editing mode.
2. Drag the opacity icon clockwise until you can see the images clearly.
Figure 8-59: Click the back button to send the selected image behind the other images.
3. Click and drag on one of the smaller images, and drag it over so that it overlaps the larger image. The smaller image may not be visible when it overlaps the larger image; this is because it is behind the larger image.
4. Select the large image by clicking it, and press the back icon on the SpotLight dial. The smaller image should appear now that the largest image has been sent all the way to the back (see Figure 8-59).
5. Click the smaller image to select it. The red border of the image indicates that is selected.
6. Drag the scale icon clockwise to enlarge the smaller image. The two images should be overlapping and the PolySphere should be behind both.
7. On the dial, drag the fade icon counterclockwise to decrease the opacity of the selected image (Figure 8-60). Set the fade of the selected image to about 50 percent of its original opacity.
Figure 8-60: Reduce the opacity of the overlapping image by dragging the fade icon counterclockwise
8. Drag the center of the SpotLight dial so that it is above an area where the two images are overlapping.
9. Press the Z hotkey to leave the image editing mode and enter Projection mode.
10. Drag on the surface of the PolySphere. The resulting projection is the combination of the two overlapping images blended together (see Figure 8-61).
Figure 8-61: The blended images are projected onto the PolySphere.
Sculpt with SpotLight
SpotLight not only projects the colors of the images onto the surface, it can also be used to sculpt the surface based on the values of the projected images. To enable this ability, you simply need to turn on Zadd on the top shelf while in Projection mode. Any of the sculpting brushes can be used to create a wide variety of texturing effects. The projected image acts as a stencil for the sculpting brush. The darker values of the image mask the effect of the brush.
This exercise shows how to enable this feature.
1. Start a fresh session of ZBrush.
2. Open Light Box to the Projects section.
3. Double-click the DefaultCube.ZPR project. This will load it into ZBrush.
4. Turn off the Persp button on the right shelf. Rotate the view of the cube so that you can see it from the side.
5. Open the SubTool subpalette of the Tool palette. Click the paintbrush icon for the PolyCube_1 subtool to activate Colorize mode.
6. Press Ctrl+D three times to subdivide the model. The model should be 1.572 million polygons at the highest subdivision level.
7. Open Light Box to the Texture section. Scroll to the left by dragging on the images until you find the blue grate texture. It is labeled IMG_4760.jpg (see Figure 8-62).
Figure 8-62: Select the blue grate image from the Textures section of Light Box.
8. Double-click this image to load it into SpotLight (you may need to double-click it twice).
9. Drag the scale icon on the SpotLight dial counterclockwise to reduce the size of the image.
10. Drag the opacity icon on the SpotLight dial counterclockwise to reduce the opacity of SpotLight so that you can easily see the cube.
11. Drag the SpotLight radius icon on the SpotLight dial clockwise to increase the radius of SpotLight (see Figure 8-63).
12. Press the Z hotkey to leave the image editing mode.
13. Open the sculpting brush fly-out library and select the Layer brush.
14. On the top shelf, turn on the Zadd and Rgb buttons. Set ZIntensity to 50 and Rgb Intensity to 10.
15. Set Draw Size to 100.
16. Drag on the surface of the cube. You’ll see the colors of the grate image appear on the surface, and you’ll also see the details of the image sculpted into the geometry of the cube (see Figure 8-64).
Figure 8-63: Increase the SpotLight radius.
Figure 8-64: The sculpting brush sculpts the details of the image into the surface of the cube.
Try this technique with other sculpting brushes. Try Planar Cut, Clay Buildup, or Blob. Note that you can use all of your sculpting tricks in combination with SpotLight. This means you can use alphas on the sculpting brushes, masks, BackTrack, stencils, and so on. It’s amazing how many interesting effects you can achieve using SpotLight as a sculpting tool.
Image Resolution and SpotLight
You’ll get better results in your SpotLight projection techniques if you use high-resolution images. Any image artifacts in the projected textures will affect the quality of the surface. So even if your model has been subdivided to millions and millions of polygons, if you project through a low-resolution or highly compressed image, the result will look blocky and pixilated.
Symmetrical Projection
Use symmetry when projecting SpotLight onto a surface in order to paint both sides of an object at the same time. For example, this technique can be used to paint two sides of a face using the same image.
This exercise demonstrates how this works.
1. Start a new session of ZBrush.
2. Open Light Box to the Project section and double-click the DemoDog.zpr project to load it into the current session.
3. Set the main color to white using the color picker.
4. Open the texture fly-out library on the left shelf. Click the Import button. Use your computer’s file browser to load the houndDog.jpg image from the Chapter 8 folder on the DVD.
5. Open the texture fly-out library and click the Add To SpotLight icon in the lower left (see Figure 8-65).
Figure 8-65: Add the houndDog image to SpotLight.
6. Use the SpotLight dial to scale the image down a little and move it towards the center of the screen.
7. Press the Z hotkey to exit image editing mode.
8. Scale the view of the dog model so that it matches the size of the head in the image. Rotate the view of the dog to match the angle of the head as well. It will be impossible to get a perfect match, but that is okay; just try to get it close.
9. Press the Z hotkey to switch back to the SpotLight image editing mode.
10. Scale and rotate the image using the SpotLight dial to see if you can make the image line up with the model a little better.
11. Click the nudge icon so that a bar appears above the icon. Drag on the image to push the pixels of the image. Use nudge to make the image match the model of the dog. Use the Draw Size and ZIntensity sliders on the top shelf to adjust the radius of the brush and the strength of the nudge effect (see Figure 8-66).
Figure 8-66: Rotate and scale the view of the dog model to match the SpotLight image (left image). Rotate the SpotLight image to match the view of the model (center image). Use nudge to push parts of the image to match the model.
12. Drag counterclockwise on the opacity icon to reduce the opacity of the image. Remember, this does not affect the opacity of the projection, just the opacity of the image. This makes it easier to see what’s going on when you start to project the image onto the model.
13. Press the Z hotkey to switch out of the SpotLight editing mode.
14. Press Ctrl+D three times to subdivide the model.
15. Make sure Zadd is off and Rgb is on. Set Rgb Intensity to 80.
16. Paint on the face of the dog to project the image.
17. Press Shift+Z to hide SpotLight. Rotate the view of the dog. The image has been projected onto both sides (see Figure 8-67).
Figure 8-67: The image of the dog is projected onto the dog model. With symmetry enabled, the image is projected onto both sides of the model.
Using symmetrical projection and the SpotLight nudge feature, it’s not hard to texture an entire face very quickly. If you have a series of images from different views, then you can easily blend the projections together to create a convincing texture. The amazing thing is that you don’t have to struggle with making sure everything lines up perfectly. You can easily edit each image in SpotLight to match the view of your model.
Sculpting Reference in SpotLight
SpotLight can be used as a convenient way to load reference images into ZBrush. This can eliminate the need to have to switch to an image editing program or a web browser while sculpting, allowing you to stay comfortably within the ZBrush environment.
My original vision for the hot rod body created in Chapter 5 was to create a sculpture of a cartoon car in the monster art style of Ed Roth. I created a quick sketch of what I thought the end result should be. In this exercise, you’ll see how the sketch can be used as a reference for sculpting the body.
1. Start a new session of ZBrush.
2. Use the Open button in the File palette to open the HotRodModel.ZPR project from the Chapter 8 folder on the DVD.
This model was created by combining the hot rod body, wheel, and headlight models created in Chapters 5 and 6 (see Figure 8-68).
Figure 8-68: The hot rod model is made up of tools created in Chapters 5 and 6.
3. Open the Texture palette and click the Import button. Load the hotRodRef.psd file from the Chapter 8 folder on the DVD.
4. Open the Texture palette and click the Add To SpotLight button. The image appears on the canvas in SpotLight (see Figure 8-69).
Figure 8-69: Import the image and click the Add To SpotLight icon in the Texture palette.
5. Drag counterclockwise on the scale icon to scale the image down. Move it off to the side so that you can see the model.
6. If you have a large number of images on the canvas in SpotLight, take a few minutes to arrange them so that you can see the model on the canvas.
7. Drag counterclockwise on the SpotLight radius icon all the way to make sure it is set to 0.
8. Press the Z hotkey to switch out of SpotLight Edit mode.
9. Open the Brush palette and expand the Samples subpalette. Turn off the SpotLight Projection button (see Figure 8-70).
Figure 8-70: Turn off the SpotLight Projection button in the Samples subpalette of the Brush palette.
This last step is the most important. If you don’t turn off SpotLight projection, the sculpting brushes will not work unless they are used to project colors and details on the surface. If the images disappear when you press the Z hotkey, it means you need to set the SpotLight radius to 0. Doing this keeps the images visible when SpotLight Edit mode is off (see Figure 8-71).
Now you are free to model the surface. Press Z whenever you want to toggle back into SpotLight and rearrange the images. Press Shift+Z when you want to hide SpotLight completely.
Figure 8-71: Model the car with the reference images in the background.
Check out the engineRefImages.ZSL SpotLight file in the Chapter 8 folder of the DVD. I created this SpotLight from photographs I took of a hot rod parked on my street.