Chapter 3
Basic Digital Sculpting
Digital sculpting refers to a brush-based approach to creating three-dimensional models on a computer. ZBrush revolutionized the computer game and entertainment industry as well as digital art by introducing its unique digital sculpting technology about 10 years ago. Since then, the older methods of pushing and pulling polygon vertices and faces has largely been replaced with digital sculpting. Digital sculpting in ZBrush offers a much more intuitive and artistic way to create models. This is what has made ZBrush so attractive to artists who are less interested in the technical aspects of computer software and more concerned with creating great artwork.
In this chapter, you’ll be introduced to the basics of digital sculpting in ZBrush. By the end of this chapter, you’ll understand the following fundamental ZBrush concepts:
- Working with digital clay
- Subdividing a mesh
- Using sculpting brushes
- Activating and adjusting symmetry
- Masking
- Polygon selection and visibility
Digital clay is a term affectionately applied to a polygon mesh in ZBrush. This type of mesh is a surface made up of connected polygon faces. Each face shares vertices and edges with neighboring polygon faces (see Figure 3-1). ZBrush allows the polygon faces to be made up of three- or four-sided polygons. These meshes are called digital clay because of the way in which they are shaped by the sculpting brushes. Shaping polygon meshes with the brushes feels so intuitive that it’s a lot like working with clay.
Figure 3-1: Digital clay is a polygon mesh made up of three- or four-sided polygons.
Digital clay is shaped directly on the ZBrush canvas while the mesh (also known as a 3D tool) is in Edit mode. Digital clay can be generated a number of different ways. You can use one of the premade models that comes with ZBrush, or you can import a polygon model created in another software package such as Modo or Maya. ZBrush can automatically “skin” an armature made of the special ZSphere tool, you can use a tool known as ShadowBox to create a mesh from a painted silhouette, and you can extract a new mesh from part of an existing model. Skinning refers to the process of wrapping a polygon mesh around ZSpheres; this is covered in detail in Chapter 4, “Subtools, ZSpheres, and ZSketching.” Using ShadowBox and extracting meshes are covered in Chapter 5: “Shadow Box and Clip Brushes.” Importing models from other software packages is covered in Bonus Content 1, “GoZ.”
In this chapter, we’ll keep it simple and use one of the preset models that come with ZBrush. You’ll start a project using the humble PolySphere tool that comes with ZBrush. The PolySphere is essentially a rounded cube. It responds well to the sculpting brushes because, unlike a typical polygon sphere, the PolySphere does not have poles at either end which tend to become pinched and difficult to work with when using the sculpting brushes (see Figure 3-2). Because of the lack of poles, the PolySphere is said to have a good “topology” for digital sculpting.
Figure 3-2: The PolySphere on the left has an arrangement of polygons better suited for digital sculpting than the sphere on the right.
Topology
In the world of digital 3D modeling, the term topology is used to refer to how the polygon faces that make up a 3D mesh are arranged on the surface. There are different methods for creating topology. Some topologies are better suited for digital sculpting than others. To create the best possible motion for the creatures and characters they animate, animators working in 3D software have special requirements for the topology of the models they use. If you intend to create models for use in video games or in animation, you will need to become very conscious of topology. ZBrush even has tools to allow you to re-create the topology of a model after you have sculpted it.
Load the PolySphere
In this exercise you’ll learn how to load the PolySphere tool onto the ZBrush canvas and how to prepare it for digital sculpting:
1. Start ZBrush if it’s not open already.
2. To ensure that you are starting with a clean slate, go to the Preferences palette at the top of the screen and press the Init ZBrush button.
Figure 3-3: A warning message appears when you initialize ZBrush.
3. A warning appears asking you if you want to fully initialize ZBrush (see Figure 3-3). Click Yes.
The Init ZBrush button initializes ZBrush, ensuring that all the controls have been set to their default settings and all custom tools have been removed from the toolbox for the current ZBrush session. Make sure you save the work you want to keep before initializing ZBrush.
Saving ZBrush Files
When you’re first learning ZBrush, you’ll want to save your files as a ZBrush project. This ensures that the next time you load the project file, you can pick up where you left off and nothing is lost. Later on, you’ll learn how to save individual elements such as 3D tools, textures, brushes, and more. To save a ZBrush project, use the Save As button in the File palette at the top of the screen. The project is saved in the special ZPR format. You can save the project anywhere you like on your hard drive. If you’d like the project to appear in the Project section of Light Box, save it in the ZBrush 4.0Projects directory. On Windows, this is located in the Program Files directory. On the Mac, it is found in the Applications directory. For more on working with Light Box, consult Chapter 2.
Figure 3-4: Double-click the PolySphere icon in Light Box to load it into ZBrush.
4. Place the mouse pointer at the bottom of the screen to bring up Light Box. Click the Tool link to see the contents of the ZTools folder.
5. Scroll the Light Box icons by dragging the area between the icons to the left. Find the PolySphere icon and double-click it (see Figure 3-4).
You may notice that it looks as though nothing happens when you double-click the PolySphere. But take a look in the Tool palette that is docked in the tray on the right side of the canvas; the large icon in the upper-left corner has switched from the SimpleBrush to the PolySphere, indicating that the PolySphere is now the current ZBrush tool (see Figure 3-5).
Figure 3-5: The large icon in the upper-left corner of the Tool palette represents the current tool.
Light Box gives you a visual preview of the files located on your disk within the Pixologic subdirectories; this includes things such as 3D meshes. But these files may not be loaded into the current ZBrush session, at least not until you double-click them.
In the case of the files in the Tool section of Light Box, when you double-click them they will then be loaded in ZBrush. Once a tool is loaded, it means that it is ready for you to use and edit. All the tools available for the current ZBrush session are found in the Tool palette. The current tool is in the upper left and smaller icons of other tools that are available for quick access surround it. To see all the tools available for the current session, click the large icon in the upper left of the palette to open up the inventory of available tools (see Figure 3-6).
Figure 3-6: The tool inventory separates the available tools into three sections.
Recently used tools are found in the top section of the inventory listed under Quick Pick. The current tool will appear grayed out in the inventory. The other two sections are divided between 3D tools and 2.5D brushes. Clicking another tool icon will make that tool the current tool.
6. Drag on the canvas. You’ll see the PolySphere appear and grow as you drag. Let go and drag on another part of the canvas—another PolySphere appears.
Figure 3-7: The PolySphere tool draws copies of PolySpheres all over the canvas.
Every time you drag on the canvas, a new PolySphere appears. If you drag on existing PolySpheres, new PolySpheres appear on top (see Figure 3-7). What’s going on?
Currently you are in Draw mode, meaning that the PolySphere tool is drawing copies of itself on the canvas. This is why ZBrush uses the term tool. The PolySphere is a tool for painting PolySpheres on the canvas. So how do you sculpt the PolySphere? You have to switch to Edit mode.
7. Press Ctrl+N to clear the canvas.
8. Drag on the canvas to create a new PolySphere.
9. Press the Edit button on the top shelf (hotkey = T).
10. Right-click (or hold the button on the pen if you’re using a tablet) and drag on the canvas. This time you’ll see that the PolySphere rotates. When this happens, you’ll know you’re in Edit mode.
Edit Mode
Edit mode has been known to trip up many new ZBrush users and it can cause some frustration at first. Often you’ll find that you somehow accidentally move out of Edit mode (perhaps by inadvertently pressing the T hotkey) and when you try to sculpt on the surface of a model, a new copy of the model appears instead. And as you continue to draw strokes, more copies of the model appear. To stop this behavior, just remember these simple steps:
1. Press Ctrl+N to clear the canvas.
2. Drag on the canvas to add a copy of the model on the canvas.
3. Press the T hotkey to switch to Edit mode.
4. Continue working on your model.
What is the deal with Edit mode anyway? It makes more sense when you learn that ZBrush began as an innovative illustration tool. The 3D tools are special paintbrushes designed to paint copies of 3D objects on the canvas. Edit mode is used to change the shape of the 3D objects painted on the canvas. While in Edit mode, ZBrush stores the changes made to the 3D tool, keeping an update while you work. When you turn off Edit mode and paint on the canvas, the edited version of the object now appears.
As a digital sculptor, you may not be interested in painting pictures with your edited 3D objects. In this case, you’re going to be working in Edit mode most of the time. But it’s important to understand what Edit mode is in case you encounter a type of behavior you don’t understand.
If you are working on a digital sculpture while Edit mode is active, save the project using the Save As option in the File menu. The next time you load the project, you’ll find that your sculpture is saved in Edit mode.
Figure 3-8: The Standard brush is the current sculpting brush.
11. Look in the top of the left shelf. The Standard brush should be loaded as the current sculpting brush (see Figure 3-8). If the icon for the Standard brush is grayed out, it means you’re not in Edit mode. Make sure you’re in Edit mode.
Figure 3-10: The Floor button activates the visibility of the grids.
12. Drag across the surface of the PolySphere. You’ll see the surface raise up as you drag. Congratulations! You have just entered the world of digital sculpting! The result is shown in Figure 3-9.
Figure 3-9: Dragging across the surface of the PolySphere creates a raised line.
13. Right-click drag on the canvas to rotate the model. As you are dragging, hold down the Shift key. You’ll see the model snap to an orthographic view (orthographic views are side, top, and bottom views).
14. To get a better sense of this, turn on the Floor button on the right shelf so that you can see the grid. . You can also turn on any combination of the three letters.
15. Right-click drag again and press the Shift key while dragging. The view snaps to the closest orthographic view as you drag.
16. To center the view of the PolySphere in the canvas, press the Frame button on the right shelf (hotkey = F).
While in Edit mode, you are working on a virtual sculpture stand. Right-click navigation will help you adjust the view of your model as you work (holding the button on your stylus is the same as right-clicking with your mouse):
Right-click drag = rotate view
Alt+right-click = move view
Ctrl+right-click = zoom view
17. On the File palette above the top shelf, choose File ⇒ Save As. Save the file as practiceClay.ZPR. Save the file in the ZBrush 4.0/ZProjects directory. This is found in the Program Files folder under Windows or in the Applications folder on the Mac (see Figure 3-11).
Figure 3-11: Save the project in the ZProjects folder.
Okay, you’re on your way to digital sculpting. The first time you go through this it seems like a lot of steps, but before you know it this will be second nature for you. By saving the file in the ZProjects folder, you’ll see the icon in the Projects section of Light Box.
Using Standard, Smooth, and Move Brushes
Sculpting brushes shape digital clay by moving the polygons around. The brushes do not add or remove polygons, they do not subdivide them, they just move the existing polygons in the mesh in different ways. That doesn’t sound like much, but sculpting brushes are actually extremely powerful. Shaping a mesh through the use of sculpting brushes feels very natural. It is so intuitive it may make you wonder how any one created any kind of 3D digital model before ZBrush came along.
If you take a look in the sculpting brush fly-out library on the left shelf, you’ll see that there are a lot of brushes (see Figure 3-12). Each has its own way of shaping digital clay.
In the following exercises, you’ll learn the basics of using sculpting brushes starting with the three most essential brushes: the Standard, Smooth, and Move brushes.
Where to Find the Sculpting Brushes
The sculpting brushes are located in the fly-out library at the top of the left shelf, not in the Tool palette. Try not to confuse the sculpting brushes with the 2.5D brushes found in the lower section of the tool inventory. These are very different types of brushes used for drawing on the canvas, not for shaping digital clay.
Figure 3-12: The fly-out library contains a large number of sculpting brushes.
The Standard Brush
The Standard brush raises the surface of the digital clay. As you touch and drag on the surface of the clay with the Standard brush, ZBrush samples the direction of the normals underneath the brush tip, averages their direction, and then moves the surface in an upward direction based on that average. That explanation was very technical, so let’s take a look at what this means.
The surface of digital clay is made up of a large number of connected polygon faces. Each polygon face is a square or a triangle. Imagine a line perpendicular to the center of each polygon face (see Figure 3-13). This line represents the face normal.
Figure 3-13: The left image shows a single polygon face. The white arrow represents the direction of the face normal. The right image shows a curved polygon mesh. Each polygon face in the mesh has its own face normal.
The direction of the face normal has a large impact on how the sculpting brush changes the surface. The brushes use a number of different algorithms that take the face normal direction into account when they modify the surface. It’s not necessary to know anything about the specifics of these algorithms to use ZBrush. And ZBrush is not designed for math geniuses; it’s made for artists regardless of their level of math skill. However, it’s a good idea to have a basic understanding of what a face normal is and that each brush has a different way of altering the surface based on the direction of the face normals.
Figure 3-14: The tip of the sculpting brush is represented by a disc that orients itself to the surface of the digital clay.
As you apply the standard sculpting brush to the surface of digital clay, you’ll notice a disc that hovers above the surface (see Figure 3-14). The orientation of the disc changes as you move the brush over the surface, even when you are not pressing down on a digital tablet.
Imagine a short conversation that takes place between the tip of the brush, represented by the disc, and the surface of the digital clay. The brush is asking the surface questions about the direction of the face normals, the number of polygon faces within the area of the brush tip, whether a mask has been applied to the surface, and so on. As you drag on the surface, the information is continually updated. The act of gathering information about the surface is known as sampling, and this is a big part of how the behavior of the sculpting brushes is determined. We’ll return to the topic of sampling in Chapter 7, “Advanced Brush Techniques.”
Figure 3-15: The brush controls on the top shelf
Let’s take a look at how the settings on the top shelf affect the way the Standard brush behaves (see Figure 3-15).
Follow these steps:
1. Load the practiceClay.ZPR project that you saved at the end of the previous section or load a PolySphere on the canvas and switch to Edit mode.
2. Make sure the Standard brush is shown in the right shelf (Figure 3-16). If it is not, click the brush icon at the top of the left shelf to open the brush fly-out library and select the Standard brush.
On the top shelf you’ll see the Zadd and Zsub buttons, which indicate the brush drawing mode. For the Standard brush, when Zadd is on the brush will cause the surface to move outward toward the brush tip. When Zsub is activated, the brush will cause the surface to move inward away from the brush tip (see Figure 3-17).
Figure 3-16: The Standard brush is the currently active brush when its icon appears on the left shelf.
While sculpting a model, you’ll most likely be switching between Zadd and Zsub a lot as you shape the surface. Rather than constantly move back and forth between the canvas and the top shelf, you can use the Alt key to switch modes.
3. Make sure the Zadd mode is activated on the top shelf. Drag across the surface of the PolySphere a few times to make some marks. The surface will move outward as you touch it with the brush.
Figure 3-17: Zadd mode pulls the surface outward toward the brush tip, shown on the left side of the PolySphere. Zsub pushes the surface inward, shown on the right side of the PolySphere.
4. Hold the Alt key and make a few more marks. The surface now pushes inward away from the brush tip.
The Alt key essentially switches to the opposite mode. In other words, if the Zadd button is activated on the top shelf, then holding the Alt key will activate the Zsub mode. If Zsub is activated on the top shelf, then holding the Alt key will activate Zadd mode (see Figure 3-18).
Figure 3-18: Hold the Alt key to toggle the Zsub mode while sculpting with the Standard brush.
Search the Brush Library
The brush fly-out library contains a large number of brush presets. If you know the name of the brush you are looking for, you can speed up your search by typing the first letter of the brush’s name while the fly-out is open. For example, if you are looking for the Standard brush, just type s. You’ll see all the brush icons become grayed out except those that start with s. This makes it easier to spot the Standard brush.
You’ll also notice, as shown in the following image, that each brush has a letter in the upper-left corner of its icon. If you type this letter while the brush fly-out library is open, ZBrush will set the brush preset as the currently active brush. For example, typing s and then t while the brush fly-out library is open will automatically set the current brush to the Standard preset. Typing c and then l while the brush fly-out library is open sets the current brush to the ClayLine brush preset.
Below the Zadd and Zsub buttons, you’ll see the Z Intensity slider. This slider sets the overall strength of the brush. When you lower Z Intensity while using the Standard brush, it takes more strokes to move the surface. A higher Z Intensity value increases the strength of the brush so that the surface deforms with only a few strokes.
5. Set Z Intensity to 5 by moving the slider to the left. (You can also select the slider in the interface and type 5 to set it to a specific number.)
6. Make some marks on the surface of the PolySphere. Use the Alt key to switch between Zadd and Zsub.
7. Set Z Intensity to 100 and make some more marks. Notice the difference; the higher Z intensity value creates a much more immediate change in the surface.
Figure 3-19: Hold the U hotkey to display the Z Intensity slider on the canvas for quick access.
While sculpting with a brush, press the U hotkey to display a copy of the slider on the canvas near the brush tip (see Figure 3-19). This will allow you to adjust Z Intensity while you work without having to go up to the top shelf. Move the slider back and forth to adjust the intensity. The slider disappears from the canvas and Z Intensity is set once you release the slider.
Pressure Sensitivity and Z Intensity
The Standard brush is pressure sensitive, which will affect Z intensity. If you’re using a digital tablet, pressing harder on the surface will cause the brush to meet the maximum value specified by the Z Intensity slider. Pressing lightly causes the stroke to have less of an effect on the surface. In Chapter 7, you’ll learn how to use the pressure sensitivity controls in the Brush palette to change this behavior and design your own custom brushes.
Figure 3-20: The Focal Shift slider controls the brush intensity falloff, illustrated by the space between the inner and outer circle of the brush tip.
The next slider on the shelf is the Focal Shift slider. This sets the hardness of the edge of the brush tip. If you take a look at the disc that represents the brush tip, you’ll see that there are two concentric circles.
The outer circle displays the outer edge of the brush. The surface of the digital clay is affected only within the area of the brush’s outer edge. There is a falloff of strength that occurs between the center of the brush and the outer edge, which helps create a smoother deformation of the surface. The inner circle of the brush tip display represents the size of the falloff (see Figure 3-20).
Move the Focal Shift slider on the top shelf to the right to increase the distance between the outer edge and the inner circle. This gives marks made by the brush a softer edge. Move the Focal Shift slider to the left to decrease the space between the outer edge and the inner circle, giving the brush a harder edge.
8. Make some more marks on the PolySphere. Adjust the Focal Shift slider and note how this changes the style of the brush marks made on the surface.
9. Press the O hotkey to display the Focal Shift slider on the canvas near the brush. This makes it easier to adjust while you work.
The Draw Size slider adjusts the size of the brush’s outer edge and thus the size of the brush tip itself. Using Focal Shift and Draw Size, you can fine-tune the size of the brush tip of the Standard brush as well as the other brush presets available in the brush fly-out library.
10. Experiment using the Draw Size slider to change the size of the standard brush.
11. Press the S hotkey to display the Draw Size slider on the canvas near the brush tip.
Brush Size and View Scale
The draw size remains consistent regardless of the view scale of the mesh on the canvas. So if you hold the Ctrl key and right-click drag to scale the view up, the brush size will remain the same and affect a smaller part of the mesh. Likewise, if you scale the view down, the same brush size will affect a larger part of the surface.
The following screen shot illustrates how, even though Draw Size is set to 44, the amount of area affected by the brush is different if the view scale is large (left) as opposed to small (right).
The Smooth Brush
The Smooth brush evens out the area of a surface to create a smoother appearance. You can select the smooth brush from the brush fly-out library; however, since this brush is used a lot while sculpting, ZBrush has assigned the role of activating the smooth brush to the Shift hotkey. This way you don’t have to constantly go into the brush fly-out library to switch to the smooth brush. To practice using the Smooth brush, follow these steps:
1. Load the practiceClay.ZPR project that you saved at the end of the previous section or load a PolySphere on the canvas and switch to Edit mode.
2. Use the Standard brush to make marks on the surface of the PolySphere.
Figure 3-21: The Smooth brush evens out the surface creating a smooth appearance.
3. Hold down the Shift key and drag the brush over the marks you’ve made with the Standard brush (see Figure 3-21).
The marks in the surface seem to melt away as you brush over them while holding down the Shift key. The Smooth brush averages the distance between the vertices on the surface.
4. Increase the draw size of the brush and continue smoothing the surface. The smooth effect is stronger with a larger brush size because a larger area of the surface is being sampled as you brush.
5. Hold down the Shift key and adjust the Z intensity.
The Z intensity of the Smooth brush is independent of the current brush, meaning that the value changes when you switch to the Smooth brush. ZBrush remembers the Z intensity of the Smooth brush even when you release the Shift key and switch back to the Standard brush. This is also true of the Focal Shift setting but not Draw Size.
A high Z intensity, such as the default setting of 100, can quickly obliterate details sculpted into the mesh. It’s good practice to set the Z intensity of the Smooth brush to somewhere between 20 and 40 while working.
There are a number of other smoothing brushes available in the brush fly-out library and in the Brush section of Light Box. If you choose one of these brushes, you’ll get a message letting you know that the chosen smoothing brush will be active only while you are holding down the Shift key. The other smoothing brushes have unique properties that will make more sense after you’ve learned more about ZBrush.
Smooth Brush Size
The Brush palette contains a set of controls that are dedicated to the Smooth brush. These are found toward the bottom in the Smooth Brush Modifiers subpalette. This palette will be explained in detail in Chapter 7. For now it is useful to know that the Alt Brush Size slider adjusts the size of the Smooth brush. This value is a multiplier for the Draw Size setting. When you set Alt Brush Size to 2, every time you hold down the Shift key, the draw size of the Smooth brush will be twice the draw size of the current brush. A setting of 10 will make the Smooth brush 10 times the current brush size.
Relax Brush
The Smooth brush has an alternate relax feature that is activated by releasing the Shift key while the Smooth brush is active. To use this feature, you need to hold down the Shift key to activate the Smooth brush, drag on the surface of the mesh, and then release the Shift key and continue to drag the brush across the surface. The difference between smooth and relax modes is often very subtle.
The Move Brush
The Move brush pushes and pulls digital clay just as if you were stretching and squashing real clay with your hands. It’s one of the best ways to work out the basic shape of your sculpture, but it can be used to manipulate small parts of objects as well. To practice using the Move brush, follow these steps:
1. Load the practiceClay.ZPR project that you saved at the end of the previous section or load a PolySphere on the canvas and switch to Edit mode.
2. Click the brush icon at the top of the left shelf to open the sculpting brush fly-out library.
3. You can select the Move brush from the Quick Pick list at the top of the fly-out library or press m and then b while the fly-out library is open.
4. Click on the surface of the PolySphere and drag away from the center of the mesh. The Move tool pulls the surface and will continue to pull until you let go.
5. Increase the Z intensity to 100 and try pulling some more. The clay seems to stick to the brush tip until you let go.
6. When you lower the Z intensity, the result of using the Move brush becomes more like a nudge or smear. It takes more strokes to push the clay around.
Figure 3-22: The Move brush allows you to push and pull on the surface of digital clay. Adjust the Z intensity and focal shift and use the Alt key to modify the behavior of the brush.
7. Set the Z intensity to 50 and try adjusting the Focal Shift slider. At -100, the brush has a harder edge and you can move more of the clay. Using a Focal Shift of 100 adds a tapering effect to the movement. The effect of the Move brush is concentrated at the center of the brush tip.
8. As you drag out part of the surface, hold the Alt key. This causes the moved portion of the surface to move along the direction of the face normals (see Figure 3-22).
By holding the Alt key, you restrict the motion of the Move brush to the direction of the face normals. This is true when you push into the surface as well.
There’s much more to learn about the brushes, and you’ll get to explore many more types of brushes throughout this chapter. Before going on, spend some time making a mess out of the PolySphere in your practiceClay.ZPR project. Get a feel for using the Alt key to switch between Zadd and Zsub with the Standard brush. Adjust the Z Intensity, Draw Size, and Focal Shift settings. Experiment with the Smooth and Move brushes.
Move Brush Presets
There are a number of Move brush presets in the sculpting brush fly-out library as well as in the Brush section of Light Box. You’ll learn more about how these presets work as well as how to make your own variations in Chapter 7.
As stated earlier, digital clay in ZBrush is a mesh made up of polygon faces. ZBrush can easily handle a mesh with millions of polygons. The more faces a mesh has, the more detail can be sculpted into it, which is why ZBrush has become so popular for creating realistic creatures and characters. But how do you get a mesh with millions of polygons? It’s done through subdivision. ZBrush allows you to subdivide the mesh to increase the number of polygons in the surface, thus allowing for more detailed sculpting. ZBrush also keeps a history of the model at lower subdivision levels so that you can move back and forth between the original mesh and the subdivided mesh.
The ability to move freely between levels of subdivisions makes the task of modeling much easier. At lower subdivisions, you can rough out the major forms of a model; at higher levels, you can create fine detail. At any point during the sculpting process, you can move back down to a lower subdivision level and make changes, and the details at the higher subdivision levels will still be there.
To see how this works, try this exercise:
1. Place your mouse pointer toward the bottom of the ZBrush interface to open Light Box or click on the LightBox button on the top shelf. Click the Project heading.
2. Double-click the DemoDog.ZPR project to load it on the canvas. The DemoDog project consists of a basic dog model.
3. Click the PolyF button on the left shelf to display the wireframe on the surface of the dog. This allows you to clearly see the polygon faces that make up the mesh.
4. Make sure the Tool palette is loaded in the tray on the right side of the canvas. Hold the mouse pointer over the large icon of the dog in the upper-left corner. You’ll see a small window pop up that displays statistics for the dog model (see Figure 3-23).
The statistics indicate that the dog mesh currently has 7,984 polygon faces (abbreviated as Polys) and 8,013 points.
5. In the Tool palette, expand the Geometry subpalette and press the Divide button, shown in Figure 3-24 (hotkey = Ctrl+D).
When you divide the mesh you’ll see that it appears smoother and the lines of the wireframe become denser.
6. Hold the mouse pointer over the dog icon in the Tool palette again to see the statistics pop up.
The dog model now has 31,936 polygons and 31,993 points. In the Geometry subpalette of the Tool palette, a slider labeled SDiv is now active. The slider is set to 2. This means that the dog mesh now has two levels of subdivision.
Figure 3-23: Hold the mouse pointer over the tool icon in the Tool palette to see mesh statistics.
Figure 3-24: Press the divide button to add a level of subdivision to the mesh.
7. Move the SDiv slider to the left to set it to level 1. This brings the dog model back to its original state of 7,984 polygons.
8. Move the SDiv slider to level 2 and press the Divide button again (hotkey = Ctrl+D). This adds a third level of subdivision. At this level the dog mesh has 127,744 polygons and 127,857 points.
As you increase the subdivision level on a mesh, the number of polygons increases by a factor of four since each polygon is divided into four smaller polygons. A mesh that has 24 polygons at SDiv level 1 will have 96 polygons at SDiv level 2, 384 polygons at SDiv level 3, 1,536 polygons at SDiv level 4, and so on. It doesn’t take very many subdivisions before a mesh reaches a million or more polygons.
Setting Subdivision Limits
In the Preferences palette, you can adjust the maximum number of polygons each mesh can have using the MaxPolyPerMesh slider in the Mem subpalette. This limit is specified in millions of polygons per subtool (a limit of 12 means 12 million polygons). At a certain point a model with millions and millions of polygons will start to slow down the performance of the software, but understand that ZBrush’s unique programming allows it to handle many more polygons per mesh than another 3D application would be able to on the same computer!
The SDiv slider lets you move up and down through the subdivision levels. You can also use the D hotkey to move to a higher subdivision level and Shift+D to move to a lower subdivision level. These hotkeys only move through existing subdivision levels.
Add Lower Levels of Subdivision
If you want to add a lower level of subdivision, use the Reconstruct Subdiv button in the Geometry palette. This button is active only when the SDiv slider is at level 1. The Reconstruct Subdiv button works if the number of polygons in the model can be divided evenly by 4. Be careful when using this feature. Using the Reconstruct Subdiv button can sometimes adversely affect details sculpted into the higher subdivision levels.
The Del Lower button deletes all subdivision levels below the current SDiv setting and sets the current SDiv level to 1. So if you’re on level 2 and you press the Del Lower button, all SDiv levels below 2 are removed and 2 now becomes 1.
The Del Higher button removes all subdivision levels above the current SDiv setting.
The Smt button is activated by default. This smoothes the mesh each time you press the Divide button. If this button is off, the hard edges of the model will be maintained as the model is divided.
Each time you subdivide the model using the Divide button, the SDiv slider should be at its highest setting, otherwise you’ll get a warning. In addition, if it looks as though nothing is changing when you divide the model, check to see whether the Smt button is off.
The symmetry feature copies changes you make on one side of a model to the opposite side. This is helpful when you want to sculpt a symmetrical object such as a face. What’s more, you can sculpt using multiple axes at the same time and use radial symmetry to quickly create ornate designs. The following steps demonstrate how to use symmetry in ZBrush:
1. Place your mouse pointer toward the bottom of the ZBrush interface to open Light Box. Click the Project heading.
2. Double-click the DefaultCube.ZPR project to load it on the canvas.
3. Open the sculpting brush fly-out library on the left shelf and press s and then t. This will set the current brush to the Standard brush.
Figure 3-25: Use the cursor in the central square of the color picker to choose white.
4. In the color picker on the left shelf, move the cursor within the central square to the upper-left corner to select a white color. This will make it easier to see the cube (see Figure 3-25).
5. Dock the Transform palette in the right tray.
Figure 3-26: Turn on Activate Symmetry in the Transform palette.
6. In the Transform palette, turn on the Activate Symmetry button (see Figure 3-26). The hotkey to activate symmetry is X.
7. Hold the brush tip over the front of the cube. You’ll see a second red dot. This dot indicates the position of the symmetrical stroke (see the top image in Figure 3-27).
8. Make some marks on the front of the cube. The marks you make are mirrored on the other side of the cube (see the bottom image in Figure 3-27).
By default, the symmetry is set to mirror strokes across the x-axis of the mesh. In the Activate Symmetry subpalette of the Transform palette, you’ll see that there are buttons for >X<, >Y<, and >Z<.
Figure 3-27: When symmetry is activated, you’ll see two red dots appear on the model (top image). Symmetry mirrors marks made with the sculpting brush across a specified axis (bottom image).
9. Turn on the >Y< button and make more marks on the cube. Now there are four red dots indicating that strokes are mirrored along both the x- and y-axes (see Figure 3-28).
You can use any combination of >X<, >Y<, and >Z<, or all of them together. This can be a great way to create elaborate designs. The >M< button mirrors the symmetry so that if you move to the right on one side, the symmetrical stroke moves to the left. If this is off, both strokes will move to the right.
Figure 3-28: Marks made on the surface of the cube are mirrored across both the x- and y-axis at the same time.
10. From the File palette, choose Revert to undo all the changes you have made to the cube. Set the color to white again.
11. In the Transform palette, turn on Activate Symmetry (hotkey = X) and turn on the (R) button. This activates radial symmetry.
Radial symmetry creates a ring of strokes, which can lead to some really interesting designs. The RadialCount slider sets the number of strokes.
12. Turn off the >X< button, turn on >Z<, and set RadialCount to 6.
13. Make some marks on the front of the cube (see Figure 3-29).
Figure 3-29: Radial symmetry is a great way to create elaborate patterns.
Radial symmetry is a great way to create interesting patterns on surfaces. Try combining radial symmetry with more than one axis (x, y, and z) and see what kind of shapes you can create.
Now that you have some fundamental ZBrush concepts down, it’s time to actually make something. In the following sections, you’ll build on what you’ve learned through the process of sculpting a dragon’s head. You’ll start with a simple lump of digital clay and shape it into the head of the classic fantasy beast. Along the way you’ll add to your repertoire of sculpting brushes and learn about masking, polygroups, and subtools.
Exploring Shapes
The first task is to find the shape for the dragon’s head. ZBrush is an organic medium, ideal for testing out ideas. In this exercise, you’ll see how you can play in ZBrush as you search for a shape that inspires your imagination. Digital sculpting is not about moving x number of vertices to such and such coordinates; it’s more about feeling your way toward a general goal. In this respect, I do not expect your dragon to look exactly like the example created in this book. In fact, at this point I have no idea what form the dragon I create will take. You may want to take a few minutes to research images of dinosaurs, lizards, snakes, and art created by fantasy masters. In particular, I find the fantasy art of John Howe very inspiring. Obviously, dragons are not real creatures, and the rules for creating them are pretty loose: If it looks like a dragon and breathes fire like a dragon, then it’s a dragon.
To create the basic head of the dragon you’ll start with a PolySphere. It’s a good idea to keep the mesh at a low subdivision level when you’re creating the initial shape. This helps you avoid the temptation of jumping into detail too early. Just as with any traditional medium, such as clay sculpture or drawing, the best approach is to focus on the primary forms such as the skull and bony parts first and then add secondary details such as the muscles and tertiary details such as scales and wrinkles later on.
Prepare for Sculpting
You’ll focus on the silhouette of the form as you find the shape. Keep away from working on details at this point; there will be plenty of time for that later on. The following steps demonstrate a good way to prepare for sculpting:
1. Open ZBrush and make sure the canvas is clear.
2. Open Light Box by moving the mouse pointer to the bottom of the screen. Click the Tool link and double-click the PolySphere.ZTL tool.
3. Drag your stylus across the canvas to create the PolySphere.
4. Press the T hotkey to switch to Edit mode.
5. Press the F hotkey to frame the PolySphere.
6. Make sure the Tool palette is docked in the right tray.
7. Press Shift+D twice to move down to the lowest subdivision level.
8. Press the X hotkey to turn on symmetry along the x-axis.
9. In the material fly-out library, select the Flat Color material. This will make the PolySphere appear solid white.
10. Rotate the PolySphere by right-click dragging on the canvas (hold the button on the stylus if you’re using a tablet). Hold down the Shift key as you drag to snap the view to the front. You’ll want to see two dots on the front of the sphere as shown in Figure 3-30. If you’re having trouble figuring out which is the side view, try turning on the Floor button on the right shelf. The grid display will help keep you oriented.
Figure 3-30: The PolySphere is placed on the canvas and is ready for shaping.
That seems like a lot of steps, but it actually becomes second nature fairly quickly. Now you’re set up and ready to sculpt. At this point you can save this as a project to avoid having to repeat these steps in the future.
11. Go to the File palette and choose Save As. Save the file as dragon_v01.ZPR in the PixologicProjects folder. This way it will appear in Light Box under the Projects heading, saving you the trouble of having to hunt for it later on.
The Flat Color Material
The Flat Color material is ideal when you’re just starting to explore shapes because it displays only the color of the surface and none of the contours. This keeps you focused on the silhouette of the object. A strong silhouette is the hallmark of good design; the eye perceives the shape first before all other details. In evolutionary terms, this makes sense because the brain may only have a split second to decide whether an approaching creature is a friend, foe, or lunch.
The Move Elastic Brush
Earlier in the chapter you were familiarized with the Move brush, which works well for shaping digital clay. The Move Elastic brush is a variation of the Move brush, but it is designed to help minimize polygon stretching. In this example, you’ll use the Move Elastic brush to shape the dragon’s head:
1. Set the draw size to around 100. Remember that draw size is relative to the size of the object on the canvas so an exact value is not crucial. Just make it large enough to grab a sizeable chunk of digital clay.
2. Click the sculpting brush icon at the top of the left palette. Type m and then e to select the Move Elastic brush.
3. You should be looking at the front of the PolySphere. You’ll know this is true if you can see two dots indicating that the brush is mirrored along the x-axis. Use the brush to pull some of the PolySphere out from the center.
You may notice that the PolySphere’s reaction to the Move Elastic brush is slightly different than its reaction to the Move brush. This is because the PolySphere adjusts its topology automatically as you use the Move Elastic brush. It is updating automatically to minimize polygon stretching. This may appear as a slight jittering while you use the brush, but don’t worry. It’s not a bug; it’s is just the mesh adjusting itself while you work.
4. As you pull outward from the center, try reversing direction—push back in toward the center without letting go. This creates a taper in the pulled section. Experiment pushing and pulling to get a sense of how the PolySphere responds to the Move Elastic brush (see Figure 3-31).
Figure 3-31: Pull out from the center using the Move Elastic brush (left image). Push back in without letting go to create a tapering in the surface (right image).
5. Right-click drag on the canvas to the right. Hold down the Shift key as you drag to snap to the side view. Experiment with shapes as you work—elongate the PolySphere in the side view to try to create something that looks dragonlike. Figure 3-32 shows how I developed the initial shape of my dragon head.
Figure 3-32: The head of the dragon is shaped from the side view.
6. Right-click drag on the canvas to rotate to a top view and continue to shape.
7. After a few moments, you should get something fairly interesting. At this point, go to the material fly-out library on the left shelf and choose the BasicMaterial (see Figure 3-33).
Figure 3-33: Choose the BasicMaterial from the material fly-out library.
Now you can see how the shape looks in three dimensions. Chances are it will look a little stretched, but that’s okay; you’re still working out the shape.
8. Hold down the Shift key to activate the Smooth brush. While you’re holding down the Shift key, set the Z Intensity slider to 20.
9. Hold down the Shift key and brush over the stretched portions to smooth the surface.
10. Continue to shape the surface, alternating between the Move Elastic brush and Smooth brush (see Figure 3-34).
11. As you use the Move Elastic brush, move your brush strokes back and forth to play with interesting shapes. You’ll find that you can create interesting contours in the surface that would be difficult to achieve with the regular Move brush.
Figure 3-34: Continue to shape the surface using the Move Elastic and Smooth brushes.
Use Move Elastic on Low-Density Meshes
Due to the fact that ZBrush is constantly updating the mesh as you use the Move Elastic brush, it is best suited for working on low-density meshes—meshes with 25,000 or fewer polygons. Using Move Elastic on meshes higher than 25,000 will cause the brush to behave more like the regular Move brush. ZBrush has built a polygon limit into the Move Elastic brush to prevent the software from slowing down too much while working on high-density meshes. You can raise the limit by increasing the Elasticity Auto Off slider in the Brush palette, but it’s a better idea to leave the limit set at its default value of 25 (meaning 25,000) and use the brush on lower subdivisions of the model.
12. Be sure to rotate to see the bottom of the mesh. You can pull the jaw out by dragging the polygons at the bottom of the PolySphere forward (see Figure 3-35).
Figure 3-35: From the bottom view, the jaw is created by pulling the bottom of the mesh toward the right.
13. Continue to shape the head from every angle. Pull and push and then smooth to even out the topology. Adjust the draw size as needed to create different details, but try to work in broad strokes. You are just roughing out the overall size of the head. Don’t worry about small details; the goal at this point is not a perfect dragon head, but something interesting that you feel you can work with.
If you can build personality into the dragon at this early, low-polygon stage, your final design will be much more successful. Keep your mind open to possibilities. Is your dragon fierce? Comical? Intelligent? What can you add to your design to make the dragon more or less terrifying?
14. When you arrive at a shape you like, use the File menu to save the file as dragon_v02.ZPR (see Figure 3-36).
Figure 3-36: The basic shape of the dragon head from the top, side, front, and perspective view
You may want to create several versions of the dragon head and decide which one you like best. In Figure 3-37 are a few variations I created using these same techniques. Avoid detail. In some cases it can be difficult to know when to stop. Always save when you come up with something you like. The dragon head I created can be found in the Chapter 3 folder of the DVD that comes with this book. I’ve included the alternate dragon heads as well.
Figure 3-37: Alternate versions of the dragon head are quickly realized using the Move Elastic and Smooth brushes.
The Move Topological Brush
The Move Topological brush can be used to shape the lower jaw of the dragon’s head without disturbing the shape of the upper lip. This is because, rather than affect the polygons within the overall area of the brush tip, the Move Topological brush makes a calculation to see how the polygons are connected through shared vertices and affects only those that have a connection. Even though the upper lip may be close to the lower in 3D space, the polygons of the upper lip are topologically far away from the upper lip because they have been pulled out from another part of the surface, and thus they are not affected by the brush.
This brush comes in very handy for adjusting lips, eyelids, fingertips, and other tight spots that might be difficult to sculpt with the regular Move brush. Follow these steps to shape the lower jaw:
1. Continue with your own dragon head or use the Open button in the File palette to load the dragon_v02.ZPR project. This project can be found in the Chapter 3 folder on the DVD that comes with this book.
2. On the left shelf, open the sculpting brush fly-out library and type m and g to select the Move Topological brush.
3. Rotate the view of the dragon head so that you can see the lower jaw.
4. Press Shift+D repeatedly until the mesh is set to the lowest subdivision level.
5. Increase the draw size to around 80 so that it’s large enough to grab a fair amount of digital clay.
6. Make sure symmetry is still active.
7. Pull the polygons on the bottom of the lower jaw downward to add some volume. Dragons should have powerful jaws, so you may want to thicken the jaw a fair amount.
8. While you pull at the surface, you’ll want to smooth it out as well by holding down the Shift key while brushing over the surface.
9. Feel free to shape other parts of the head as you work as well. Figure 3-38 shows how I used the Move Topological brush to increase the size of the lower jaw.
Smooth Brush Z Intensity
When working with a mesh set to a low subdivision level, you’ll want to lower the Z intensity of the Smooth brush; otherwise, you may find that it’s so strong that the shape of the model becomes quickly obliterated. To do this, hold down the Shift key and lower the Z Intensity setting.
ZBrush also has a Move Topological Elastic brush, which combines the properties of the Move Elastic brush with the Move Topological brush.
10. When you are happy with the overall shape of the dragon’s head, use the Save As button in the File palette to save the project as dragonsHead_v03.ZPR.
Figure 3-38: The Move Topological brush allows you to shape the lower jaw without affecting the upper lip.
Refine the Shape of the Dragon’s Head
Once you have established a basic shape using the Move and Smooth brushes, you can start to refine it using other types of sculpting brushes.
The Clay Brush
The Clay brushes work well for both building areas up and scraping other areas away. Clay brushes use an algorithm that has a stronger effect on the recesses of a surface than on the more level areas. This makes it feel as if you’re wedging clay into the surface, making the brushes feel very natural.
Brush Bases
The sculpting brush presets listed in the sculpting brush fly-out library are all variations on a few base brush types. For example Clay, Clay Line, Clay Tubes, Rake, and Form brushes are just a few of the presets that use the Clay brush as a base. When you hold the mouse pointer over the icon for a preset, a little preview pops up. At the bottom of the preview the Base Type listing tells you what that particular preset is based on. In Chapter 7, you’ll learn more about creating your own brush presets from a base type.
In this exercise you will use the Clay brush to rough out the forms of the head. At this point you should still be thinking of the overall shape of the head and not the details.
1. Continue with your own dragon head or use the Open button in the File palette to load the dragon_v03.ZPR project. This project can be found in the Chapter 3 folder of the DVD that comes with this book.
2. On the left shelf, open the sculpting brush fly-out library and type c and then a to select the Clay brush.
3. The Clay brush works best when used on a mesh at a higher subdivision level. Press the D hotkey two or three times to set the mesh to the highest subdivision level. Another way to do this is to open the Geometry subpalette of the Tool palette and set the SDiv slider to the highest level. On my version of the mesh, this is level 3.
4. Press the Ctrl+D hotkey to divide the mesh again. This adds another SDiv level above the highest one. In my example model, this adds a fourth level of subdivision. At SDiv 4, the mesh now has 98,304 polygons.
5. Set the draw size to around 20 or 30 and use the Clay brush to add form to the dragon’s head (see Figure 3-39). At this point, you shouldn’t worry about detail. Instead, try to refine the forms you created with the Move brushes.
6. Remember to hold the Alt hotkey when you want the Clay brush to dig into the model. Use the Shift hotkey to smooth the surface while you work. Repeated strokes over the surface will help you discover interesting shapes for the head.
7. You may want to increase the Z intensity of the Smooth brush when working at higher subdivision levels.
Keep your strokes fast and fluid while you work at this stage, kind of like sketching. Try to figure out where you want to place details such as eye sockets and nostrils.
Figure 3-39: The Clay brush is used to refine the shape of the head.
Often when I’m using this approach to sculpting, I find that some areas get too thin or flattened. When this happens, I switch to a lower SDiv level, smooth the area with the Smooth brush, and then use the Inflate brush to add volume to that area. Once the problem spot is repaired, I go back to a higher SDiv level and continue working with the Clay brush.
The Clay Build Up Brush
The Clay Build Up brush is a variation of the Clay brush. It has a few differences in the settings, which give it a slightly different feel. One notable difference is that an alpha texture is applied to the Clay Build Up brush.
Backface Masking
You can have problems with the brushes when sculpting thin areas of a surface, resulting in stretched polygons on the opposite side, as shown here.
Here are the steps to take to help alleviate this problem:
1. While the Clay brush is active, open the Brush palette and expand the Automasking subpalette.
2. Turn on Backface Masking.
You can use the BackMaskInt Intensity slider to adjust the amount of masking applied to the brush. In some cases if the BackMaskInt Intensity setting is too high, it may cause the brush to be ineffective when sculpting the surface. In most situations the best course of action is to take care when using any of the clay-type brushes on the thin parts of a model. Rotate the view of the model frequently as you work to make sure that polygons are not being stretched or mangled on the opposite side.
An alpha texture is simply a grayscale image (an image with no colors) that the brush uses to control the shape of the brush tip. Alpha textures have many uses and applications throughout ZBrush, but the most common use is as a modifier for brush tips. Let’s take a look at how you can use this brush to continue to shape the dragon’s head:
1. First, this is a good point to add another level of subdivision to the surface. Open the Geometry subpalette of the Tool palette and make sure the SDiv slider is at the highest possible level. On my dragon model, this is level 4 (see Figure 3-40).
Figure 3-40: The SDiv slider in the Geometry subpalette of the Tool palette is set to level 4.
2. Press the Divide button to add a fifth SDiv level (hotkey = Ctrl+D).
3. Open the sculpting brush fly-out library and press c and then b to select the Clay Build Up brush.
Take a look at the shelf on the left. You’ll see that a white square appears in the BrushAlpha button below the Stroke Type button (which currently shows the Freehand stroke) (Figure 3-41). This white square determines the shape of the brush tip on the surface.
Figure 3-41: A square-shaped alpha is applied to the Clay Build Up brush. This is indicated in the alpha icon on the left shelf.
4. Sculpt across the surface of the dragon head. Use the brush to build up the form in areas as you refine the shape. Remember to hold down the Alt key when you want to dig into the surface.
5. Hold down the Shift key to smooth the strokes as you work. Again, work in a sketching-like fashion, don’t worry too much about precision at this point (see Figure 3-42).
You can also try to experiment with the Clay Tubes, Form, Inflate, and Form Soft brushes to work out the overall shape of the head.
6. Once you have a shape that you think is looking sufficiently fearsome and dragonlike, use the Save As button in the File palette to save the file as dragon_v04.ZPR.
Figure 3-42: The Clay Build Up brush add layers of clay to the surface, which helps to define the forms.
Stroke Types
There are six stroke types that you can choose from for your sculpting brush. They are found in the stroke type fly-out library on the left shelf. Each stroke type changes the way the brush applies a stroke to the surface of the mesh. The Modifier sliders at the bottom of the stroke type fly-out library changes the behavior of each stroke type preset.
You can choose from the following stroke types:
Dots As you drag across the surface, the Dots stroke type creates multiple instances of the brush tip in a line. These instances are blended together to create what appears to be a smooth stroke. Increasing the Mouse Average (Mouse Avg) slider at the bottom of the stroke type fly-out library creates a smoother stroke. In the following image, a circular alpha is applied to the stroke to make the behavior of the Dots stroke type more obvious.
DragRect Instead of drawing a line, the DragRect stroke type lets you pull out an instance of the brush tip on the surface. As you drag out, you’ll see the mark created on the surface grow in size and in intensity, starting from the point where you first touch the surface. If you the drag back toward the center of the stroke, you can resize and set the orientation of the stroke. Once you are satisfied with the stroke’s placement, you can let go and the mark is made permanent. The DragRect stroke type is very useful when an alpha is applied to the stroke. In the bottom image on the previous page, the star-shaped alpha is used. It’s a great technique for adding details to a surface.
FreeHand This is just like the Dots stroke type, but there is a higher degree of blending between the instances of the brush tip on the surface, creating a very smooth stroke. This stroke can cause ZBrush to slow down a little when used on meshes with a high number of polygons.
Color Spray The Color Spray stroke type creates multiple instances of the brush tip spread out on the surface. You can increase the amount of variation in size of the instances by increasing the Scale slider in the modifiers at the bottom of the stroke type fly-out library.
When you use this stroke type on a brush that paints colors on the surface of the mesh, you can use the Color slider in the stroke type modifiers. This increases variation in the hue of the color applied with each instance of the stroke. Painting models is covered in Chapter 8, “Polypainting and Spotlight.”
Increasing the value of the Placement slider can increase the variation in distance from the center of the brush tip for each mark made by the Color Spray stroke type. Density of the marks is controlled using the Flow slider. In the following image, the star-shaped alpha is applied to a brush that uses the Color Spray stroke type. Color painting (known as polypainting) is not enabled for the mesh in this image; just Z Intensity so you can see how the surface is changed using this stroke type.
Spray This type is just like Color Spray except the that Color slider modifies the variation in color intensity of each mark made by the brush tip instead of the color hue.
DragDot This stroke type creates a single instance of the brush tip on the stroke. You can precisely place the mark the instance creates by dragging on the surface. Let go to make the mark permanent. The size of the mark is determined by the Draw Size setting.
The Creative Process
Designing forms in ZBrush, much like in mediums such as clay sculpture and sketching with a pencil, is not necessarily a linear process. The joy of ZBrush is that it lets you explore as you go. While working on models like the dragon head used in this exercise, I like to play with ideas. Many of the decisions you make can be changed later on or developed into different ideas as you work.
Masking protects a specified part of the mesh as you make changes. Masks give you more precise control over the mesh, and there are a number of ways to create masks. Masks are created using the masking pen, which is activated when you hold down the Ctrl key while the Draw button is active on the top shelf.
Mask Controls
In this exercise you’ll use masking to control which parts of the dragon’s head model can be edited with the brushes.
1. Continue with the file from the previous section or open the dragon_v04.ZPR project from the chapter 3 folder on the DVD that comes with this book.
2. Open the sculpting brush fly-out library on the left shelf and press s and then t to choose the standard brush.
3. Make sure symmetry is activated along the x-axis. If you rotate the view of the head to the top, front, or bottom, you should see two red dots as you hold the brush tip over the mesh. This means symmetry is on. If you don’t see two dots, press the X hotkey to turn symmetry on.
4. Hold down the Ctrl key and brush along the bottom of the head around the bottom of the jaw, as shown in Figure 3-43. The masked area appears as a dark gray color on the surface.
5. Release the Ctrl key and try painting on the dark area with the sculpting brush. Nothing happens. Try painting on the white areas and you’ll see that the surface is raised under the brush just as you would expect using the Standard brush. The darker areas are protected from the brush.
Figure 3-43: A mask is painted on the bottom of the surface, indicated by the dark gray area.
Figure 3-44: Pressing the Ctrl key activates the MaskPen brush.
When you press the Ctrl key while the Draw button is on in the top shelf, you activate the MaskPen brush. As you hold down the Ctrl key, note that the brush icon on the left shelf displays the MaskPen brush (see Figure 3-44).
6. Undo any changes you made with the Standard brush.
Figure 3-45: The mask controls are found in the Masking subpalette of the Geometry palette.
7. In the Tool palette, expand the Masking subpalette (see Figure 3-45). There are a number of controls here for changing the behavior of the mask as well as for creating different types of masks. Let’s look at some of the more frequently used controls.
ViewMask (hotkey = Ctrl+H) enables the visibility of the mask—the dark area on the surface. If this button is off, the mask will not be visible but it will still prevent changes from being made to the masked area of the surface. Sometimes the dark area of the mask can be distracting while you work on the surface, so ZBrush gives you the option of turning mask visibility off. If you ever encounter a situation in which it seems as if a sculpting brush is not working properly, double-check to see if the ViewMask button is off. It may be that you have accidentally applied a mask that you can’t see.
Inverse (hotkey = Ctrl+I) swaps the masked and unmasked parts of the surface so that the masked parts become unmasked and the unmasked parts become masked (see Figure 3-46). You can also invert the mask by holding the Ctrl key and clicking in a blank part of the canvas.
Figure 3-46: Inverting the mask swaps the masked and unmasked portion of a mesh.
Clear (hotkey = Ctrl+Shift+A) removes all masks from the surface. You can also clear the mask by holding down the Ctrl key while dragging on a blank part of the canvas. When you release the brush, all masks will be cleared.
MaskAll (hotkey = Ctrl+A) applies a mask to the whole surface. You can also hold down the Ctrl key and click on a blank part of the canvas to mask everything, provided nothing is masked already.
BlurMask blurs the edges of the mask. The mask is still present but not as intense along the blurred edges. Another way to blur the mask is to Ctrl+tap on the masked area (see the left image in Figure 3-47).
SharpenMask sharpens the edges of the mask, making them more defined. Another way to sharpen the mask is to Ctrl+Alt+tap on the masked area (see the right image in Figure 3-47).
Figure 3-47: The edges of the mask can be blurred (left image) or sharpened (right image).
Hold the Ctrl+Alt keys together to erase part of the mask.
Figure 3-48: A low-intensity mask is painted on top of a higher intensity mask.
Toward the bottom of the Masking subpalette you’ll see a slider labeled Intens. This controls the intensity of the mask. The value of this slider is applied to the next mask painted on the surface; it does not affect any masks currently applied to the surface. If you set this to 50, the next mask you create will be at half the normal strength. This means that the surface will still be affected by changes you make with the sculpting brushes but only at half strength.
Next to the Intens slider, you’ll see a slider labeled Blend. This controls how the next mask you create is blended with any masks currently applied to the surface. At 100, new masks will overwrite existing masks (see Figure 3-48), and at lower values they will be blended. At 0, new masks will not affect any masks painted on the surface.
8. Press Ctrl+I to invert the mask applied to the dragon’s head.
9. Hold down the Ctrl key and tap on the masked portion of the dragon’s head three times to add a blur to the edges of the mask. Each time you tap on the masked area, ZBrush increases the blurring of the mask’s edge.
10. Open the brush fly-out library, and press m and then e to choose the Move Elastic brush. Use the brush to pull the area under the jaw downward away from the top of the dragon’s head. This will give the dragon more of a throat below the jaw (see Figure 3-49).
11. Remember that if you want to smooth the surface while you work, just hold down the Shift key and paint over the surface.
12. Use the Save As button in the File menu to save the file as dragon_v05.ZPR.
Figure 3-49: The unmasked portion of the dragon’s head is pulled downward to create a throat.
MaskPen Stroke Types
The MaskPen brush can use all of the stroke types that a regular sculpting brush uses and a few extra. To change the MaskPen brush’s stroke type, hold down the Ctrl key and then open the stroke type fly-out library and click one of the stroke type icons.
You can use alphas with the MaskPen brush, and when you use the Color Spray stroke type, the variation in color varies the intensity of the mask. In the following image, a mask was created when a circular alpha was applied to the MaskPen brush while using the Color Spray stroke type.
The following image shows the additional stroke types available for the masking pen.
When you choose the Rect stoke type, you can use the MaskPen brush to define a rectangular-shaped area to be masked. As you hold the brush down and drag, you can set the size of the masked area. The center of the mask is indicated by a white plus sign. If you want to reposition the mask, let go of the Ctrl key and hold down the spacebar. As long as you hold down the spacebar, you can position the rectangular mask anywhere over the surface. Let go of the brush to apply the mask to the surface.
At the bottom of the stroke type fly-out library there are two options: Square and Center. When Square is enabled, the masked area is always a perfect square. When the Center option is enabled, the center of the masked area is determined by wherever you initially click on the canvas. As you continue to drag, the mask is sized relative to the center. When Center is off, dragging out a corner of the rectangular area creates the mask.
If you create a mask on a side of an object, the mask goes all the way through the surface and masks the opposite side as well. Using symmetry together with the Rect stroke type is a great way to create intricate designs with your mask.
The Circle stroke type behaves just like the Rect stroke type except that the selected area is an oval and not a rectangle. If you activate the Square option in the modifiers, the masked area will always be a perfect circle.
Use the Curve stroke type to define a masked area by drawing a curve on the canvas. While holding down the Ctrl button, click on the canvas to start the curve. You can release the Ctrl button while drawing out the initial line. Each time you want to add a point in the curve to change directions, just tap the Alt key. The display on the canvas shows that one side of the curve is shaded. This indicates which side of the line will become the masked area. Hold down the spacebar while dragging on the canvas to reposition the curve. To apply the mask, just let go of the brush, either by releasing the left mouse button or by lifting the stylus of your digital tablet.
The shape you make with the curve can’t be a closed shape, and the curve can’t double-back on itself. This will confuse ZBrush and the mask you get will not be what you expect.
To make a hard corner in the curve, double-tap the Alt key.
The Lasso stroke type lets you define a free-form area for the mask by drawing on the canvas while holding down the Ctrl key. You have more freedom to create closed shapes than you do with the Curve stroke type but not as much precise control. Hold down the spacebar to reposition the masking area.
The polygons of a mesh can be organized into groups known as polygroups. This is useful when you need to isolate a particular part of a surface area over and over again. Rather than try to create the same mask every time you need to work on one part of your mesh, which can be very tricky on complex surfaces, you can create a polygroup, which is saved with the mesh. The grouped area of the mesh can be isolated for masking and other operations as often as you like for as long as you keep the polygroup.
Figure 3-50: The polygons of a mesh have been arranged into polygroups indicated by the colored regions.
Polygroups are displayed as colors applied to the polygons. You can see these colors only when the PolyF button is enabled on the right shelf (hotkey = Shift+F). The color of the polygons do not affect any colors painted on the surface. They just provide a visual indication of how the polygons of the mesh have been arranged into groups (see Figure 3-50).
An individual polygon can’t be a member of more than one group at a time. Polygroups are saved as part of the mesh. You can rearrange the mesh into different polygroups as often as you like. You can create a polygroup when the mesh is at any subdivision level, but results are more predictable when you create polygroups at the lowest subdivision. If you create a polygroup at a high subdivision level and then move the SDiv slider down to a lower level, the polygroups can get a little confused, which may alter the membership of the polygons in the polygroup.
There are a number of ways to create polygroups. The following sections cover the more common techniques for arranging a mesh into polygroups. Before creating polygroups, it is important to understand how to select the polygons of a mesh in ZBrush (Figure 3-51).
Select Polygons
Figure 3-51: Turn on the Pt Sel button in the Transform palette to make polygon selection easier.
To select the polygons of a mesh, press and hold the Ctrl+Shift key combination and drag over part of the surface. This activates the selection brush. The selected polygons remain visible while unselected polygons are hidden. Here is a short example that demonstrates how this is done:
1. Place the mouse pointer toward the bottom of the ZBrush interface to open Light Box. Select the Project heading and double-click DefaultSphere to open the DefaultSphere project. This project has a gray PolySphere in Edit mode ready for sculpting.
2. In the color picker on the left shelf, set the color to white. This changes the color of the PolySphere to white, making it easier to see what’s going on while you work.
3. Make sure symmetry is enabled for the PolySphere; it should be on already.
4. On the right shelf, turn off the Persp button.
5. In the Transform palette, turn on Pt Sel. This enables point selection, which means that if a vertex of a polygon falls within the selection area, the entire polygon will be selected. I find this makes selecting polygons much easier.
6. Rotate the view of the PolySphere while holding down the Shift key so that you’re looking at it straight on from the front. If you see two red dots on the mesh when you hold the mouse pointer over the mesh, you’ll know you’re looking at the front.
7. Hold down Ctrl+Shift. Notice that the sculpting brush icon on the right shelf turns into the SelectRect selection brush (see Figure 3-52). This is one of the two selection brush presets.
Figure 3-52: The SelectRect brush is activated by holding the Ctrl+Shift key combination.
8. Drag across the surface of the PolySphere. You’ll see a large green rectangle appear. Drag so that you are covering about one-third of the side of the PolySphere (left image in Figure 3-53).
9. Let go by releasing the left mouse button or lift your stylus from the surface of the digital tablet. You’ll see two sides of the PolySphere left on the canvas; the center has disappeared (right image in Figure 3-53).
The two sides are visible because symmetry is enabled for the selection brush. This means that the area on the opposite side of the PolySphere has been selected as well. The polygons in the center have not been deleted; they are just invisible for the moment.
10. As you rotate the view, you’ll notice that the back side of the polygons are not visible (left image in Figure 3-54). In the Tool palette, scroll down to the Display Properties subpalette. Click Double to enable double-sided display. Now you should be able to see the back side of the polygons (right image in Figure 3-54).
Figure 3-53: The area behind the green rectangle is selected using the SelectRect brush (left image). The visible portion that is left after releasing the brush is considered selected. Because symmetry is enabled, the selection is mirrored to the opposite side (right image).
11. To restore the visibility of the PolySphere, hold down Ctrl+Shift and click on a blank part of the canvas.
12. Hold down Ctrl+Shift again and drag across the surface to select a part of the side of the surface; another green rectangle appears. Before releasing the brush, let go of the Ctrl+Shift keys and press the Alt key. The rectangle now turns red (left image in Figure 3-55).
13. Let go of the brush, and this time, any part of the mesh within the area defined by the selection is hidden (right image in Figure 3-55).
14. Ctrl+Shift+click on the visible part of the surface; this inverts the visibility, unhiding the hidden parts and hiding the visible parts.
15. Hold down Ctrl+Shift and click on a blank part of the canvas to restore the visibility of the whole PolySphere mesh.
Figure 3-54: The backsides of the polygons are not visible unless the Double button in the Display Properties subpalette of the Tool palette is enabled.
Figure 3-55: The Alt key is used to invert the selection (left image) so that all polygons within the selection area are hidden (right image).
Tips for Working with the Selection Brush
While you’re holding down the Ctrl+Shift key combination, the Select brush is activated. Like the MaskPen brush, this brush type has some special properties.
The Select brush is always mapped to the Ctrl+Shift key combination. While holding down Ctrl+Shift, you can change the properties of the brush. For example, you can choose an alpha texture from the alpha fly-out library on the left shelf. This will cause the shape of the selected area to be determined by the shape of the alpha.
There are four stroke types that can be applied to the Select brush: Rect, Circle, Curve, and Lasso. They behave the same way with the select brush as they do with the MaskPen brush. See the sidebar titled “MaskPen Stroke Types” earlier in the chapter for more information on these stroke types.
In the sculpting brush fly-out library, you’ll see the SelectLasso and SelectRect brush types. Choosing one of these brush types automatically maps one or the other to the Ctrl+Shift key combination. The only difference between the two selection brush presets is that one has the Lasso stroke type applied and the other has the Rect stroke type applied. You can change the stroke type by choosing from the stroke type fly-out library while holding down Ctrl+Shift.
If you want to reposition the selection, let go of the Ctrl+Shift keys without releasing the brush, and then hold down the spacebar and drag the selection to another part of the canvas.
If you want to permanently delete part of a mesh, use the selection brush to hide the area you want to remove and then press the DelHidden button in the Geometry subpalette of the Tool palette. This can be done only when the model is at the lowest subdivision level.
If you’re using the SelectLasso brush, be careful not to Ctrl+Shift+click on a polygon edge. This hides all the polygons along the row perpendicular to the edge. This can be helpful sometimes, but it can also start to drive you crazy after a while. If this keeps happening, try switching to another stroke type for the selection brush.
Create a Polygroup from a Selection
Once you have a handle on how you can select polygons using the selection brush, you can easily create polygroups:
1. With the DefaultSphere project loaded, press the Shift+D hotkey combination twice to move to the lowest subdivision level.
2. Turn on the PolyF button on the right shelf to display the wire frame on the mesh (hotkey = Shift+F).
3. Press the X hotkey to toggle symmetry off.
Figure 3-56: The Group Visible button creates a polygroup for all visible polygons.
4. Hold down Ctrl+Shift to activate the selection brush. Drag a green rectangle over part of the surface and then let go. The unselected part of the surface disappears.
5. In the Polygroup subpalette of the Tool palette, click Group Visible (see Figure 3-56). You’ll see the polygons change color. You have just created a polygroup for the visible polygons.
Group Visible creates a polygroup for all polygons visible on the canvas regardless of whether they are already in a polygroup. The color applied to the polygroup is visible only when PolyF is on and does not affect the color of the model. The colors chosen for the polygroups are selected at random by ZBrush. If you don’t like the color of the polygroup, just press Group Visible again until you find a color you do like.
Figure 3-57: The polygons of the Polysphere have been arranged into two polygroups.
6. Hold down Ctrl+Shift and click on the canvas to unhide the rest of the PolySphere. The color of the polygons indicate that the polygons of the mesh have been arranged into two polygroups (see Figure 3-57).
7. Hold down Ctrl+Shift and click the center of one of the polygons within the polygroup. This will hide all parts of the mesh that are not in the polygroup.
8. Hold down Ctrl+Shift and drag out a selection rectangle over half of the remaining visible polygons. This will hide part of the polygroup.
9. In the Polygroup subpalette of the Tool palette, click Group Visible again. The visible polygons change color.
10. Hold down Ctrl+Shift and click on a blank part of the canvas to restore the visibility of the entire mesh. You should see that the PolySphere now has three polygroups, indicated by the colors of the mesh (see Figure 3-58).
Figure 3-58: The polygons of the PolySphere have been arranged into three polygroups.
Tips on Working with Polygroups
Here are some tips for working with polygroups:
To hide everything outside of the polygroup, Ctrl+Shift+click the center of a polygon within the group.
To invert the visibility of the mesh, Ctrl+Shift+click again the center of one of the polygons within the polygroup.
After inverting the visibility of a polygroup, each time you Ctrl+Shift+click a polygon within a polygroup, that polygroup will become hidden.
If you click a vertex shared by polygons in two or three adjacent polygroups, everything outside of those polygroups will be hidden.
Create a Polygroup from a Mask
You can create a polygroup from any masked area. This means you can paint a mask on the surface and then convert the painted area into a polygroup, which gives you more control over how you create polygroups.
This should be done at the lowest subdivision level. It’s tempting to paint an intricate mask at the highest subdivision level and then convert the mask into a polygroup. This will work, but if you move the SDiv slider down to a lower level and then back up again, the polygroup will be rearranged.
To create a polygroup from a mask, follow these steps:
1. Create a mask on the surface using any of the MaskPen brush’s stroke types and settings.
2. In the Geometry palette, expand the Polygroups subpalette.
3. Click the From Masking button to create the polygroup.
4. Turn on the PolyF button to see the mask (see Figure 3-59).
Figure 3-59: A polygroup is created from a mask painted on the surface of a mesh.
Create a Polygroup for the Dragon’s Jaw
Some areas of a mesh can be hard to select directly. In this example, you’ll learn how to creatively apply section techniques to create a polygroup for the dragon’s jaw:
1. Continue with your own version of the dragon head or use the File palette to open the dragon_v05.ZPR project from the chapter 3 folder on the DVD.
2. Expand the Geometry subpalette of the Tool palette and set the SDiv slider to 1.
3. Rotate the view of the dragon’s head so that you can see it from the side.
4. Make sure the Pt Sel button in the Transform palette is activated. In the Tool palette, make sure Double is activated in the Display Properties subpalette.
Figure 3-60: The SelectLasso brush is used to select the polygons on the front of the dragon’s chin.
5. Scale the view of the mesh up so that you can clearly see the side of the chin.
6. Open the sculpting brush fly-out library. Press s and then l to select the Select Lasso brush. You’ll see a warning indicating that this brush will be mapped to the Ctrl+Shift hotkey combination. Press the OK button.
7. Hold down Ctrl+Shift and draw a lasso selection around a few of the polygons at the end of the chin. You want to select just part of the front of the jaw. This may take a couple of tries (see Figure 3-60).
8. Rotate the view of the model; you should see just two polygons. If more are visible, use the selection brush to hide the rest (see the left image in Figure 3-61).
9. In the Visibility subpalette of the Tool Palette, press the Grow button (hotkey = Ctrl+Shift+X). This expands the visibility of the polygons by one row (see the center image in Figure 3-61).
10. Press the Grow button several times to gradually reveal the polygons of the jaw. The idea is to select the parts of the jaw on the inside that are hard to reach using other selection techniques (see the right image in Figure 3-61).
Figure 3-61: The visibility of the polygons of the chin is expanded by repeatedly pressing the Grow button.
11. If you select too much, you can use the Shrink button in the Visibility subpalette of the Tool palette to reduce the size of the selection.
12. Once you’re happy with your selection, press the Ctrl+A hotkey combination to mask all of the visible polygons.
13. Hold down Ctrl+Shift and click on a blank part of the canvas to unhide the rest of the mesh.
14. Press the Ctrl key to activate the MaskPen brush. While holding down the Ctrl key, set the stroke type to Freehand.
15. Hold down the Ctrl key and paint on the surface of the model to add to the mask; the idea is to extend the mask to the rest of the jaw (see Figure 3-62).
Remember that you can hold down Ctrl+Alt and paint on the surface to erase parts of the mesh if you need to. Rotate the view of the model as you edit the mask, and make sure the polygons on the bottom and at the back of the jaw are masked as well.
16. Once you’re happy with the mask, expand the Polygroup subpalette of the Tool palette and press the From Masking button to create a polygroup from the masked portion.
17. Make sure the PolyF button is activated on the right shelf so that you can see the colors of the polygroup. The polygons of the jaw should be a different color than the rest of the mesh, indicating the polygroup arrangement (see Figure 3-63).
It may take a couple tries to get the group right. You can always use the Undo button in the Edit palette (hotkey = Ctrl+Z) to undo the polygroup arrangement and try again. Just try not to remove the mask completely until you have the jaw grouped the way you want it to be.
18. Use the Save As button in the File menu to save the project as dragon_v06.ZPR.
Figure 3-62: The mask is expanded to the rest of the outside of the jaw using the MaskPen brush.
Figure 3-63: The mask is converted into a polygroup. Now the mesh is organized so that the jaw can easily be selected in the future.
Add Geometry with Edge Loops
Figure 3-64: The arrangement of polygons surrounding the mouth and each eye are referred to as edge loops.
As you are aware by now, the sculpting brushes do not add polygons to the mesh; they only move the existing polygons around. So how do you add new polygons to a mesh? This can be achieved with edge loops.
The term edge loops refers to a band of polygons that loop around a surface. A good example would be the polygons that go around a character’s lips or eye sockets. Figure 3-64 shows a simplified character that has edge loops around the area of the mouth and each eye socket.
When you create edge loops in ZBrush, polygons are added to the surface. You can use this as a way to extend part of the surface. In this example, you’ll add edge loops to the back of the dragon’s head to create part of the neck:
1. Continue with your own version of the dragon head or use the File palette to open the dragon_v06.ZPR project from the chapter 3 folder on the DVD.
2. Expand the Geometry subpalette of the Tool palette and set the SDiv slider to 1.
3. Press Ctrl+Shift+A to clear all masks applied to the surface.
4. Rotate the view of the dragon so that you can see the back of the head. Ctrl+Shift+click on the back of the head to isolate the visibility of the head; the jaw should become hidden.
5. From the sculpting brush fly-out library, choose the SelectLasso brush.
6. Hold down Ctrl+Shift and drag around the polygons on the back of the head to select them. Release the brush to hide the rest of the dragon’s head.
7. Continue to use the selection brush to pare down the visibility of the polygons on the back of the head so that it resembles what is shown in Figure 3-65.
Figure 3-65: The polygons on the back of the head are isolated.
Figure 3-66: The Edge Loop button is in the Geometry subpalette of the Tool palette
8. Rotate the view of the head and double-check that only the polygons on the back of the head are visible. It’s a good idea to make sure Double is activated in the Display Properties subpalette of the Tool palette. This ensures that you can easily see both sides of the polygons, making it easier to spot polygons that should be hidden.
9. When you are satisfied that only the polygons on the back of the head are visible, expand the Geometry subpalette of the Tool palette and click the Edge Loop button (see Figure 3-66). This adds an edge loop of polygons around the selected polygons. Note that the polygons of the edge loop are added to a new polygroup, indicated by the color coding (see Figure 3-67).
10. Open the sculpting brush fly-out library. Press m and then e to select the Move Elastic brush.
11. Use the Move Elastic brush to pull the polygons of the back of the head out to form part of a neck (see Figure 3-68).
12. Hold down the Shift key and paint over the polygons to smooth them out a little.
13. Hold down Ctrl+Shift and click on a blank part of the canvas to unhide the rest of the dragon’s head.
14. Hold down Ctrl+Shift and click on the polygons at the center of the back of the head to isolate their visibility.
15. Create another edge loop by clicking the Edge Loop button in the Geometry subpalette of the Tool palette.
16. Use the Move Elastic brush to pull these out as well.
17. Repeat this process until you have about four edge loops and the start of a neck coming out of the back of the dragon’s head.
18. Ctrl+Shift+click on a blank part of the canvas to unhide the whole mesh. Spend a few minutes using the Move Elastic and Smooth brushes to shape the neck and fix any problems with the back of the head (see Figure 3-69).
19. Once you are happy with the basic shape of the neck, use the selection brushes to isolate the polygons of the neck, and create a single polygroup for the neck using the Group Visible button. Arrange the polygons of the surface so that there are three groups: one for the head, one for the neck , and one for the jaw (see Figure 3-70).
20. Use the Save As button in the File palette to save the project as dragon_v07.ZPR.
Figure 3-67: An edge loop is created around the polygons on the back of the head.
Figure 3-68: The Move Elastic and Smooth brushes are used to pull the polygons out to create a neck.
Figure 3-69: After several edge loops are added, the head is unhidden and the neck is shaped and smoothed using the sculpting brushes.
Figure 3-70: The mesh is reorganized into three polygroups for the head, neck, and jaw.
Open the Dragon’s Jaw with Transpose
The Transpose control is a special mode of the Move, Rotate, and Scale buttons found on the top shelf. Using the Transpose control, you can pose the limbs of your sculpture as you work, twist a figure around, move individual pieces of a multipart object, and more. In this example, you’ll use the Transpose control to open the dragon’s jaw, making it easier to sculpt the inside of the mouth.
The Transpose Control
The Transpose control appears when you press the Move, Scale, or Rotate button on the top shelf while a mesh is in Edit mode. The controller itself looks like a line with three pairs of concentric circles (see Figure 3-71). One pair of circles is at the center and the other two are at either end of the line. The line that connects the three pairs of circles is known as the action line and it determines the central axis of the control.
Figure 3-71: The Transpose control looks like a line connecting three pairs of concentric circles.
Along the action line are tick marks that can be used as a guide to measure distances in ZBrush. You can adjust the distance between each of the marks using the settings in the Transpose Units subpalette of the Preferences palette.
The three pairs of circles along the action line are the handles. The outside circle of each pair is used to position the control, and the inside circle of each pair is used to pose the mesh. It takes a little practice, but after some experimentation, you’ll find that using the control becomes easy.
The following demonstrates how the Transpose control can be used to open the dragon’s jaw.
The first step is to create a mask on the surface that you want to pose. The mask should be carefully created; the Transpose control will alter any part of the surface that is not masked:
1. Continue with your own version of the dragon head or use the File palette to open the dragon_v07.ZPR project from the chapter 3 folder on the DVD.
2. Expand the Geometry subpalette of the Tool palette and set the SDiv slider to 2.
3. Press Ctrl+Shift+A to clear all masks applied to the surface.
4. Hold down the Shift key and smooth out any stretched or creased areas of the neck. Using the edge loop feature described in the previous section can add some creases to the surface (see Figure 3-72).
Figure 3-72: Creases in the neck at higher subdivision levels were created when the edge loops were added in the previous section (left image). They can be removed using the Smooth brush (right image).
5. Move up each level of subdivision and continue to smooth the surface of the neck at each SDiv level. Eventually the SDiv should be set to subdivision level 5.
6. Once you have the mesh at SDiv level 5, Ctrl+Shift+click on the jaw to isolate the visibility of the jaw polygroup.
7. Press Ctrl+A to mask the jaw.
8. Hold down Ctrl+Shift and click on a blank part of the canvas to unhide the entire mesh.
9. Press Ctrl+I to invert the mask.
10. Use the Mask brush with the Freehand stroke type and paint on the surface to clean up the mask. You want to make sure everything except the jaw is masked (see Figure 3-73).
11. Ctrl+click on the masked area of the surface a couple of times to blur the edges of the mask.
Figure 3-73: The head is masked except for the jaw. The mask is then edited using the MaskPen brush.
Once the surface has been carefully masked, the next step is to position the Transpose control. In this example, you want to use the handle of the control to rotate the jaw to an open position:
1. Rotate the view of the dragon’s head so that you are looking at it from the side. Hold the Shift key as you rotate the view so that it snaps to a side view.
2. On the top shelf, press the Rotate button (hotkey = R).
3. Drag on the surface to draw out the Transpose control. Drag from the largest area of the jaw at the back of the head toward the front of the chin. Drag all the way off the surface to a blank part of the canvas in front of the chin (see Figure 3-74).
Figure 3-74: The Transpose control is drawn on the surface of the mesh and extended past the front of the chin.
As you drag on the surface, the action line and the handles of the Transpose control appear. Notice that while you are dragging on the surface, the end of the transpose handle snaps to the polygons of the surface. This is meant to help you position the control.
If symmetry is activated on the mesh, you’ll see a second transpose control on the opposite side of the dragon’s head. This can be useful when posing parts of a symmetrical body such as arms and legs, but sometimes it can cause problems when posing parts of the body such as the head. The safest course of action when posing the jaw is to turn symmetry off.
4. In the Transform palette, make sure the Activate Symmetry button is off.
To position the Transpose control, drag on the outer circles of each handle. You want to place one end of the Transpose control at the pivot point of the jaw; you’ll have to figure out where that is on the side view of your version of the model. Usually it’s around the center of thickest part of the side of the jaw.
5. Hold the mouse pointer over the circle at the end of the action line nearest the pivot point of the jaw. You’ll see the inner circle of the handle displayed in red and the outer circle displayed in yellow. Click on the outer, yellow circle and move it to position that end of the Transpose control (left image in Figure 3-75).
6. If you want to move the entire control, click on the outer circle at the center of the action line. You can also do this by clicking and dragging on the parts of the line that are between the circular handles.
7. Click and drag on the outer circle on the end of the Transpose control that is in front of the chin to position this end of the Transpose control.
8. Rotate the view of the dragon’s head so that you can see the control from other angles. The handles of the control should be parallel to the dragon’s head. If it is at an angle, it may cause the rotation of the jaw to be off center. Remember to check the position of the Transpose control from all angles to ensure that the changes you make are accurate (see center and right images in Figure 3-75).
Figure 3-75: The Transpose control is positioned by dragging on the outer circle of the handles at either end. The position of the handle is checked by rotating the view of the mesh.
When you are satisfied with the position of the handle, you can use it to actually rotate the jaw:
1. Rotate the view of the mesh back to a side view. Hold the mouse pointer over the circular handle of the Transpose control that is in front of the chin. You’ll see the inner, red circle appear.
2. Click and drag on the inner, red circle; drag downward to open the jaw (left image in Figure 3-76).
Usually you’ll need to reposition parts of the mesh after you use the Transpose control to pose it. The trick to mastering the use of the Transpose control is patience and practice.
3. Click the Move button on the top shelf to switch to Move mode, or press the W hotkey.
4. Hold the mouse pointer over the circular handle at the middle of the action line. A white inner circle appears. Click and drag on this to move the jaw. Move it up a little to bring it closer to the head (center image in Figure 3-76).
5. Alternate using Move and Rotate to position the jaw. Rotate the view while you work to make sure the jaw is not rotated off center (right image in Figure 3-76).
6. Once you feel that the jaw is sufficiently open, use the Save As button in the File menu to save the project as dragon_v08.ZPR.
Clean Up The Dragon’s Head
You’ll almost always have to spend some time touching up the model after posing it with the Transpose control. This involves using the sculpting brushes to repair areas that have become stretched or squashed. In the case of the dragon, the polygons inside the mouth are stretched pretty badly, but it doesn’t take much work with the sculpting brushes to fix this:
1. Continue with your own version of the dragon head or use the File palette to open the dragon_v08.ZPR project from the chapter 3 folder on the DVD.
2. Press Ctrl+Shift+A to clear all masks applied to the surface.
3. Expand the Geometry subpalette of the Tool palette and set the SDiv slider to 5. Press the Divide button to add a sixth level of subdivision.
Figure 3-76: The jaw is opened using Transpose in Rotate mode (left image). It is then moved upward using Transpose in Move mode (center image). The changes are checked in other views of the mesh (right image).
Tips on Using Transpose
The behavior of the circular handles at each end of the Transpose control is different depending on whether you’re using the control to move, rotate, or scale the unmasked parts of the surface. The best way to get comfortable using Transpose is to practice. Open the SuperAverage man model in the Tool section of Light Box and experiment with different ways to pose the model. Remember to mask parts of the model that you do not want to move. Some models will be easier to pose at lower subdivision levels.
When in Move mode (hotkey = W), drag on the inner circle of the circular handles at each of the far ends of the control to stretch the surface. The circle at the opposite end from the one you are dragging is the pivot point for the stretching action. Drag on the center circle of the handle in the middle of the action line to move the entire unmasked portion.
When in Scale mode (hotkey = E), drag on the inner circle of handles at the ends to create a uniform scale, The circle at the opposite end from the one you are dragging is the pivot point for the scaling action. Drag on the center circle of the handle in the middle of the action line to create a nonuniform scale. The direction of the scaling is perpendicular to the angle of the action line.
When in Rotate mode (hotkey = R), drag on the inner circle of handles at the end to rotate the unmasked portion. The circle at the opposite end from the one you are dragging is the pivot point for the rotation. Drag on the center circle of the handle in the middle of the action line to rotate around the axis of the action line.
Hold down the Ctrl key and drag on the surface while the Transpose control is active to create a topological mask. This is a type of mask that follows the topology of the mesh based on the direction the tool is dragged. This can be useful for masking in tight areas such as the tips of fingers curled into a fist. It takes a little practice to get used to how topology masks are generated. When you release the Transpose control, the surface becomes masked and the edges of the mask are automatically blurred.
4. Select the Move brush from the sculpting brush fly-out library. Use the brush to pull the geometry on the inside of the mouth back toward the throat to form a cavity. Smooth the geometry as you work.
5. Try using the Inflate brush and the Form Soft brush to smooth the geometry inside the mouth. Hold down the Alt key while using these brushes so that the form is pushed inward (see Figure 3-77). Sometimes it’s faster and easier to use these brushes while the model is set to a lower SDiv level.
Chapter 7 will go into detail about how the sculpting brushes work, but feel free to experiment with trying out the different brush presets on your dragon’s head. Some of the brushes may appear to behave strangely or seem to do nothing at all. That’s okay. The mystery of these brushes will be revealed later in the book. Don’t let it bother you for the moment if something seems really odd; just make a mental note of which brushes you like and which seem very weird while you are experimenting with your project.
Figure 3-77: The inside of the throat is shaped using the Move, Inflate, Smooth, and Form Soft brushes.
Refine the Forms
Now that the basic shape of the head has been established, you can use the sculpting brushes to refine the forms. Don’t worry about details like scales and bumps just yet. There’s still a way to go in the next chapters before you get to that point. I sculpted my dragon head using the Move Elastic, Flatten, Move, Inflate, Clay Build Up, Form Soft, and Medium Polish brushes. You can open a movie I recorded of this sculpting session from the chapter movies folder on the DVD. The movie file is named dragonSculpt1.mov. Watching the movie is helpful because you’ll see how I experiment while I work. Figure 3-78 shows some of the stages of the model as I worked. Overall it took me about 40 minutes to refine the forms.
Figure 3-78: Using a variety of brushes, I shaped and refined the forms of the dragon’s head.
The Medium Polish (mPolish) brush uses the Polish algorithm, which is similar to how the Smooth brush works in that it removes lumpy spots on the surface, but unlike the Smooth brush, the Polish brushes will not remove hard edges. In fact, they can be used along an edge to help accentuate it. The Medium (mPolish) and Hard Polish (hPolish) brushes are excellent choices when you want to define a hard surface. Use them for armor, metal, or any type of hard surface. On my dragon head, I used the mPolish brush to remove the lumps created by the Clay Buildup and Form Soft brush.
I did not add teeth or eyes to the dragon. In Chapter 4, you’ll learn how to add parts to the dragon using subtools. You can open the example file named dragon_v9.ZPR from the chapter 3 folder on the DVD.