CHAPTER 8

Creating a Photo-Real Character

Photo-realistic characters are perhaps the most difficult to create. Because we see people every day, photo-realistic CG characters are judged by the highest of standards. That means during the creation phase reference images and maquettes should be followed meticulously.

True photo-realistic characters are typically reserved for pre-rendered film work. Of course, next generation consoles are able to deliver stunning characters, but they are still limited to what can be delivered in a real-time environment (that means thousands of polygons, perhaps tens of thousands). Photo-realistic characters of films can command millions of polygons. In fact, the x64-bit computers available today can handle characters upward of 20 million polygons or more, allowing artists to achieve truly amazing characters.

As I mentioned previously, my favorite anatomy website is http://www.3d.sk/. There are thousands of photos available ranging from modeling poses, to clothed humans, to action poses.

Before a model can be brought into ZBrush, the UV coordinates should be laid out. While ZBrush does have automatic UVs (gUV and aUV), Maya doesn’t work too well with them. Therefore, you should take some time to set your own UVs.

Tutorial: ZBrush Blocking

Just as we did during the blocking stage in Maya, it’s important to build detail slowly and shape the model as you work. This is where ZBrush really shines. ZBrush 3 has some incredible modeling tools available.

1. Open ZBrush, click Tool>Import and navigate to the .obj model. Click and drag in the work area to place the model in the scene.

2. Immediately press the "t"shortcut key to enter edit mode. This is important. If you try to do anything else, the model will be dropped to the canvas and will no longer be a 3D object.

3. You are currently looking at the lowest resolution of the mesh.

FIGURE 8-1   The tool in ZBrush.

4. In the Transform menu make sure Mirror Symmetry is on for the X axis. Because the character was modeled in Maya and mirrored on the X axis, it’s possible to work in a similar fashion in ZBrush.

FIGURE 8-2   Mirror options.

5. Use the Move, Scale, and Rotate buttons along the right side of the window to position the model for sculpting. Remember, if you need to zoom in on the model in ZBrush, you will usually use Scale. The Zoom button actually zooms the entire document and will cause artifacts. You can also rotate the model by LMB clicking and dragging a blank area of the canvas. The shortcut to move around the model is pressing ALT+LMB clicking and dragging in a blank area of the canvas.

Now that you are ready to begin blocking out the character, remember to hold off subdividing the mesh until absolutely necessary. Blocking out the mesh in ZBrush means defining the major muscle and bone masses. Do not try to add smaller details too early or you will have a hard time editing the mesh later.

1. Locate the major bone masses on your reference images. Because the skeleton is the framework of the body in real life, it is always a good idea to start there.

FIGURE 8-3   Bone landmarks.

2. After the bony areas are defined, sculpt the larger muscle masses.

FIGURE 8-4   Muscle masses.

3. When sculpting, you will mainly be using the Inflate, Standard, Smooth, and Move brushes. The Inflate brush is the best way to expand small sections like the fingers and toes. The Standard brush is good for general use. The Move brush is great for moving or "tweaking" the mesh. The Smooth brush will smooth out any undesired bumps or creases.

FIGURE 8-5   The Inflate brush.

4. If the brush is too large or the intensity is too high, adjust the Z Intensity and Draw Size respectively. The lower the value here, the smaller the effect will be.

FIGURE 8-6   Brush options.

5. If you need to deflate while using the Inflate brush press and hold the ALT key as you sculpt. This will temporarily enable the Zsub shortcut.

6. Likewise, if you need to smooth out any section, press the SHIFT key while sculpting to temporarily enable the smooth brush.

7. Continue sculpting until you have defined all of the main bony masses and large muscle landmarks.

Tutorial: Working with 3D Layers

3D Layers are a great feature in ZBrush. They allow you to add detail which can be turned on or off at anytime during the creation of the model. Think of these layers like the ones in a 2D program like Adobe Photoshop. You can add new detail to the layers without damaging your original model.

1. With your model loaded, click Tools>Layers>New. This will create a new 3D layer with your model. Rename this to Base layer.

2. Click Tools>Layers>New to create a second layer. This layer can contain new sculpting details without affecting the original. Any sculpting you do on this layer will be added to and blended with the main layer without damaging the original. You can even pose the model and switch between the posed and original versions by turning off the pose layer.

FIGURE 8-7   3D layers: the base layer.

FIGURE 8-8   3D layers: the pose layer.

Tutorial: Sculpting with Symmetry

Now that you have a pose layer, you can switch back to the original layer whenever you need to do any symmetrical sculpting. This works okay, but anytime you divide the mesh, you lose the ability to switch between the pose layers without first stepping down to the lower subdivision. This can be problematic when you are working with higher resolutions. A better option is to use Posable Symmetry.

1. Load your model that contains the pose layer.

FIGURE 8-9   Lost symmetry.

2. Click Transform>Activate Symmetry. Check X for the symmetry to mirror across the X axis.

3. Click Transform>Use Posable Symmetry. ZBrush will calculate the symmetry of the model. When sculpting with symmetry, the cursor will turn green.

FIGURE 8-10   Symmetry options.

The model will now have symmetry. Meaning you can sculpt with symmetry on a posed model. The cursor will turn green indicating you are using Posable Symmetry. If you move to a different division level, you will need to reapply the Use Posable Symmetry too.

FIGURE 8-11   Symmetry.

Tutorial: Using Alpha Images

ZBrush allows you to use alpha images to sculpt detail into the mesh. If none of the pre-loaded alphas work for the detail you would like, then you will need to create one. I prefer to make alphas in Photoshop.

1. Open Photoshop and create a new document.

FIGURE 8-12   Alpha creation.

2. Set the background to black and the foreground to white or gray.

3. Paint out the desired alpha shape.

4. Click Image>Mode>Grayscale to remove the color information.

FIGURE 8-13   Set to grayscale.

5. Save the document as a psd file.

I like creating alphas in Photoshop because it’s very easy to create much more complex images. In the images below, instead of starting with a black background, I started with a close-up photograph of some skin.

FIGURE 8-14   Various alpha images.

FIGURE 8-15   Various alpha images.

Tutorial: Creating Wrinkles and Skin Pores

Now it’s time to detail the characters in ZBrush. This is where the program really shines. The amount of detail you can add to a model is amazing.

Traditionally, wrinkles and skin pores would have to be created as a texture/bump map combination. With ZBrush, however, it’s incredibly easy to add crow’s feet, laugh lines, etc.

1. Load your character into a new session of ZBrush.

2. Make sure your character has been divided into at least a million polygons. You will need the extra detail in order for the alpha to deform correctly.

3. Click Alpha>Import and load the wrinkle alpha you created.

FIGURE 8-16   Loading the alpha in ZBrush.

4. Under the Stroke menu change the brush stroke to DragRect. This will make it much easier to place wrinkle alpha.

5. Check either Zadd or Zsub to add or subtract the alpha.

6. Adjust the Z Intensity to the desired amount.

7. Drag on the mesh where you want to add wrinkles.

FIGURE 8-17   Rectangle brush stroke.

FIGURE 8-18   Adding wrinkle.

8. Continue until you like the amount of detail. Keep in mind that you can adjust the Z Intensity every time you make a stroke. That way you can have some wrinkles deeper than others.

9. When sculpting with alphas they tend to be a bit flat. Turn off the alpha and use a low-intensity Inflate brush to puff out the skin between the wrinkles.

FIGURE 8-19   Puff out the alpha.

10. Click Alpha>Import and select the alpha skin pore file you created. This will load it as the current alpha image.

11. Under the Stroke menu change the brush stroke to DragRect. This will make it much easier to place the skin pore alpha as you work.

12. Click the Zsub button to subtract the alpha.

FIGURE 8-20   Skin pore alpha.

13. Adjust the Z Intensity to the desired amount.

14. Drag on the mesh where you want to add the pores.

15. As with wrinkles, the pores can appear somewhat flat. Turn off the alpha, puff out the pores by using a low-level Inflate brush.

16. Use different sized dots for the different sections of the face.

FIGURE 8-21   Final skin pores.

Tutorial: The Extract Tool

The new extract function is a great feature of ZBrush. Extract allows you to copy and separate selected areas of the mesh. This is a great way to add clothes or other props.

1. Load your character in ZBrush and place the tool onto the canvas.

2. Press Ctrl and LMB click to paint a mask of the areas you would like to extract.

FIGURE 8-22   Painting a mask to extract.

3. If desired, select alpha and remove parts of the mask. This will create holes in the extraction. The drag rectangle works great for this.

FIGURE 8-23   Using an alpha to create complex shapes.

4. In Tool>Subtool set a thickness for the new extract.

5. Click Tool>Subtool>Extract. The extracted mesh will be added as a new subtool. If the extracted subtool isn’t of the correct thickness, delete it by pressing Tool>Subtool>Delete. Then adjust the thickness and press Extract again. Make sure you have the correct subtool selected before pressing delete.

FIGURE 8-24   The extracted subtool.

Tutorial: Sculpting Hair and Cloth

Hair and folds in cloth are also very easy to create in ZBrush. Using a few brush strokes you can quickly get very nice results.

1. Load your model into ZBrush.

2. Make sure it is at least a million polygons.

3. Change the brush to Clay.

4. Adjust the Z Intensity to a higher number.

5. Click on Stroke>Lazy Mouse. This amazing tool gives a drag effect whenever you paint. It really helps in creating hair and folds.

6. Drag along the hair or fold line.

FIGURE 8-25   Lazy Mouse.

7. Now press the Alt key while dragging along and over the hair or fold. This will switch the brush to Zsub. Because you are using a clay brush, it will create blends and folds whenever the Zadd and Zsub strokes move over each other.

8. Continue using the above steps until the hair is complete.

FIGURE 8-26   Hair.

Tutorial: Using ZProject for Texturing

After all of the detail has been added, it’s time to create the textures. Texturing in ZBrush has been greatly improved with version 3. Using the ZProject brush, a texture can quickly be applied from a background image onto the desired mesh. Polypaint is another way to texture in ZBrush and will be covered in Chapter 9. ZProject is discussed here because it’s done using brushes.

1. First you need to create an image that has views of your character from multiple angles.

FIGURE 8-27   Reference image.

2. Create a new scene in ZBrush.

3. Set the Document width and height to match your image.

4. Import the image file.

5. Place your mesh on the canvas. Remember to press "t" to enter edit mode.

6. Scale and position it next to the front snapshot.

7. Change the material to a white Fast Shader.

8. Click Color>Fill Object.

FIGURE 8-28   Position the mesh.

9. Change the brush to ZProject.

10. Turn off Zadd.

11. Turn on RGB.

12. Press "w" to enter Transpose mode. Transpose mode is a new editing mode that allows you to move, rotate, scale, or texture sections of a model.

13. Click on the forehead of the mesh and drag over to the forehead of the image. Release the mouse. You will see the Transpose circles appear.

FIGURE 8-29   The Transpose Tool.

14. Press "q"to enter Draw mode.

15. Paint the forehead area.

FIGURE 8-30   ZProject painting.

FIGURE 8-31   ZProject strokes.

16. Keep using the above steps to paint the mesh. When you are done painting the front view, position the mesh next to the side view and repeat.

Tutorial: Posing the Character

We looked at some tools that help you work with a model after it has been posed. Thankfully ZBrush has created some easy-to-use posing tools. Keep in mind that because of layers and poseable symmetry, you can pose your model at any time and continue to sculpt symmetrically.

1. Press Ctrl+LMB and drag over the parts of the model you don’t want to transpose. The masked areas will remain locked in place.

FIGURE 8-32   Masking part of the body.

2. Press Ctrl+LMB click again on the mesh if you want to smooth out the edge of the mask.

FIGURE 8-33   Smooth the mask transition.

3. Press Rotate to enter the Transpose Tool.

4. Drag from the starting point to the end point to redefine the Transpose Tool.

FIGURE 8-34   The Transpose Tool.

5. Click and drag the end circle to rotate the arm down.

FIGURE 8-35   Posing the model.

6. Continue masking parts of the model and posing the mesh.

FIGURE 8-36   Final posed model.