ZAppLink

ZAppLink is a free plug-in for ZBrush available from Pixologic. ZApplink allows you to seamlessly integrate ZBrush’s painting tools with Photoshop. This program will allow you to use all your favorite Photoshop brushes and filters in conjunction with ZBrush. ZAppLink must be downloaded and installed. Download ZAppLink from the Download Center at . In the section called ZAppLink Properties (Figure 5-45), click the ZAppLink Properties to open this menu; then click the name to unroll the menu and access the options.

Figure 5-45: Accessing the ZAppLink menu under Document

The ZAppLink Properties window contains the options for storing views of your model. Views allow you to store a model’s position on canvas so you can use layers in Photoshop. We’ll cover views later in this section. For now let’s look at ZAppLink as a connection to Photoshop. Load the character model from the previous section. Draw the Stingerhead on the canvas and enter Edit mode. Orient so the horns are visible from the top, as shown in Figure 5-46. Mask the horn area and invert so the horns are now unmasked. Load ZAppLink by clicking the ZAppLink button under the Document menu. Photoshop will now open (or the program you have on your system that opens PSD files).

Figure 5-46: Unmasked horns seen from top-view orientation before opening ZAppLink

1. Since we only want to color the horn, mask out the rest of the head. The simplest way to do this is to mask the horns and then invert. Orient the head on the canvas so the top view of a horn fills the screen. Once the head is placed, you will load ZAppLink by pressing Ctrl+Shift+S or by opening the document window and clicking the ZAppLink button. This will load the ZAppLink window (Figure 5-47).

Figure 5-47: The ZAppLink window

2. Click the Drop Now button and Photoshop will load with the ZBrush document as an open image (Figure 5-48).

Figure 5-48: Canvas in Photoshop

The ZAppLink document contains three layers (Figure 5-48):

• The top represents the shading from ZBrush and should not be altered. You can turn this one and off to see the color information with no shading information.
• The second layer is the ZBrush document window image with a layer mask. This layer mask simply cuts off any overpaint that is not directly on the model.
• The third layer is simply a background. When editing, you can change layer 2 or add new layers, but you must collapse your changes into layer 2, always preserving the layer mask when asked. You must have the original three layers before returning to ZBrush (see Figure 5-49).

Figure 5-49: Anatomy of a ZAppLink document layer system

3. Open an image of a horn in Photoshop, and then copy and paste it over the ZAppLink image of the document window. Erase the edges of the image so it blends off (Figure 5-50).

Figure 5-50: Erase edges of the photo to create a softer blend.

4. When you have completed editing in Photoshop, collapse your new layers down to layer 2. Before collapsing to layer 2, Photoshop will ask if you want to preserve the layer mask; select Preserve. Be sure not to click Apply. Now save your document and return to ZBrush.

5. You will see a ZAppLink prompt asking if you want to reenter ZBrush or return to the external editor. Select Re-enter ZBrush and, on the following menu, choose Pickup Now. The photo reference that was placed in Photoshop will now bake into the polypaint of the model. You can rotate to the other horn and repeat the process. ZAppLink is not limited to simply projecting photo references. You may also use the entire suite of Photoshop painting tools.

6. By continuing to rotate around the head, dropping and projecting a reference in ZAppLink, you can build up a base texture. Continue to adjust the color of the horns in PolyPaint and sample colors directly from the canvas using the projected photo reference as a guide.

For more examples of using ZAppLink, please see the video files on the DVD.

Let’s make some final tweaks to take the paint job one step further. Try using cavity masking (Tool ⇒ Masking ⇒ Mask By Cavity) and paint a cool brown with a very light intensity into the recesses and skin details. On this character, I selected a purple hue and added some tiny veins around the nostrils, eyelids, and horns (Figure 5-51).

Figure 5-51: A selection of details that help push the realism of the head include spider veins around the nose and eyes.

That completes painting the creature skin. By combining Projection Master, ZAppLink, and polypainting techniques, you have painted a detailed character from scratch (Figure 5-52). In the next section we’ll discuss how to bake this polypainted texture into a UV map so this character can be rendered outside ZBrush.

Figure 5-52: The final painted Stingerhead character in ZBrush

Baking Polypaint to UV Texture Space

Once you have completed your polypaint, you will at some point want to bake it into a UV map if you plan on rendering outside of ZBrush (Figure 5-53). This simple process is outlined in the following steps:

Figure 5-53: The Stingerhead exported and rendered in Maya

You have now seen how to bake polypaint data into a single texture map. It is possible to use multiple UV regions to create several maps from a single polypainted model. If your UV set is broken across multiple UV regions you will need to extract the color maps using the Multi Map Exporter plugin covered in Chapter 9, “Normal Maps, Displacement Maps, Maya, and Decimation Master.”

This process also allows you to transfer textures from one UV set to another by converting a UV texture map to PolyPaint. To accomplish this, load a ZTool with a texture map, and convert the texture map to PolyPaint by clicking Tool ⇒ PolyPaint ⇒ PolyPaint From Texture while at the highest SubD level. Step down to level 1 and alter your UVs. Set your texture resolution under the UV Map menu and step back to the highest SubD level. Click Tool ⇒ Texture Map ⇒ New From PolyPaint to bake the color information into the new UV space.

ZAppLink Views

ZAppLink allows you to store a ZTool’s position on the canvas for later recall. To do this, you must store views under the Document ⇒ ZAppLink Properties menu. To store a view, position the model facing the canvas in the center of the screen. Open the main document window and click the ZAppLink Properties menu to open it. Click the Front button to store this view. Rotate to the side and click the Right button to store the right-side view. Notice that ZBrush will automatically store the opposite view for you; in the top view, for instance, the bottom view is automatically stored. If you need to clear a view, click the Clear button. If you need to save the views file for later use, click Save Views.

Now when you open ZAppLink, all the views will export as a single document (Figure 5-54). To work on a single view at a time, Alt-click the layer you want to work on to hide all other layers. Then turn on the visibility for the shading layer directly above it. When done, save your image and return to ZBrush. When you return to ZBrush, any changes made to any of the layers will update on the corresponding side of the ZTool. Click Accept for each view to keep the texturing information; otherwise, click Cancel.

Figure 5-54: ZAppLink layers in Photoshop

You can also use ZAppLink views to create a character sheet for your model. A character sheet shows the model in full rotation using the views you stored. To do this, once you have stored your preferred views click Document ⇒ ZAppLink Properties ⇒ Make Character Sheet. This will export each view to Photoshop and then combine them into a single character rotation sheet. This is very helpful when submitting work for critique or approval.

SpotLight for Texture Painting

ZBrush 4 introduced a new method of importing and manipulating texture reference images in ZBrush. This new toolset is called SpotLight. SpotLight is a suite of tools intended to streamline the process of managing multiple texture source images, manipulating the images themselves and then applying them to your models. SpotLight can also be used in conjunction with the TimeLine to create reference image planes in ZBrush.

The texture reference images in this section are from the photo reference website 3d.sk. 3d.sk maintains a huge library of human, animal, costume, and prop photo reference sets. All images are shot in extremely high resolution and from multiple angles. I have had a subscription to the site for many years now and I cannot recommend it highly enough. High resolution photos are indispensible when texturing your models and your sculptures will always be better when using photo reference. 3d.sk has been kind to offer several sets of free reference images, which are included on the DVD. Remember to subscribe to the website—the photosets are updated often so there is always new material to download.

SpotLight is accessed via the main Texture menu. To enable SpotLight, simply select a texture from the main Texture menu and click Add To SpotLight (Figure 5-55). This will cause the SpotLight interface as well as the selected texture to appear in the document window.

Figure 5-55: SpotLight activated

You can continue to add more images to the SpotLight by selecting them in the Texture menu and clicking the Add To SpotLight button. Figure 5-56 shows several imported images added to spotlight for use as texture sources.

Figure 5-56: Several textures loaded into SpotLight as reference

SpotLight has its own navigation controls. To move the SpotLight itself, click in the center of the orange circle. This will place the SpotLight as well as set the source for operations like Scale and Rotate. These functions will occur around the center of the orange circle at the center of the SpotLight (Figure 5-57).

Figure 5-57: The parts of the SpotLight

To move a texture, click on the texture itself to activate it. The texture will take on a red rectangle. Now click and drag anywhere on the texture to move it.

SpotLight consists of a ring of buttons. Each button represents a function that can be applied to the selected image (Figure 5-57). Click a button and its function name will appear in the center of the ring. You will use these functions to alter the shape or appearance of the texture reference swatch before using it to apply color to the model. Table 5-5 shows the function of each button.

Table 5-5: Parts of the SpotLight

Now that we have an overview of how SpotLight works, let’s use it to paint a model. Follow these steps to add some color texture using SpotLight:

1. Load the DemoHead ZTool. Draw the tool on the canvas and enter Edit mode. Change to the Basic Material. Center the head on the screen and add a few subdivision levels to support the polypaint detail you are about to apply.

2. From DVD folder sourceImages_forSpotLightload, load one of the reference photos. Click the Add To SpotLight button. Select the photo again, then load the remaining photos into SpotLight. With the first photo selected, the whole series will load into the SpotLight tool. Click the Tile Unified button to tile the images together on the side of the screen.

3. Select the front view image and place it over the head. I use the corner of the eye as a guide to line up and scale the image until it is close to the correct size. Place the orange circle over the corner of the eye and line the photo up to the model. Scale from this point (Figure 5-58). Remember you can use the opacity slider to make it easier to see the model through the texture image.

Figure 5-58: Scale the front view image to line up to the head. The image on the left shows the texture with opacity dialed back so you can see the underlying model more clearly.

4. Turn Opacity down so the image is barely visible. Dial up the Fade control so the SpotLight will feather when you enter Projection mode. With the opacity down you can see the effect this will have. This control will project a “spotlight” of texture with your brush as you paint. This is how SpotLight got its name (Figure 5-59).

Figure 5-59: Setting the SpotLight Fade control. Opacity has been turned down on the image before adjusting the Fade control.

5. You are now ready to enter Projection mode. Press the Z hotkey and you will see your brush now projects a circle of texture based on the image you just placed (Figure 5-60). Select the Standard brush and make sure that only RGB is activated on the brush—ZAdd and M should be off. Select the DragRect stroke. Click and drag from the center of the head and you will see the texture reference apply as polypaint data.

Figure 5-60: In Projection mode, the texture projects in the brush like a spotlight.

6. This applies an overall texture to the face. We will now zoom in for more detail. Center the eye on screen and press Z to exit SpotLight. Using the same techniques as before, scale the eye texture source to line up with the eye of the model. Press Z to enter Projection mode. Change the stroke to Freehand and brush around the eye area. Repeat this process for the mouth.

This is the basic process for using SpotLight as a texture tool. Please see the DVD for a video on SpotLight in use. You can also use SpotLight as a reference image plane tool. Follow these steps to create front and side reference planes:

1. Initialize ZBrush by pressing Preferences ⇒ Initialize ZBrush. This will clear the palettes of any custom tools and give us a clean slate to work with.

2. From the Lightbox ⇒ Tool menu, select the superAverageMan ZTool.

3. From the Texture menu, import headfront.jpg and headside.jpg from the DVD. Add these files to SpotLight.

4. Move the reference images and scale them to look like Figure 5-61. You want them to be sitting side by side in the window. To move both images, click in the open canvas to scale both images together and press Shift while you move them.

Figure 5-61: Scale and place the reference images as shown here.

5. You will want to adjust the opacity on the images so the model can be seen through them. Dial Opacity back just so the image is still visible but the model is discernable behind the texture. Remember if you hold Shift while adjusting the opacity, it will change for all images in the SpotLight.

6. On the Brush ⇒ Samples menu, turn off Spotlight Projection. This will cause the entire reference image to be visible when you press the Z hotkey instead of projecting the image through the brush (Figure 5-62).

Figure 5-62: Turn off Spotlight Projection under the Brush ⇒ Samples menu.

7. Press Z to enter Projection mode. Because we have not enabled SpotLight Projection, the reference images remain as overlays on the canvas. You can see and sculpt the mesh through the reference image. Move the model to line up with the side view of the head (Figure 5-63).

Figure 5-63: Line up the model with the side view image.

8. For the reference image plane to be useful, we need some way to restore the model to a set orientation relative to the front and side views. To store this position, we will place a keyframe on the TimeLine. For more information on the TimeLine, see Chapter 8, “ZBrush Movies and Photoshop Composites.” For now we will just use it to store our model positions. Click Movie ⇒ TimeLine ⇒ Show to enable the TimeLine. Click a dot on the TimeLine to store the current model position.

9. Move the model to line up to the front view image. Click further down the TimeLine to store another keyframe. You can now easily keep the head registered to either view. Simply press the left or right arrow keys to switch from the front and side orientations (Figure 5-64).

Figure 5-64: The Front view keyframe set

If you want to use this image plane setup for future sessions, you need to save the TimeLine and the SpotLight. The TimeLine will save with the ZBrush project file. SpotLights, however, save separately because they save all your texture images. Make sure you turn off WSize under the Document menu before saving the project. Otherwise this will cause your reference place to be out of alignment later.

You can save SpotLights for later use by clicking File ⇒ SpotLight ⇒ Save SpotLight or using the Texture ⇒ Save SpotLight button. SpotLights will save all your loaded textures at the maximum resolution. This allows you to keep all your favorite texture sources in one easy-to-access file. For example, you can create and save SpotLights for human skin, fur, reptiles, or rocks and have each ready when the project demands it.

Polypaint with HD

Using polypaint with HD allows you to completely overcome the texture resolution limitations in previous versions of ZBrush. With billions of HD polygons available for polypaint, you’ll find extremely high-resolution texture maps simple to create in ZBrush. If you have HD subdivision levels on your ZTool, ZBrush will include any color or sculpting detail found on the HD levels in the extracted maps.

The process used to paint into HD subdivision levels is the same as that described in Chapter 4 for sculpting details in HD levels. HD color and geometry can be rendered directly inside ZBrush or exported into high-resolution maps for rendering in other software. To texture paint into HD, follow these steps:

1. Load the superAverageMan ZTool from the Lightbox and enter Edit mode.

2. Step up to the highest subdivision level. To add HD subdivisions, select Tool ⇒ HD Geometry and click the Divide HD button. At the top of the screen you will see a notice telling you how many polygons are available. While you can divide into the billions, try to remember that the higher you divide here, the smaller your working area will be.

3. Hold your mouse over the area you want to paint and press the A key. ZBrush will isolate a radial region consisting of the maximum number of HD polygons the system can display. This number is set by ZBrush on install to an ideal value based on your system resources.

4. You can now start polypainting into the active area. You can use SpotLight or ZAppLink for this process. Figure 5-65 shows polypainting into HD geometry. The jagged line on the upper arm is the border of the active HD region. Notice the difference in the color texture resolution when HD is off (Figure 5-66).

Figure 5-65: Polypainting into the active HD region

Figure 5-66: Compare the resolution between polypaint and polypaint in HD. The fine texture of freckles and pores is more apparent on the left side of the image where HD is used.

When you are done painting the active HD region, hover the mouse over the background and press A. This will exit HD mode. You will see your colors become soft again—the color resolution is still there but only visible when rendering in HD. You can now hover your mouse over another area and press A to enter HD mode. As we saw in Chapter 4, you will need to work your way around the whole model in overlapping HD regions building up the color texture.

Extracting Maps from the HD

There are two methods of extracting the HD color information into a texture map that can be exported to other software. Both approaches require that the mesh have UV coordinates assigned.

To extract the polypaint to a single texture map, follow these steps:

1. Make sure you have UVs assigned to the mesh at the lowest subdivision level. Step to the highest standard subdivision level and make sure the HD Subdivision Level slider is all the way up (Figure 5-67).

Figure 5-67: Set the standard and HD subdivisions to the top level.

2. Press Tool ⇒ Texture Map ⇒ New From Polypaint. This will create a UV color map with the HD color resolution. This will create a single map based on the UV coordinates within 0 to 1 on your model. This method is the simplest and the one most often used.

If you have multiple UV regions and you want a color map for each one, you will need to use another approach. The benefit of multiple UV regions is discussed and demonstrated in Chapter 9. Suffice it to say it offers extremely high quality by breaking your color maps up into multiple high-resolution maps for a single figure. See the DVD for a video on this process.

UV Master Plug-in

UV Master is a new plug-in for ZBrush that helps users create and lay out UVs that are fast, efficient, and human readable all from within ZBrush and often with just a single button click. The plug-in is available from www.pixologic.com. Install the plug-in by placing the ZSC file and data folder in the PixologicBrush4StartupPlugs folder. Place the UVMaster_checkers folder in PixologicBrush4Textures so it is accessible in Lightbox. Restart ZBrush and the UV Master plug-in will be found under the ZPlugin menu.

1. To create UVs for a model, simply load the ZTool for which you want to generate UV coordinates (Figure 5-68).

Figure 5-68: Load the ZTool you want to create UVs for. The UV Master plug-in menu is open on the right side of the screen.

2. Click the Work On Clone button to create a clone of the current ZTool with no subdivision levels. Click the Unwrap button and ZBrush will generate UV coordinates.

3. From Lightbox select one of the checker textures. Load this into the texture swatch under Tool ⇒ Texture Map. This checker map will help you see the result of the UV layout (Figure 5-69).

Figure 5-69: Use the checker textures to visualize the UV layout.

4. Click the Copy UV button to copy the UV layout into memory. Select the original ZTool. Step down to the lowest subdivision level and click the Paste UV button to transfer the UVs to the original mesh.

It is important to understand that UV Master is intended to be an automatic mapping solution for artists. The seams may be placed in unexpected areas like the center of the face or the middle of the front of the body. ZBrush is calculating the most efficient placement; it is also using the Ambient Occlusion methodology to try to place seams in shadow areas. While the UVs generated may be a good start for production work, they are usually more than enough for an artist trying to generate a single render or character rotation. For more information on manually editing UVs, check out my second book, ZBrush Digital Sculpting Human Anatomy. In Chapter 5, “Texture Painting,” Eric Keller gives an in-depth look at the Headus UV for laying out UV coordinates.

Control Painting Tools

You can exert some control over the placement of seams and the density of the UV resolution by using the control painting tools available in UV Master. Control painting has four modes. Protect mode will protect some areas from UV seams, such as the front of the body or face; Attract mode will help guide ZBrush to place edges in areas such as the back of the head or legs; Density allows you to paint areas where you want there to be more UV resolution, like the face; and Erase simply lets you erase and rework areas you have painted. In this exercise we will look at using control painting to adjust the UVs created for the werewolf ZTool.

1. Load the werewolf ZTool from the DVD. Step to the lowest SubD level and click the Work On Clone button under the UV Master menu.

2. Click the Check Seams button to see where the seams were placed by default (Figure 5-70). As you can see, the seam placement is not ideal. We will use control painting to correct this.

Figure 5-70: The automatic seam placement is not ideal on the werewolf.

3. Click the Enable Control Painting button under UV Master and click the Attract button. You can now paint in blue on the surface of the model. Paint a stroke down the back of the trunk arms and legs to help attract the UV seams to these areas (Figure 5-71).

Figure 5-71: Use control painting to attract the seams to the back of the figure.

4. Click the Unwrap button to recalculate the UV layout. Now you will see the seams have been placed in the areas indicated by the blue paint strokes (Figure 5-72).

Figure 5-72: The new seams are placed on the back of the figure.

5. From the Lightbox select one of the checker textures and apply it as a texture to the werewolf. This will help illustrate the density of texture space applied to each part of the model as well as the placement of the seams. In Figure 5-73 you can see that the density of UV space in the face could be higher.

Figure 5-73: The density of UV space is low for the face.

6. Select Density under Control Painting. Click the x3 button to specify the painted areas to get three times more texture space than the unpainted areas. When you have painted in the head and ears, click Unwrap. In Figure 5-74 you can see the modified face on the right. Notice how much denser the UV space is for the head. This will allow for more texture detail to come across in the map.

Figure 5-74: Increasing density with control painting. The head on the right has had the head texture density increased three times compared to the body.

7. When the UVs are completed, click Copy UV and then select the original ZTool and click Paste UV. This will transfer the UVs to the original werewolf ZTool.

Congratulations. You have now completed the exercise on UV Master. You will find that UV Master is an incredibly powerful plug-in that frees artists to take advantage of human-readable UV layout while harnessing the speed and power of an automated process.

Although this concludes this chapter on painting in ZBrush, there are many more topics and approaches to cover. I encourage you to check the video exercises on the DVD for more information on texturing in ZBrush.