<em>Inspired 3D</em>: Organic Texture Mapping Tutorial — Part 2

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All images from Inspired 3D Modeling and Texture Mapping by Tom Capizzi, series edited by Kyle Clark and Michael Ford. Reprinted with permission. [1]

The following, a continuation of the tutorial on Organic Texture Mapping [2], which was published earlier this month, is next in a number of adaptations from the new Inspired series published by Premier Press. Comprised of four titles and edited by Kyle Clark and Michael Ford, these books are designed to provide animators and curious moviegoers with tips and tricks from Hollywood veterans. The following is excerpted from Modeling & Texture Mapping.

Import the Textures into Photoshop
Deep Paint can create high-quality 2D image maps by interpolating the 2D ortho-graphic texture images that were created earlier onto a 3D model. This would be very time consuming to do in a 2D paint program. But the 2D editing tools in Deep Paint are not as stable and reliable as the tools in Photoshop; therefore, Deep Paint has a plug-in that facilitates the import and export of 2D images to Photoshop.

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[Figure 33] The wing texture is imported from Deep Paint. [3]

The texture maps that were created in Deep Paint are imported back into Photoshop for final clean-up using the Deep Paint plug-in. This process is not only efficient and fast, but it also creates an image of the UVs that appears as a layer in Photoshop that helps in the process of painting textures in 2D.

Wing

1. Open the wing texture in Photoshop. The bottom of the wing will be missing. The barn owl’s wing has a light underside that matches the belly. Import the texture created for the side projection texture into Photoshop (Figure 33).

2. Cut and paste sections of the white spotted texture to the underside of the wing, making sure to keep it on a separate layer than the rest of the wing (Figure 34). Pay attention to the direction of the feathers; if necessary, rotate the feathers (Figure 35).

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[Figures 34 & 35] Texture from the side image is cloned on the wing texture (left). The rest of the wing underside is filled in (right). [4]

3. Clean up the white areas and merge with the gray-brown areas. Blend where the two colors meet (Figure 36).

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[Figures 36 & 37] The wing texture (left) is cleaned up. The foot UVs (right) before an additional toe is added. [5]

Toes

1. Export the color image layer only. Repeat the process for the other wing.

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[Figures 38 & 39] The toe map after the toe is added (left). The body texture is shown (right) being edited in Photoshop. [6]

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[Figure 40] The cleaned up body texture map. [7]

2. Next, texture map for the owl feet needs to be cleaned up. After importing the file from Deep Paint, just one toe needs to be filled in (Figure 37).

By using the clone tool, the toe can be easily painted by copying one of the other toes (Figure 38).

Body and Beak

1. Bring in the body file. A lot of stretching will occur through the middle of the belly of the owl and many blank areas will appear throughout the texture. To fill in the belly area, the same “side photo” (refer to Figure 29 [8]) created earlier will be used. Using the same cut and paste and clone methods used for the wings, the underside of the body can be filled in (Figure 39).

2. Zoom in close to the face and blend between the head area and the gray area. Clean up the areas around the eyes and then blend the gray top into to the white underside (Figure 40).

3. Save the body texture. Next edit the texture of the beak. Import the texture map for the beak from Deep Paint. The face projection should be mostly projected onto the top of the beak, leaving the underside blank. Use the clone tool in Photoshop to fill in the lower beak texture. With this model, a thinner, smaller beak is faked by manipulating the textures, so keep the sides of the beak looking like facial feathers (Figure 41).

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[Figures 41 & 42] The bottom of the beak is filled in, and the top beak is cleaned up (left). This is a test render of what the preliminary textures look like before clean up. [9]

Details and Clean-up
Small details can push the realism into the realm of photo-realism. These small items can make or break the final image.

1. Take the newly created texture maps and apply them to the color channel of the owl. The rendered image can be seen in Figure 42.

2. You will do final clean up after you have created the rest of the color maps.

3. Next, create the feather textures. Select one of the feathers of the model and export it out to Deep Paint. Create the striated pattern of the feather on the feather geometry. This is accomplished using a combination of photographic texture reference and hand painting. Once again, you have two different colors for the top and the bottom (Figure 43).

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[Figures 43 & 44] Feather color textures created in Deep Paint (left). Simple bump maps for feathers (right). [10]

4. The individual feathers will require bump, specular and transparency maps in addition to the color map created in the previous step. For the bump map, individual ridges on a feather should not be created, which would cause crawling or moiré in the finished rendered image. Simply draw a faint line for the stem of the feather (Figure 44).

5. For the specular map, it is only necessary to break up any specular hits and keep the values low. The Photoshop cloud render was used to create the specular map shown in Figure 45.

6. Because this model does not have the many layers of feathers that an owl has, a transparency map should be applied to the tips of the feathers. This will help give the illusion of depth and give a more realistic look to the owl in flight (Figure 46).

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[Figures 45 & 46] A cloud render used for a specular map (left). The transparency map for the tips of the feathers (right). [11]

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[Figure 47] This image shows the feather textures applied to the model. [12]

7. Now comes the big cheat. Remember the image of the checkerboard on the feathers and the UVs were not the same for all the feathers (Figures 3-5)? This will now allow these feathers to be mapped very quickly. Rather than having to make variations of a feather, just one image will be used to map all the feathers. The slightly different UVs give the impression of variation (Figure 47).

8. Next assign color to the eyes. Color the eyes a shade of black, but avoid using 100 percent true black. Nothing that shoots on film will ever be 100% black. Also, give the interior of the beak a nonintrusive dark color (Figure 48).

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[Figure 48] Eye color and beak interior color is applied. [13]

10. With such a colorful owl, the bump can be very simple. Also, because an owl’s wings are quite smooth, you will forego bumping them. Either in Photoshop or in Deep Paint, create a soft, billowy bump map for the body and legs (Figure 49).

11. For the specularity maps of the body, legs and wings, a simple noise map created in Photoshop will work perfectly well. (Figure 50).

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[Figures 49 & 50] A simple bump map is applied to the body texture (left). A simple specular map is applied to the model (right). [14]

12. Apply them all to the owl, and the textures are finished!

This process was used to create the textures on the owls in the film Harry Potter and the Sorcerer’s Stone. The owls as they appear in the film have additional feathers added using Rhythm & Hues’ proprietary software system, giving a heightened level of realism.

To learn more about constructing 3D characters and other topics of interest to animators, check out Inspired 3D Modeling and Texture Mapping by Tom Capizzi; series edited by Kyle Clark and Michael Ford: Premier Press, 2002 (272 pages with illustrations). ISBN 1-931841-50-0 ($59.99) Read [15] more about all four titles in the Inspired series and check back to VFXWorld frequently to read new excerpts.

Author Tom Capizzi (left), series editor Mike Ford (center) and series editor Kyle Clark (right).

Tom Capizzi is a technical director at Rhythm & Hues Studios. He has teaching experience at such respected schools as Center for Creative Studies in Detroit, Academy of Art in San Francisco and Art Center College of Design in Pasadena. He has been in film production in L.A. as a modeling and lighting technical director on many feature productions including Dr. Doolittle 2, The Flintstones: Viva Rock Vegas, Stuart Little, Mystery Men, Babe 2: Pig in the City and Mouse Hunt.

Series editor Kyle Clark is a lead animator at Microsoft's Digital Anvil Studios and co-founder of Animation Foundation. He majored in film, video and computer animation at USC and has since worked on a number of feature, commercial and game projects. He has also taught at various schools, including San Francisco Academy of Art College, San Francisco State University, UCLA School of Design and Texas A&M University.

Michael Ford, series editor, is a senior technical animator at Sony Pictures Imageworks and co-founder of Animation Foundation. A graduate of UCLA’s School of Design, he has since worked on numerous feature and commercial projects at ILM, Centropolis FX and Digital Magic. He has lectured at the UCLA School of Design, USC, DeAnza College and San Francisco Academy of Art College.