deep texturing

Figure 1. Figure 2. Figure 3. Click for a closer look. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8.

Sometimes animators can get too wrapped up in geometry when trying to make realistic environments. This month we will show you how to combine the best of modeling and texturing.

introduction
Many animators know how you can save a lot of heartache by creating a large model in pieces and then duplicating those pieces when creating a large environment. This trick works great if you are building hallways, warehouses, or other symmetrical structures. But what if the symmetrical structure you are building are complicated as well? Those polygons can add up quick. If you use a 3D program that can use an alpha channel to map a texture onto geometry then you to can build complicated environments with the fewest of polygons.

why not polygons
Hollywood still uses a lot of matte paintings. When time is not on your side a good digital matte painter can usually work faster than an animator when it comes time to create a realistic environment. But by using some of a matte, and texture painter's tricks you can create great environments that are 3D and hold up to most kinds of animation. The advantage of this is you can create a realistic environment in less time will render faster and be easier to work with.

our problem
In a recent project that we were working on we were tasked with creating a circular labyrinth that a camera had to zoom in and out of. The surface attributes of said labyrinth were supposed to have a look we termed techno-gothic. Think of the Borg cube in Star Trek: First Contact. Our dilemma was that to create the kind of detail we wanted would have entailed creating a maze with a couple of million polygons and dozens of internal lights. We found a better way.

our solution
We jumped into our modeling program, Form-Z, and created a series of mechanical looking panels with all sorts of odd shapes on them. We created two mechanical panels and a floor grid to use in our maze. (see fig. 1) We then took these elements into our animation program, Electric Image, and applied a procedural erosion map, a metal reflection map, and a variety of lights to get our techno-gothic look. We then took these rendered elements into PhotoShop to create our texture maps. By using a custom set of grime brushes in PhotoShop we were able to quickly scum up our rgb maps and create nice bump and specular maps. When we were done we had four textures to work with. Our first texture was the back of the mechanical wall, this was heavily lit and would be applied as a luminance map to geometry so the lighter parts would appear to give off a sublet light. (see fig. 2) Our next texture was our outer mechanical wall. By applying a clipping or alpha matte to this texture along with our specular and bump maps this layer would appear to be a mechanical grid work sticking out from the rest of the wall. (see fig. 3) Our final wall texture was more detail that we were going to sandwich between the other layers. In addition, we had a grid texture for the floor.

the process
Now before we went and built our maze to take maximum advantage of the texture we did some tests to see how the textures would play with each other. In Form-Z we created a simple wall and floor section that we brought into Electric Image and then lit with a shadow casting parallel light. To show you what all this shapes look light we rendered out an image of the shapes slightly offset. (see fig. 4) We then applied the floor grid texture with a clipping map. As you can see the clipping map removes all geometry that doesn't fall in the values of the alpha channel. (see fig. 5) Since we are using flat mapping with negative z space enabled the map repeats on the other side of the geometry. In this case is gives us a nice effect of more depth so we are going to keep it. If we turned if off the texture would appear to be mapped to a flat plane. We then applied the texture for the outer wall. Notice how Electric Image actually treats the clipping map as geometry and casts a shadow of the texture's shape on itself and the yellow plane. (see fig. 6) Next we applied the middle wall layer with a clipping map and then we applied the base wall texture with a slight luminance so it would read behind the other textures. Finally, we removed the offset from the textures and aligned the middle texture so was sandwiched between the front and the back of the outer texture (see fig. 7)

the result
We then duplicated our wall and floor and rendered out some test shots to see how the resolution held up. We were pretty pleased with these images considering the environment only consisted of a few hundred polygons and a took a little less than a minute and a half per frame to render. We also knew that our camera would be moving very fast and that motion blur would help hide that our maps looked a little soft at extreme angles. Finally, we turned off one of the back panels and cast a light through our texture giving us an exciting volumetric light effect. (see fig. 8) To see a QuickTime sample of this project click here. Happy texture painting and take care.

Copyright © 1998, Chris Bernard


Chris Bernard lives in Chicago and works as an animation and design director at an integrated marketing communications company. He can be reached at cb@avidgroup.com.

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