How Are Computer Generated Graphics Created? (Continued)
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Step 2: Adding Color - Texture Mapping
Now it's time to add some color. At this point we also define the properties of the material (the basic color, glossiness,
transparency amount, and other parameters). We simply create different materials and tell the software to assign each
material to the proper object that we've modeling up to this point.
This looks a lot better than the wireframe images we've done, but it still needs something else to give it a more realistic
look. For that we can use texture mapping. In a nutshell, texture mapping is equivalent to wrapping Christmas presents in
colorful patterned paper. In the computer graphics world, the gift box is the model, and the wrapping paper is a digital
image. The image could be a photograph taken with a digital camera, or a digital image created in a paint package like
Let's add some age to the teapot by giving it a texture map using the image shown in Figure 4.
Screen shot of a
model with a
Texture Map JPEG
Figure 5 shows how the teapot model looks with the texture map applied. Notice that the texture replaced the base color of
the teapot, but the original shininess parameters still apply. Also, the image is wrapped around all surfaces of the teapot.
Texture creation and mapping is an art unto itself, and getting the right "look" is often a very time consuming process.
Illustrations don't typically use much in the way of texturing, as realism is not the goal. While this does cut considerable time
out of the texturing process, it doesn't eliminate it completely.