UV Unwrapping


UV unwrapping is a necessary function prior to skinning a model. Consider it part of the modeling process in the context of this book. However, in this chapter we'll deal with the texture processing part of skinning a model and use models I've provided on the CD. Later you'll create and skin your own models and do the unwrapping and other things. We'll cover how the unwrapping works in more detail then.

When we want to apply textures to 3D objects, we need a system that specifies where each part of a texture will appear on which parts of a model. The system is called U-V Coordinate Mapping. The U-coordinate and the V-coordinate are analogous to the X- and Y-coordinates of a 2D coordinate system, though they're obviously not exactly the same.

Imagine (or you can actually try this at home yourself) taking a closed cardboard box and slicing it open along the edges. Then lay the whole thing out flat on the kitchen table, with no parts overlapping parts. There, you've unwrapped your box. Now get out your crayons and draw some nifty pictures on it. Then glue it all back together again to make a box. I think you get the idea.

With UV unwrapping we apply the technique to some complex and irregular shapes, like monsters and ice cream cones.




3D Game Programming All in One
3D Game Programming All in One (Course Technology PTR Game Development Series)
ISBN: 159200136X
EAN: 2147483647
Year: 2006
Pages: 197

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