Game Development Reference
In-Depth Information
needed), the more effectively this particular step of the scenography creation
process (i.e., modeling, UV layout, texturing) is completed, the more efficient
the process will be.
UVs
The process of creating and editing UVs can be one of the most frustrating in all
of 3D. There is little intuitive about them. Unfortunately, understanding UVs and
how to manipulate and utilize UV space is one of the most important aspects to
visually believable projects—and absolutely critical to effective games.
So what are UVs? Well, they really aren't so much of a
what
as a
where
. UVs are
coordinates. They are involved in the complex problem of how to take a 2D
texture and wrap it around a 3D form. Think of the problem as much like that
of cartographers attempting to create a map of the earth. How do you take a
sphere and flatten it out into a flat shape on a page?
UV mapping
is the process of taking three-dimensional shapes, and
unfolding
or
unwrapping
them into a two-dimensional representation where a texture
can be painted on them (
Figure 3.1
). UV coordinates on a surface are the
locations at which to “pin” the textures. Once these locations are pinned down,
even if the surface flexes or distorts, the texture will flex and distort with it.
At the end of the day, UV mapping is what helps a texture look “right” on a
surface. A poorly laid out UV map yields unsightly stretching and pinching of
the texture that is applied to it. A well-executed UV map produces believable
surfaces with textures that belie the usually simple geometry beneath it. In
games especially, where textures do much of the visual work, a good UV map
is critical to visual success.
In the following tutorial, we will be looking at three ways to create UV maps.
Through this process, it will be important that we understand texture space
and how it relates to 3D space. We will look at the UV Texture Editor within
Maya and how it allows for the manipulation of UVs. We will look at Maya's
automatic mapping options, its unfolding capabilities, and manual mapping
and manipulation of UVs.
Figure 3.1
An illustration of UV
unwrapping.
