"Many times, objects contain numerous attributes that
define how they look, and they're not always perfectly uniform in
relation to the object. For example, a used paint can would have
paint dripping down the sides of the can—if we were creating
this can in 3D, we'd have to tell Blender that there is a specific
spot on our 3D mesh that contains different attributes than the
rest of the mesh. This is where UV mapping comes in handy. UV
coordinates are, in simple terms, a two-dimensional representation
of the texture coordinates of a three-dimensional object. They
allow us to tell Blender specific properties about specific areas
of our objects in a scene.
"In this article by Aaron W. Powell, author of Blender 2.5
Lighting and Rendering, we're going to talk about creating custom
textures for our scene and how to bring them into Blender. We will
learn how to create a custom UV map and texture for an object in
our interior scene."