Surfacing - Blender Foundations: The Essential Guide to Learning Blender 2.6 - page 214

Figure 7.52 Painting the lower texture directly in the 3D view.
Combining Painted Textures with Procedurals
Painted texture maps can be combined with other textures in creative ways to lessen your work load. For
example, the walls in our scene use procedural texturing with generated coordinates. There is no reason
that you cannot also unwrap the walls of the room, create a second texture channel, and use the paint
tools to add dirt and scuffing to the walls. To do something like this, you begin with a completely white
image instead of black, then paint dirt into places it would normally occur: around window sills where
people rest their hands, near baseboards, in corners. Then, apply that image map to the existing color
scheme using Multiply mode and UV coordinates. Anything that is white in the image will leave the
underlying colors unaffected, while any dirt that you paint will darken it.
Live Mattes: Camera Projection
In film and television production, backgrounds are often generated or enhanced through the use of matte
images. Mattes are photographs, illustrations, or paintings that are used as backgrounds for live action. Great
mattes are indistinguishable from the real thing, although they restrict camera movement. If you have a
simple 2D image as your background and you move your camera, it will be obvious that things aren't
what they seem when the elements in the image fail to move in a realistic fashion. When working in 3D,
there is a simple way to map a matte onto corresponding 3D objects so that limited camera motion pro-
duces the correct effect. This technique is called camera mapping .