cycles materials

This Blender 2.65 Cycles Tutorial illustrates How to create invisible Mesh Lights using Light Path Node, 'Is Camera Ray' as well the Ray visibility options in Object Properties. It also explains the pros and cons of each method

This Blender 2.65 Cycles Tutorial illustrates How to isolate objects on shadeless white background using cycles Material node setup for World. It also describes a node setup to cast reflection on objects while world appears white to the camera using Light Path Node.

This Blender 2.65 Tutorial will help in Understanding the concept of holdout shader. Holdout material, as the name suggests, holds out the surface from being exposed to the camera - and will dig in deep through other surfaces too - thereby creating holes in the image.