VOLUME VISUALIZATION TARGETS THE PROBLEM of extracting and dis-playing the important and relevant parts of a volumetric data set. This goal can be separated into two subgoals: first, emphasizing important regions, for example, by using bright colors and high opacities; second, deemphasizing or hiding unimportant regions. Volume clipping specifically addresses the second subgoal by completely cutting away unimportant areas. It can be regarded as the 3D analogue of image cropping or extraction, known from image processing and editing.