Emissive clipping planes for volume rendering

Figure 1. The inner walls of the colon are easy to see. On the right the colon extends into the volume. While the walls are clear, the clip plane itself makes the image too distracting to be useful. Figure 2. The emissive clip plane reveals muscle (blue), fatty tissue (dull red), the hip bone in the lower left and a fibrous mass in the lower right. The resulting image shows both the clip plane and the colon walls.