The multi-opacity masking feature is very useful to visualize the results of an automated segmentation process. However, it is often desirable to let the user perform such segmentation manually.

Sculpting provides you with this ability in a flexible and easy to use way. It allows you to rotate the volume to the desired orientation and then use a freehand drawing tool to outline part of the volume. This effectively splits the volume into the part inside of the outline and the part outside of the outline. You can then decide which of these parts should be displayed and which should be hidden. If you wish, you can then rotate the volume and define an outline from another direction.