In scientific visualization and computer graphics, volume rendering is a set of techniques used to display a 2D projection of a 3D discretely sampled data set, typically a 3D scalar field.A typical 3D data set is a group of 2D slice images acquired by aCT, MRI, or MicroCT scanner.Usually these are acquired in a regular pattern (e.g., one slice every millimeter) andusually have a regular number of image pixels in a regular pattern.