Interactive volume rendering

Volume rendering is the display of data sampled in three dimensions. Traditionally, visualization of such data has been through conventional computer graphics line or surface drawing methods preceded by processes that coerce the sampled data into a form suitable for display. This approach is being replaced by new techniques which operate directly on the three dimensional samples to avoid the artifacts introduced by the use of conventional graphics primitives. Volume rendering is a compute-intensive operation. This paper discusses an approach for volume rendering in which interactive speed is achieved through a parallelizable forward mapping algorithm, successive refinement, table driven mappings for shading and filtering, and the avoidance of complex machine classification of the data. Since the renderer is interactive, users are able to specify application specific mapping functions on-thefly. Current applications include molecular modeling, geology, computed tomography, and astronomy.