VOLUME GRAPHICS

Hardware and memory advances in the seventies enabled the evolution from vector graphics to raster graphics. Now, research in volume visualization is offering an alternative to traditional surface graphics. Volume graphics, which employs a volume buffer for 3D scene representation, offers advantages over surface graphics: It is viewpoint independent, insensitive to scene and object complexity, and suitable for the representation of sampled and simulated data sets. Moreover, geometric objects can be mixed with these data sets. Volume graphics supports the visualization of internal structures and lends itself to the realization of block operations. constructive solid geometry modeling, irregular voxel sizes, and hierarchical representation. Volume graphics has problems associated with the volume buffer representation, such as discreteness, memory size, processing time, and loss of geometric representation. However, these problems are similar to those encountered when raster graphics first emerged as an alternative technology to vector graphics, and they can be alleviated in similar ways. A table in the article comparing surface graphics and volume graphics exhibits striking similarities to another table comparing vector graphics and raster graphics. This implies that volume graphics, echoing the earlier evolution in 2D graphics, may supersede surface graphics for handling and visualizing volumes as well as for modeling and rendering synthetic scenes composed of surfaces.