1. A system for generating layered two-dimensional projections from a three-dimensional data set of an object, said system comprising: at least one processor programmed to: define a plurality of projection images, each view window corresponding to one of a set of predetermined voxel types, each voxel type including a voxel value selection specifiying one or more ranges in value, classify each voxel along each of a plurality of rays through the data set as one of the predetermined voxel types in accordance with each voxel value with respect to the specified voxel value ranges, and, concurrently generating two-dimensional projection images populated by processed voxels belonging to each image's voxel value selection specification, and shown in view windows.