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 view windows (60, 62, 64), each view window (60, 62, 64) corresponding to one of a set of predetermined voxel types, each voxel type including a voxel value selection specifying 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, selectively add each voxel value to a corresponding pixel value of one of the two-dimensional projection images shown in view windows (60, 62, 64) of the plurality of view windows corresponding to the classified voxel type; concurrently generate two-dimensional projection images corresponding to the view windows (60, 62, 64) populated by processed voxels belonging to each image's voxel value selection specification; wherein the each processed voxel is masked from appearing in the remaining view windows of the plurality of view windows (62, 64), and differently colorize the two-dimensional projection image corresponding to each of the view windows (60, 62, 64) in accordance with a separate color channel of a color space. at least one processor programmed to: define a plurality of view windows (60, 62, 64), each view window (60, 62, 64) corresponding to one of a set of predetermined voxel types, each voxel type including a voxel value selection specifying 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, selectively add each voxel value to a corresponding pixel value of one of the two-dimensional projection images shown in view windows (60, 62, 64) of the plurality of view windows corresponding to the classified voxel type; concurrently generate two-dimensional projection images corresponding to the view windows (60, 62, 64) populated by processed voxels belonging to each image's voxel value selection specification; define a plurality of view windows (60, 62, 64), each view window (60, 62, 64) corresponding to one of a set of predetermined voxel types, each voxel type including a voxel value selection specifying 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, selectively add each voxel value to a corresponding pixel value of one of the two-dimensional projection images shown in view windows (60, 62, 64) of the plurality of view windows corresponding to the classified voxel type; concurrently generate two-dimensional projection images corresponding to the view windows (60, 62, 64) populated by processed voxels belonging to each image's voxel value selection specification; wherein the each processed voxel is masked from appearing in the remaining view windows of the plurality of view windows (62, 64), and differently colorize the two-dimensional projection image corresponding to each of the view windows (60, 62, 64) in accordance with a separate color channel of a color space.