Abstract
In usual cases, most cells in a volume data set are empty, and this means almost all rendering time is wasted simply in traversing the empty cells along the viewing rays in raycasting computation. To accelerate raycasting, all the non-empty cells are sandwiched by a pair of pre-calculated depth maps, and 3DDDA is only applied to the interval. Also a shadow map is used to eliminate 3DDDA process from shadowing. Additionally, we study and compare some cubic root solvers necessary for intersection tests of trilinearly interpolated isosurfaces.
