Rapid exploration of curvilinear grids using direct volume rendering

Fast techniques for direct volume rendering over curvilinear grids (common to computational fluid dynamics and finite element analysis) are developed. Three new projection methods that use polygon-rendering hardware for speed are presented and compared with each other and with previous methods for tetrahedral grids and rectilinear grids. A simplified algorithm for visibility ordering, based on a combination of breadth-first and depth-first searches, is described. A new multi-pass blending method is described that reduces visual artifacts that are introduced by linear interpolation in hardware where exponential interpolation is needed. Visualization tools that permit rapid data banding and cycling through transfer functions, as well as region restriction, are described