Diierential Volume Rendering: a Fast Volume Visualization Technique for Flow Animation

We present a direct volume rendering algorithm to speed up volume animation for ow visualizations. Data coherency between consecutive simulation time steps is used to avoid casting rays from those pixels retaining color values assigned to the previous image. The algorithm calculates the diierential information among a sequence of 3D volumetric simulation data. At each time step the diierential information is used to compute the locations of pixels that need updating and a ray-casting method is utilized to produce the updated image. We illustrate the utility and speed of the diierential volume rendering algorithm with simulation data from computational bioelectric and uid dynamics applications. We can achieve considerable disk-space savings and nearly real-time rendering of 3D ows using low-cost, single processor workstations for models which contain hundreds of thousands of data points.