Interactive Ray Tracing of Distance Fields

Distance field is a flexible surface representation used in many applications. We study the algorithms for direct rendering of distance field surfaces representation via ray tracing in interactive frame rates. To accelerate the ray tracing we represent the distance fields by sparse block grid data structure. We compare the visual quality and the computation time for different methods of ray-surface intersection test and for surface normal estimation. We present a technique to accelerate the computation for primary rays from camera by projection. We also describe another technique for faster computation of shadow rays via volumetric occlusion. We show the results on four scenes of different complexities.