Interactive Semi-Transparent Volumetric Textures

Volumetric textures are often used to increase the visual complexity of an object without increasing the polygon count. Although it is much more efficient in terms of memory to store only the volume close to the surface and to determine the overall shape by a triangle mesh, rendering is much more complicated compared to a single volume. We present a new rendering method for volumetric textures which allows highest quality at interactive rates even for semi-transparent volumes. The method is based on 3D texture mapping where hundreds of planes orthogonal to the viewing direction are rendered back to front slicing the 3D surface volume. This way we are able to correctly display semi-transparent objects and generate precise silhouettes. The core problem is to calculate the intersection of prisms formed by extruding the triangles of the mesh along their normals and the rendering planes. We present two solutions, a hybrid and a purely hardware-based approach