Extruded shapes and patterns are widely used by graphic designers to increase the visual richness and realism of 3D models and virtual environments in general. However, the traditional approach that uses polygonal mesh is inappropriate for real-time rendering, in which, just a limited number of graphic primitives can be processed. Hence the interest of using per-pixel approaches. In this paper, we introduce a new image-based technique for rendering extruded details and shapes. We use a single RGBA texture in which we store a binary shape, its Euclidean Distance Transform (EDT), and the two components of the EDT gradient. The rendering algorithm is based on a ray-tracing like procedure, performed in texture space. The use of the EDT allows skipping empty space and thus, minimizes the number of ray-tracing steps. Per-pixel extrusion mapping produces very convincing results, and runs at interactive frame rates.

Real-Time Rendering, Image-Based Modeling and Rendering, Ray-Tracing in GPU, Mesostructures, Extrusion, Euclidean Distance Transform