Hierarchical Penumbra Casting

We present a novel algorithm for rendering physically-based soft shadows in complex scenes. Instead of casting shadow rays, we place both the points to be shaded and the samples of an area light source into separate hierarchies, and compute hierarchically the shadows caused by each occluding triangle. This yields an efficient algorithm with memory requirements independent of the complexity of the scene. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Three-Dimensional Graphics and Realism]: Shadowing

• Type: Journal
• Year: 2005
• Where: CGF
• Authors: Samuli Laine, Timo Aila
• Keywords: Area Light Source, CGF 2005, Physically-based Soft Shadows, Separate Hierarchies