Pen-and-Ink for BlobTree Implicit Models

New techniques are presented for rendering complex hierarchical skeletal implicit models in several pen-and-ink styles. A particle system is employed to find interesting areas on the surface and perform stroke stylization guided by local shape features. Interesting areas include silhouette strokes and lines following local shape features, such as those caused by CSG junctions. Hidden line removal is performed either by applying a surfel technique for rapid prototyping or, more accurately, by using ray tracing. Examples drawn from simple to complex models illustrate the capabilities of our system.