a) (b) (c) (d) Figure 1: Example of a billboard cloud: (a) Original model (5,138 polygons) (b) false-color rendering using one color per billboard to show the faces that were grouped on each (c) View of the (automatically generated) 32 textured billboards (d) the billboards side by side. We introduce billboard clouds -a new approach for extreme simplification in the context of real-time rendering. 3D models are simplified onto a set of planes with texture and transparency maps. We present an optimization approach to build a billboard cloud given a geometric error threshold. After computing an appropriate density function in plane space, a greedy approach is used to select suitable representative planes. A good surface approximation is ensured by favoring planes that are "nearly tangent" to the model. This method does not require connectivity information, but instead avoids cracks by projecting primitives onto multiple planes when needed. For extreme simplification, our approach combines the strengths of mesh decimation and image-based impostors. We demonstrate our technique on a large class of models, including smooth manifolds and composite objects.
Billboard clouds REF reduces 3D models to representative planes mapped with textures.
Billboard clouds for extreme model simplification
SIGGRAPH '03
Computer Science