Abstract
Figure 1: Cloth draped over a sphere. A coarse triangle mesh with 5100 vertices (left) is used for collision handling on the CPU while a high-resolution regular grid with 230k particles is simulated on the GPU to get fine wrinkles (middle). The right image shows a close-up view of the high-resolution mesh used for rendering. Today most cloth simulation systems use triangular mesh models. However, regular grids allow many optimizations as connectivity is implicit, warp and weft directions of the cloth are aligned to grid edges and distances between particles are equal. In this paper we introduce a cloth simulation that combines both model types. All operations that are performed on the CPU use a low-resolution triangle mesh while GPU-based methods are performed efficiently on a high-resolution grid representation. Both models are coupled by a sampling operation which renders triangle vertex data into a texture and by a corresponding projection of texel data onto a mesh. The presented scheme is very flexible and allows individual components to be performed on different architectures, data representations and detail levels. The results are combined using shader programs which causes a negligible overhead. We have implemented CPU-based collision handling and a GPU-based hierarchical constraint solver to simulate systems with more than 230k particles in real-time.
![Gpu Gpu](/uploads/1/2/4/7/124794771/252540239.png)
Real-time constraint required by VR. Nowadays, collision detection is decomposed in two phases: broad-phase and narrow-phase. The broad-phase takes as input the whole set of objects present in the simulation, and output a list of pairs of objects that might be in collision with simple tests (with bounding volumes).