GDC Physics Tutorial

The slides for Erwin Coumans’ Game Developers Conference Physics Tutorial on parallel SPU physics are available for download and on-line here:

http://www.bulletphysics.com/Bullet/wordpress/uncategorized/gdc-2008-physics-tutorial-on-parallel-game-physics-for-spu

They cover parallelizing a typical collision detection and rigid body dynamics pipeline and provide links for further reading.

Thanks for Erwin for the link.

Hardware-Aware Analysis and Optimization of Stable Fluids

 We perform a detailed flop and bandwidth analysis of Jos Stam’s Stable Fluids algorithm on the CPU, GPU, and Cell. In all three cases, we find that the algorithm is bandwidth bound, with the cores sitting idle up to 96% of the time. Knowing this, we propose two modifications to accelerate the algorithm. First, a Mehrstellen discretization for the pressure solver which reduces the running time of the solver by a third. Second, a static caching scheme that eliminates roughly 99% of the random lookups in the advection stage. We observe a 2x speedup in the advection stage using this scheme. Both modifications apply equally well to all three architectures.

Hardware-Aware Analysis and Optimization of Stable Fluids

Fast Collision Detection for Deformable Models using Representative-Triangles

We present a new approach to accelerate collision detection for deformable models. Our formulation applies to all triangulated models and significantly reduces the number of elementary tests between features of the mesh, i.e., vertices, edges and faces. We introduce the notion of Representative-Triangles, standard geometric triangles augmented with mesh feature information and use this representation to achieve better collision query performance. The resulting approach can be combined with bounding volume hierarchies and works well for both inter-object and self-collision detection. We demonstrate the benefit of Representative-Triangles on continuous collision detection for cloth simulation and N-body collision scenarios. We observe up to a one-order of magnitude reduction in feature-pair tests and up to a 5X improvement in query time.

Fast Collision Detection for Deformable Models using Representative-Triangles