Collision and Proximity QueriesCollision and Proximity Queries

Dinesh Manocha

Department of Computer Science

University of North Carolina

dm@cs.unc.edu

Proximity QueriesProximity Queries

A procedure to compute the spatial relation between objects.

Collision

GDC’03

Proximity QueriesProximity Queries

Geometric reasoning of spatial relationships among objects (in a dynamic environment)

d

Closest Points & Separation Distance

d

Penetration Depth

Collision Detection Contact Points & Normals

Problem Domain SpecificationsProblem Domain Specifications

Model Representations– polyhedra (convex vs. non-convex vs. soups)– CSG, implicits, parametrics, point-clouds

Type of Queries– discrete vs. continuous query– distance vs. penetration computation– estimated time to collision

Simulation Environments– pairwise vs. n-body– static vs. dynamic– rigid vs. deformable

ApplicationsApplications

Robot motion planning Simulation of (dis-)assembly tasks Tolerance verification Simulation-based design Ergonomics analysis Haptic rendering Physics-based modeling and simulation

HistoryHistory

Studied over 4 decades in Computational Geometry Robotics & Automation Simulated Environments Computer Animation Physically-based Modeling

Earlier work: 1970s and 1980sEarlier work: 1970s and 1980s

Algorithms for 2D & 3D intersection computation

Collision checking and avoidance

1990’s: considerable momentum1990’s: considerable momentum

Distance computation between convex polytopes (Gilbert et al. 1998; Lin & Canny’91)

Bounding volume hierarchies (sphere-trees, OBBTrees, k-DOP trees, Shelltrees)

N-body collision checking (sweep-and-prune, grid-based methods)

Collision systems for rigid models (I-Collide, RAPID, V-Collide, SOLID, QuickCD, PQP,….)

1990’s: considerable momentum1990’s: considerable momentum

Distance computation between convex polytopes (Gilbert et al. 1998; Lin & Canny’91)

Bounding volume hierarchies (sphere-trees, OBBTrees, k-DOP trees, Shelltrees)

N-body collision checking (sweep-and-prune, grid-based methods)

Collision systems for rigid models (I-Collide, RAPID, V-Collide, SOLID, QuickCD, PQP,….)

1990’s: considerable momentum1990’s: considerable momentum

Collision and contact computations for Physics-based simulation (Baraff’92; Lin’93; Mirtich’95)

1990’s: considerable momentum1990’s: considerable momentum

Collision checking for virtual environments (Cohen et al.’95)

1990’s: considerable momentum1990’s: considerable momentum

Haptic rendering (Gregory et al.’98; H-Collide)

Last 10-12 yearsLast 10-12 years

Novel algorithms– Discrete vs. continuous collision detection– Penetration depth computation– Deformable models– Self-collisions and breaking objects

Utilize the parallelism in multi-core CPUs and many-core GPUs

Development of Physics engines

Focus of this CourseFocus of this Course

Recent research on collision and proximity queries

Implementation in Game Physics libraries

Recent ResearchRecent Research

Continuous collision detection and penetration depth queries (Young Kim)

Algorithms for deformable, breaking and volume meshes (Sungeui Yoon)

Acceleration using GPU parallelism (Dinesh Manocha)

Game Physics SimulationGame Physics Simulation

Bullet Physics Library (Erwin Coumans) NVIDIA PHYSX (Richard Tonge)