Multicoll

Multicoll is a concept in computational physics and computer graphics describing the handling of multiple simultaneous collisions within a single simulation step. It refers to the detection and resolution of contact events that involve more than two bodies at once, as opposed to treating each collision independently. In dense or dynamic scenes, multiple contacts can occur nearly simultaneously, creating a contact manifold that must be resolved coherently to avoid interpenetration and instability.

Approaches to multicoll involve grouping contacts into a cohesive set and solving the resulting constraints that govern their interaction. Techniques used in practice include sequential impulse solvers with contact grouping, constraint-based solvers that formulate a linear complementarity problem, and position-based dynamics methods that project penetrations while maintaining stability. Multicoll problems can suffer from degeneracy, inconsistent constraint ordering, and energy drift if not handled carefully; robust implementations often employ warm-starting, stabilization terms, and regularization.

Applications of multicoll span real-time physics engines, where realistic interaction among many objects is important for games and robotics simulators, as well as offline simulations in fields such as granular flow and crowd dynamics. The term multicoll is not a formal standard but rather a descriptive label for the class of problems and methods that address simultaneous or multi-body contact resolution in dynamic systems. See also collision detection, contact resolution, rigid body dynamics, and continuous collision handling.