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Per Erin Catto (Box2D), CONSTRAINT-BASED simulation solves contacts and joints using which approach?
AParticle swarm optimisation per contact pair
BDirect LU factorisation of the contact matrix
CGenetic algorithm over candidate impulses each step
DIterative impulse solver (Gauss-Seidel sweep)
Answer & Solution
Correct answer: D. Iterative impulse solver (Gauss-Seidel sweep)
Catto Box2D solver: sequential impulse / projected Gauss-Seidel, iterating over constraints multiple times per step. Fast, robust, and stable for stacking.
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