Rapier and three-avbd comparison

Preliminary physics-only measurements on identical box and sphere scenes. Timing waits once per batch (use batch size 1 for serialized latency). A separate replay checks every step and must reproduce the timed final state exactly. The floor target is penetration ≤1% of each body's smallest dimension throughout the replay; The contact target also checks box/box, sphere/box and sphere/sphere overlap using an independent candidate search. Neither establishes overall physical accuracy.

Keep this tab visible. Runs default to 60 lead-in steps and alternate engine order between repeats. Large cases may take minutes and require substantial memory. Both default to four iterations; equal iteration counts represent different amounts of work.