#rigid-body-dynamics

vsim_d is the physics daemon that flies Vayu's real firmware in software. A field report from the seam where Newton–Euler rigid-body mechanics meets RK4, quaternion drift, impulse contact, and a hard-real-time loop — including the cleanest way I know to turn a triangle mesh into an inertia tensor, and the bugs where the physics was right but the numerics (or the systems) lied.