The trick is to only apply positive impulses and discard negative ones: https://github.com/IainWinter/IwEngine/blob/6f94a946a90db989412ff29320a0baeca7a5f8cb/IwE

The trick is to only apply positive impulses and discard negative ones: https://github.com/IainWinter/IwEngine/blob/6f94a946a90db989412ff29320a0baeca7a5f8cb/IwEngine/src/physics/Dynamics/ImpulseSolver.cpp#L26 https://github.com/IainWinter/IwEngine/blob/6f94a946a90db989... Things will sort themselves out over several frames. Objects might sink into each other a bit, but that is generally not very noticeable unless you make huge piles of spheres. However, it might quickly become a problem in 2D, since you only need a quadratic number of objects to get a "critical" pile, compared to a cubic number of spheres in 3D.