I was thinking of resolving collisions the way you would simulate boyancy: by applying a force and torque from a certain point (the center of boyancy, the cente

I was thinking of resolving collisions the way you would simulate boyancy: by applying a force and torque from a certain point (the center of boyancy, the center of the subvolume that is submerged), calculated by pressures (i.e., which areas of the object "dip into" the other object). This should also fix the bouncy jitter that happens when objects lie flat on their face, without needing a "ground" state. Imagine a bug coming from the ground state design: an object is grounded onto another object, but that other object slowly tilts. The grounded object never slides off, but remains suspended in air.