Read description for more about this update! What is this? This is a demo of how a combined Rigidbody is detected correctly and buoyancy is working very nicely now. Apart from this, several layers of objects underwater are detected but this video doesn't show it.
This has been massive. I've had to tackle with several Unity bugs regarding RaycastCommand and others that made it impossible to make it faster. I finally managed to run this very expensive process with less than 0.5ms (50k raycasts, and long processing tasks) for this example. Obviously depending on how well you optimize your surface and the resolution, number of detections, number of colliders overlapped, etc. Extremely jobified and using a lot of hacks to jump over Unity's bugs. It's been nearly one year of development and I'm getting to the end... very soon! Stay tuned