Physics synchronization over network

Anton Vatchenko · 2010-10-25T13:10:22

We have a server that has physics processing module (rigid bodies). Need to send minimal data to clients to see the same scene.As I understand, sending positions and orientations is not good because if body moves then client gets about 40 bytes per frame, so maybe 400 bytes per second. It's just for one object. But if there's a hundred?So good solution as I understand is to send position, orientation, linear and angular velocities. So if body has linear movement, nothing is being sent. The problem is when to send? Maybe the solution is to emulate client on server - to store those data and update like pos = pos + vel * dt, quat = ... and check the difference between real position and orientation, and between this client emulation. So if difference is more than 0.1 then update client (send all new data). This is bad with quaternions, because they are not linear and the difference |x1 - x2| + |y1 - y2| + |z1 - z2| + |w1 - w2| will be different on different angles.So what to do?