Breathing Rings?

[tuto99]

I noticed that whenever I add rings to an object and increase the time step, the rings seem to "breathe" and they seem to increase in size and shrink. What is that supposed to mean?

[vh]

the rings appear tobreath because their orbit turns elliptical, or stretched out.
a highly elliptical orbit would be very stretched out while a less elliptical orbit is very close to a circle.
when an orbit it stretched out into a highly elliptical shape (eccentricity), it goes far, and then close from the planet. when the particles in a ring do that at the same time, it looks like the whole ring is getting bigger and smaller at the same time.

the rings become highly elliptical because you have made the time-step higher. this simulator works by simulating the motions of all bodies once per time-step. if you turn up the speed too high, the simulator calculates only once in a while because it has to go so fast and this causes stuff to be inaccurate, which causes orbits to move/be inaccurate/causing them to become elliptical.

[Dan Dixon]

In short, if the rings are "breathing" then the time step is too high. This issue will be mostly resolved in the new version we release later this year.