Unable to add rings.

[Krypton]

If I turn the time step way down (1 minute to 1 hour) I can add rings and they appear correctly.  But if I turn the time step up, they "bloom" and expand until they disappear.

If I add the rings while the time step is turned up to, say, 1 day or more, the rings appear as a disperse ring, almost like an asteroid belt, centered on the sun, and this too expands quickly and disappears.

[Darvince]

It's because gravity is calculated once for how long a timestep is. So like, if you have the time step at 1 hour gravity will be calculated once an hour (in the simulation). Switching to RK4 would calm this effect down as it calculates gravity 16 times per time step, so it would calculate it about once every 3 minutes of simulation time if you had it set the time step to an hour.

[Krypton]

Understood.  I surmised it was a bug, but what I was asking (and perhaps I should have been more clear) was is there a way to work around it, or is it being worked on for next version?  I think I found my answer in another thread.

[Darvince]

Open the left-hand panel and switch to RK4/Runge-Kutta 4 gravity simulation.

[Krypton]

I don't see anything like that in the left hand panel.  Or even the right hand panel.  What is it?

[Krypton]

Oh I found it.  I'll give that a try.

[Krypton]

No luck.  When I move the time step up to 1 hour, the rings disappear.  Thanks for the advice though.

[vh]

you have to keep the time step down; no matter which intergration method you use if the time step goes to high it's like trying to draw a circle with straight lines and it doesn't work. Just keep the timestep lower.

[Krypton]

Yeah, I can see that.  I hope they can find a way to have ringed planets with higher time steps.

[smjjames]

Yeah, I can see that.  I hope they can find a way to have ringed planets with higher time steps.

That should be fixed in Ubox 3 since they found a way past the problem of moons limiting the time step or otherwise they get thrown out of orbit (or slam into the parent object). So, you will be able to run Ubox 3 at almost any time step you'd like.

[Dan Dixon]

So, you will be able to run Ubox 3 at almost any time step you'd like.

If you use one of the adaptive integrators (new in v3) then it will automatically subdivide the set time step into smaller steps until the step size becomes stable, but this still requires massive computation... so while you can run any time step you like, the frame rate may plummet to something unsatisfactory.

[smjjames]

So, you will be able to run Ubox 3 at almost any time step you'd like.

If you use one of the adaptive integrators (new in v3) then it will automatically subdivide the set time step into smaller steps until the step size becomes stable, but this still requires massive computation... so while you can run any time step you like, the frame rate may plummet to something unsatisfactory.

At least moons won't force us to use time steps on the order of days or hours just to keep them in a stable orbit.

[Krypton]

Nice to know it's an issue being worked on and not just me doing something noobish.  Thanks for the response.  And looking forward to whatever improvements are in the works.