Universe Sandbox

Universe Sandbox => Universe Sandbox | Support & Bugs => Topic started by: epic_universe_creator123 on October 24, 2014, 11:18:56 PM

Title: if time goes to fast everything spins out of orbit.
Post by: epic_universe_creator123 on October 24, 2014, 11:18:56 PM
I was playing around waiting for my planet to orbit (which would take 100,000 years ) when I decided to speed the clock up to 10,000 years p/s suddenly ALL my planets spun out of the sun's orbit and disappeared into space. FIX IT!!!! >:(
Title: Re: if time goes to fast everything spins out of orbit.
Post by: Xriqxa on October 24, 2014, 11:56:23 PM
Wow, much aggression.png

The problem here is that you're putting the timestep WAY too fast. After a while, orbits will decay if you have a big timestep, since the faster time goes, the less calculations the simulation can make, therefore orbits go crazy.
Title: Re: if time goes to fast everything spins out of orbit.
Post by: C7 on October 27, 2014, 08:39:31 AM
If you hover over the time controls, you can change the slider that determines the accuracy of the simulation.

What's happening is that simulation is accumulating enough error at that timestep that it destabilizes the orbits, and everything goes flying off into space. You can either reduce the timestep (and therefore the error), or increase the accuracy (which slows down calculation time). You can also try using another integrator, as each one of them behaves differently in these kinds of situations.

TLDR version : This is a fundamental issue with gravity solvers, and we're trying to balance speed vs accuracy here.

https://www.youtube.com/watch?v=IJ2MhXUDZ6o