Fragments

[tkulogo]

When my system becomes unstable, the first indicator is the fragmentation of bodies. Is there an obvious way to find these fragments?

[Jar]

Sorry, I can't think of a good way to locate those right now. We don't put them in the Search panel because that could quickly get out of hand with a lot of fragments, at least with the current way we display objects in that panel. That's an interesting dilemma though, something to consider as we move forward.

[tkulogo]

What I have been doing is switching to the "chart" view, looking along the line of planets, and after 15 minutes or so, I find the fragments. Maybe a switch to turn on fragments in the search panel? BTW, since I have your ear, what's up with the timer's max speed? It's certainly fast, but it totally frags the whole system.

[Jar]

The "Max Speed" in the Timer works the same as manually increasing the Time Step to the point where the icon turns red and you get the message saying the simulation can't run faster with the current settings (if Auto Time Step Limit is turned on). This is an estimate of what is the fastest but still relatively stable time step to run the simulation at. It'll vary depending on the simulation, and its effectiveness will vary depending on what you're trying to simulate. This calculation is also tweakable if you click Sim > More. Check out the tooltips on Auto Limit Time Step, Tuning Profile, and Limit Multiplier (under the Advanced expander) to see how you can adjust this.

There are also some simulation aspects that behave differently at different time steps. Tidal effects are one of these. It's definitely not ideal, but it's also a very challenging problem to solve.

[tkulogo]

In the latest version, it went to almost infinite speed and never generated a "simulation can't run faster" message. I'd try and duplicate it, but I'm running a simulation now. As soon as I get a collision I'll see if I can duplicate what I seen before and make a video of it.

[Jar]

Yeah that sounds like it wasn't working as intended then. Unless you have the "Auto Time Step Limit" turned off, in which case it won't have any real limit (and to be clear, the "can't run any faster" message only pops up if you're trying to manually increase the time step, not when using the Timer).

It would be interesting to know if you had a case where the physics system wasn't able to calculate the required stability for some reason.

[tkulogo]

Here's the result of using the timer set at maximum speed: