Hyperion appears jumpy

[rigelan]

I'm not sure if this is a feature request or a bug or just performance issues.

I was flying through the Sol System and I was on a mission to patrol hyperion, one of saturn's moons.

I could get very close, within a 10 miles of the surface easily. But getting closer than that was difficult. The problem is that hyperion moves very fast in relation to 'static space', and it updated its position every half a second or so. So while I would get a 1/2 kilo closer to it, its position would be reupdated a half second later so that it jumped another 3/8 kilo further away. It wasn't smooth at all because it was so fast, and the system wasn't updating fast enough.

This could either be:

1. The Sol system just has too many objects in it so it won't update too fast.
2. There is a hard number written in the code as to how fast the positions of the planets are updated.

The problem:
Increasing the number of times the position is updated per second is probably just one more taxing item on the processor. This would also cause all the other positions to be updated more often as well.

My computer isn't fast, but it isn't slow either, I have an Athlon 1800 & MX440, the performance should be better.

I should go in again and see if hyperion is jumpy again. If it isn't, then it might have been a fluke, if it is, then it should probably be dealth with.

My thought:

Update the position of the nearer objects more often than the further objects?

I'll go check on hyperion again.

Edit: It is still very difficult, If I want to land, or scan the best bet would be to aim ahead of the planet quite a ways and watch it meet up with you. Hopefully it won't destory you when you take off again.

Edit #2: Maybe the real problem is that I can't match speeds with hyperion w/o spec. It travels about 2 kilos a second, the dochoevsky travels at 340 meters a second. If I have spec on I can get close, but as I get close, the multipler drops, and I slow down and get further away. Its like chasing a ship with spec on, constantly getting closer and further away. Its such an unreal effect, when what should happen is that you get a certain distance away and you remain that distance away. I guess I don't know the best answer to the problem. It certainly isn't to slow down hyperion.

[jackS]

I'm familiar with this problem :-/

The problem isn't actually with the update rate for the moon of Saturn (or any other moon or even orbiting base/satellite). The problem is the disconnect between the update rate for the moon (which has been targetted, hence, higher priority for simulation) and the object it's orbiting around (in this case, Saturn, which is not targetted, and, with the current heuristics, lowest priority, because it's a planet). Thus, once every 5 or 6 seconds or so, Saturn's position is updated, and all of its satellites are yanked into a new position.... most unpleasant.

We can likely remedy this by changing the priority heuristics to take into account whether an object is an orbital parent of the targetted object. However, I haven't looked into the matter enough to figure out whether the pointers are facing in a convenient direction on that tree, or whether a search will be required.

[rigelan]

Huh, I didn't even think of that. Thanks for the information.

[jackS]

Edit #2: Maybe the real problem is that I can't match speeds with hyperion w/o spec. It travels about 2 kilos a second, the dochoevsky travels at 340 meters a second. If I have spec on I can get close, but as I get close, the multipler drops, and I slow down and get further away. Its like chasing a ship with spec on, constantly getting closer and further away. Its such an unreal effect, when what should happen is that you get a certain distance away and you remain that distance away. I guess I don't know the best answer to the problem. It certainly isn't to slow down hyperion.

One aside (not related to the bug itself):

If you set your reference zero velocity vector [home] to be that of a fast moving object (try it with one of the planets, say, Earth, to avoid discussed bug) you'll find that you'll eventually be able to come to a relative standstill with respect to your target (the ships speed governor is relative, it just happens to default to Sun-relative). The orbital velocities are actually toned down quite a bit - relative to Sol, Earth is really moving at ~30Km/sec.