Celestia Forums

Hi,

I downloaded the "MainBeltAsteroids.ssc" and put it into the celestia extras folder.
I started Celestia and after 30min Celestia was still loading it.
Is that normal???

The .ssc file is 90mb big.

Must I wait longer?

You'll have to describe your hardware configuration in detail before anyone can guess if that's "normal" for your system.

If "show orbits" is enabled, then it will take a very long time to calculate all of the orbital paths for the thousands of asteroids defined in that Addon. Slower cpus will take longer, of course. Celestia's window won't show anything until it has precalculated all of those paths. They are only calculated once, fortunately, not for every screen update.

30 minutes seems like a very long time . . . How much RAM do you have in you computer?

--Chris

This problem has been discussed before, at http://shatters.net/forum/viewtopic.php?t=9622. I decided to test this again on my new PC. To attempt to speed things up, I overclocked my 4400+ to 2.38 GHz. Note that during the entire process, Celestia is using about 50% of my dual core CPU (100% of a single core).

It took about 1 hr and 35 minutes to load Celestia up with the MainBeltAsteroids.ssc in my extras folder. Celestia was using about 600 MB according to Windows Task Manager. I was getting about 1 fps, where I normally get pretty close to 60 fps. This is w/o orbits enabled. Once I turned on astroid orbits, the Celestia window turned white and not responding, as if it's loading something into memory. Celestia's memory usage slowly climbed into the range of 1.2 to 1.3 GB, where it seems to fluctuate up and down some. After about 55 minutes of this, the Celestia window finally displayed Earth again, with a orange background to it (all the orbits blending together). But when I clicked on the window to do something, it turned white again. It's now been sitting like this for about 20 minutes, and Celestia's memory usage seems to have stopped at 1,287,356 KB, not changing at all, and the Celestia window still white. I'll let it go for a little while longer, but I think it might have died

All stats are in the sig.

Indeed...

I have 3 GB of RAM and just tried loading the file with my 3.2 GHz CPU. After 14 minutes I broke off. So this really smells of "something", at least of a most ineffective loading . If I find time, I'll have a look at the code.


Bye Fridger

Well, it's been 1 1/2 hrs since I last saw anything in my Celestia window, so I've given up. That's too bad. For some odd reason I seem to remember being able to enable all the orbits on my old PC, but maybe I'm thinking of something else. *shrugs*

I think that I've found the problem . . . There's some O(N^2) behavior in the loading of ssc files. That is, the time that it takes to load a new object into a solar system is proportional to the number of objects in that solar system. With a few hundred objects in a solar system, the slowdown isn't noticeable. But if you're trying to load all 233,445 asterodis in MainBeltAsteroids.ssc, well, it starts to be a problem. I'm testing a fix now.

--Chris

that'd be a nice one to fix, definitely

After my change, it takes 36 seconds to load the giant asteroid catalog. That's still a long time, but it's about two orders of magnitude faster than before, and this is after all an enormous amount of data. Once the catalog is loaded, Celestia runs at slide show frame rates. Computing the positions of all those asteroids each frame just isn't going to be fast. Some clever culling algorithm could help, but that's not a project I'm going to undertake right now. When asteroid labels are turned on, the screen is pretty much completely brown, with nearly every pixel covered by label text.

--Chris

Cool . Still, if it means we can see just about every asteroid known to man then it'll be really handy for reference, just to see the orbit distributions . If someone makes a precompiled windows version available of the CVS with this in it can you give me a yell please and I can download it?

BTW, is anyone else amazed by the fact that we know of at least 233,000 asteroids in the main belt?! Anyone have any idea how many more there could be out there? Or have we found most of them now?

We can't have found all of them. I'm sure that most of them are going to be tiny and dark: too dim to see from here.

I've checked in the fix, but I still think it's madness to use this giant asteroid catalog

--Chris

Chris,

does that mean that the Celestia startup is faster now, for all other data files (asteroids, comets, planets and moons, stars, etc) ?

By the way, Since yesterday, I'm unable to update the CVS files on my computer. I get an error after the "Tools" folder trying to update.

Wow...

Here you see the asteroids with the huge number of labels obscuring the sun entirely . See Sedna? (arrow)

Bye Fridger

http://celestiaproject.net/forum/viewtopic.php ... 9175dfff16



fichier.scc => 95Mo