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11/21/17 at 13:28:42
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new beta version (Read 56996 times)
EDG
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Re: new beta version
Reply #15 - 02/25/09 at 16:02:25
 
Quote from Tony on 02/25/09 at 15:27:37:
It doesn't check for close encounters with each iteration.  Rather it is controlled by the "Do Events" interval in the preferences menu.  This is set to 50 by default, but you may want to slow it down to 5.

 
This is great Tony, thanks Smiley. But what does the part I quoted mean exactly?
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Re: new beta version
Reply #16 - 02/25/09 at 18:28:51
 
Since the process of determining whether any objects violate the minimum distance set by the user takes a bit of time, rather than do it once per time step, it is only done once every several time steps.  This is determined by the "Do Events" box in the Preferences menu.  "Do Events" tells Gravity Simulator how often to return control of the computer back to Windows.  If it is set too high, the program becomes non-responsive.  If set too low, it slows down the simulation.  50 is the default.  That's often enough that your keyboard and mouse remain responsive, and seldom enough that it doesn't significantly slow down the program.  But even lowering this number as low as 5 is almost as good as 50.  Since this number now determines how often close encounters are checked for, lowering it from the default 50 might make sense.  Or perhaps I will sepeatate them in a future version.
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Re: new beta version
Reply #17 - 02/26/09 at 19:04:17
 
It's brilliant watching my asteroid belt with the new beta... I've got it going at 65k with the trails off, and every now and then it looks like it lurches into "bullet time" when it's doing a close encounter at 1024 Smiley.
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Re: new beta version
Reply #18 - 03/18/09 at 00:13:18
 
Would be nice if it computed orbital elements barycentrically rather than relative to the reference object. The elements of a circumbinary planet are gibberish at the moment.
 
 
 
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Re: new beta version
Reply #19 - 03/18/09 at 12:21:50
 
Quote from chemist on 03/18/09 at 00:13:18:
Would be nice if it computed orbital elements barycentrically rather than relative to the reference object. The elements of a circumbinary planet are gibberish at the moment.

 
That's on my "to do" list.  Welcome to the forum!
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Re: new beta version
Reply #20 - 03/18/09 at 18:48:20
 
Excellent. It would have to be optional because I think you'd have the opposite problem for satellites that orbit one member of a binary. Another thing: if you try to create an object in a small orbit around the barycenter (unphysical) it shoots off at tremendous velocity!
 
Some other suggestions.
(1) Hill sphere display. Add an option to display objects' Hill spheres relative to their reference, maybe as a translucent shading.
(2) Programmable actions. eg if an object's semimajor axis or eccentricity exceeds a threshold, delete it. This would be handy when testing orbit stability with flocks of test particles.
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Re: new beta version
Reply #21 - 11/22/09 at 13:29:12
 
This version allows you to use either "." or "," when editing numbers in the Edit Object interface, to make it compliant with non-English settings.
http://orbitsimulator.com/gravity/beta/GravitySimulatorBeta2009Nov22.exe
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Re: new beta version
Reply #22 - 11/23/09 at 13:35:52
 
http://orbitsimulator.com/gravity/beta/GravitySimulatorBeta2009Nov23.exe
 
I think this fixes all the comma/dot issues.  Let me know if it works for you.  It also includes a new "Edit Objects" box that allows you to edit by orbital element.
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Re: new beta version
Reply #23 - 08/19/10 at 20:43:21
 
Tony - have there been any more updates to the program recently? The most recent beta I've got is the 2009Nov23 one. Is that the one you're still using at home, or are you using a super-seekrit advanced version with lots more cool stuff? Wink  
 
And what version is available for download on the main gravity simulator site - is that still the original version?
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Re: new beta version
Reply #24 - 08/20/10 at 07:06:19
 
Good point Mal .  
Something I want to simulate once is the migration of the gas giants in early times . Herefor I need the possibility to add the gas drag as a force to smaller bodies . Would be fun to have this feature added ...
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Re: new beta version
Reply #25 - 08/20/10 at 19:43:37
 
If it were super-seekret I wouldn't tell you  Grin  I'm still using Nov2009.  I thought I'd get around to doing some coding this summer, but I cleaned out the garage and painted the house instead.
 
You can migrate things already.  In Autopilot, choose "Continuous Orientation", select your object, and choose "Orient Retrograde" to make an object migrate in.  Then choose "Thrust", select your object, and choose a super-slow acceleration.  Then watch as it spirals in towards the Sun.
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Re: new beta version
Reply #26 - 12/15/10 at 00:40:41
 
Just looking over the thread, and now I'm wondering - if we downloaded the latest beta, should we also have downloaded the latest version of the "codeoptomizer.dll" (sic) and resume.gsim files from earlier in the thread too? When I last updated my windows OS to windows 7 I got the latest beta but I don't think I downloaded the dll and gsim.  
 
This is why I think it would be nice if the original Installer file available from the download page was updated with the latest versions of the new files...!
 
(also, the spelling obsessive in me would like to point out that it should be "codeoptimizer.dll" (if you're spelling it in american), not "codeoptomizer.dll"!)
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TEST MASSES, ORBITAL PLANE ROTATION
Reply #27 - 01/20/11 at 11:11:43
 
Two things I'd like to see in a future version:
 
1. TEST MASSES. These would react to gravity but produce none of their own.
 
Why not just make a 1 kg object; isn't that the same thing? Well, for ONE object, yes, but say you want THOUSANDS of objects. The algorithm seems to compute gravity between every object in the system, no matter how small... generally a good thing, but as the number of objects rises, the number of calculations required rises according to
x-1
Σ n
n=1

where x is the number of objects in the simulation.
 
But if we could make test masses with no gravity of their own, the number of calclations becomes
x-1
Σ n
n=m

where x is the total number of objects and m is the number of test masses.
 
So let's say you want to simulate the rings of Saturn and its large moons, considering the ring particles to be of negligible mass. You put in Saturn and say its dozen largest moons and 2000 ring particles and let 'er rip. Currently this would require 2025078 gravitational calculations per frame (and would probably crash the program). But if the ring particles are test masses with no gravity of their own, the number of calculations drops by almost 99% to only 26078 per frame.
 
2) Rotating frames confined to rotation IN THE ORBITAL PLANE. For example, I'd like to look at the dynamics of Trojan asteroid inclination with respect to Jupiter, so I'd like to look at the rotating frame obliquely. Currently, the axis of rotation is always orthogonal to the screen.
 
Overall I love this program, but as with anything else, there are things I want to do that it can't... but I think both of the above are fairly easy to implement. (If you want to throw me some source code, I'll happily have a crack at it.)
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Re: new beta version
Reply #28 - 01/20/11 at 21:20:23
 
Hi.  Welcome!  You seem to have mastered the program pretty well so far.  I assume you are using the latest Beta version.  The program already has test masses.  Just make masses with 0 kg, and it will skip the computations of that object accelerating all the other objects.
 
One day I'm going to redo the graphics entirely.  I've been saying that for a while, but when I do, I plan on allowing you to adjust the viewing angle of the rotating frame.  Thanks for the suggestions!
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Secondary color for objects
Reply #29 - 01/25/11 at 16:42:44
 
It would be nice to be able to define a secondary color for objects when z is negative. This is already a common practice in orbit illustration to show the longitude of nodes, as in this picture from the Wikipedia article on Ceres:
 
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