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Interface problems (and general usage questions) (Read 2398 times)
EDG
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Interface problems (and general usage questions)
10/08/06 at 21:41:26
 
I tried using GravSim a while back with no success, but I just tried it again and got something working finally!
 
However, the interface is still a problem, it's really user-unfriendly IMO. But to try to be a bit constructive with it, here's what I don't like about it - in the hope that maybe Tony can improve it a bit...  
 
1) when you hit "new", you start off really close to the default object. I think starting at least 1 AU from it would make more sense, since most people are probably going to be putting planets or stars around a central object orbiting at that kind of distance.  
 
2) when entering a new object, "size" is the diameter in km. But radius is used more often in calculations and datasheets, not diameter. It's a bit of a pain to have to keep multiplying radii by two to enter them - so how about replacing this with "radius"?
 
3) the really big pain is that it seems that you can't edit the layout of a system. If I'm entering a new object and have the option to set its longitude of ascending node, argument of pericentre, and mean anomaly there then I should darn well be able to edit those directly when I'm editing an object! Instead it seems I have to delete the object and re-enter it again.  
 
This is a showstopper really - if I want to do another run with a saved system but want to put one or two objects in different places on their orbits as initial starting conditions then I just can't do that without having to convert to XYZ coordinates and then figure out where their new starting positions should be, which is a horrendous pain. And while deleting and re-entering is easier, it's still a pain. Can we have an option to edit the object's starting position on its orbit (in degrees) directly please?  
 
In fact, I'd just kill for a simple way to edit the starting parameters in general without having to re-enter them again. It'd be great if they could be saved to a text file and edited manually and then just reimported from there.  
 
4) In fact, specifying a starting location for an object isn't exactly intuitive. AFAIK the mean anomaly can tell you where the object is on its orbit but it's not the most obvious thing to figure out. An option to just specify an angle between 0 and 360 relative to a reference line would be a lot simpler and a lot more intuitive too.  
 
5) the orbit lines that are drawn are quite thick - as a result things can get messy real quick if there's a lot of orbital change going on - some way to make them thinner would be nice.  
 
6) Not entirely sure what to do with the output. If I plug some bodies into the program, let it run and end up with one body left, how can I get its final orbital parameters out of the program? I've tried autosaving a data file but the textfiles that are supposed to be generated are nowhere to be found.  
 
Sorry to start off with criticisms, but the interface is currently a pretty significant obstacle to being able to use the program effectively - which is a pity because once you get through those it's actually rather useful. I really hope that there are plans to improve the interface soon.
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Tony
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Re: Interface problems (and general usage question
Reply #1 - 10/10/06 at 11:19:40
 
Quote:
Sorry to start off with criticisms, but the interface is currently a pretty significant obstacle to being able to use the program effectively

I appreciate the criticisms more than the praise because they can lead to improvements.
Quote:
1) when you hit "new", you start off really close to the default object. I think starting at least 1 AU from it would make more sense, since most people are probably going to be putting planets or stars around a central object orbiting at that kind of distance.

If you're working with exosolar planets, you may want to be close.  But everyone will have their own opinion as to what a "New" simulation should look like.  I don't use the "New" option that much.  I prefer to keep a few simulations that I consider starting points.  For example, if you want to start out with a single solar mass object and a screen zoomed out to a few AU, just create that once and save it.  Then instead of using File > New, use File > Open and choose your own custom New simulation.
Quote:

2) when entering a new object, "size" is the diameter in km. But radius is used more often in calculations and datasheets, not diameter. It's a bit of a pain to have to keep multiplying radii by two to enter them - so how about replacing this with "radius"?

I agree with you, radius would be nicer.  The next version will give you a choice between radius and diameter.
 
Quote:

3) the really big pain is that it seems that you can't edit the layout of a system. If I'm entering a new object and have the option to set its longitude of ascending node, argument of pericentre, and mean anomaly there then I should darn well be able to edit those directly when I'm editing an object! Instead it seems I have to delete the object and re-enter it again.

You're not the first person to request this.  I may make a new interface that's a combination of the Edit and Create interfaces.
 
Quote:
In fact, I'd just kill for a simple way to edit the starting parameters in general without having to re-enter them again. It'd be great if they could be saved to a text file and edited manually and then just reimported from there.

I'm not quite sure what you have in mind here.
Quote:

4) In fact, specifying a starting location for an object isn't exactly intuitive. AFAIK the mean anomaly can tell you where the object is on its orbit but it's not the most obvious thing to figure out. An option to just specify an angle between 0 and 360 relative to a reference line would be a lot simpler and a lot more intuitive too.
I agree with you that mean anomoly is not the most intuitive orbital element, but it is the most widely used among astronomers, and if you see orbital elements published for an object, mean anomoly is almost always used to specify location.  What you're asking for is called True Longitude.  I'll look into it and see if it can be used as a starting parameter without causing ambiguity.
 
Quote:
5) the orbit lines that are drawn are quite thick - as a result things can get messy real quick if there's a lot of orbital change going on - some way to make them thinner would be nice.

In Preferences, choose minimum object size and set it to 1 if it isn't already.  It would be nice if it could go even thinner than this.  One day I'm going to completely re-work the graphics, so I don't want to spend too much time improving the existing code.
Quote:

6) Not entirely sure what to do with the output. If I plug some bodies into the program, let it run and end up with one body left, how can I get its final orbital parameters out of the program? I've tried autosaving a data file but the textfiles that are supposed to be generated are nowhere to be found.
 
I'm not sure why it isn't generating the .txt file for you.  But this area has already been much improved for the new version.
 
Thanks for your comments.
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EDG
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Re: Interface problems (and general usage question
Reply #2 - 10/10/06 at 15:30:32
 
[quote author=Tony  link=1160368886/0#1 date=1160504380]For example, if you want to start out with a single solar mass object and a screen zoomed out to a few AU, just create that once and save it.  Then instead of using File > New, use File > Open and choose your own custom New simulation. [quote]
 
I guess that'll work Smiley
 
 
Quote:
I agree with you, radius would be nicer. The next version will give you a choice between radius and diameter.

 
Which reminds me, what's the development status of the program? Is it being actively developed now, any ETA on a next version or patch?  
 
Quote:
You're not the first person to request this. I may make a new interface that's a combination of the Edit and Create interfaces.

 
I'd strongly suggest that the new interface has options to edit the angular parameters of the orbit, because right now it's pretty much impossible to just move an object a few degrees around its orbit without having to delete and recreate it from scratch.  
 
 
Quote:
I'm not quite sure what you have in mind here.

 
I mean to have a text file with the starting parameters, corresponding to what you enter when you Create New Object. It could be as a simple list for each object that gets read in (and can be saved as such) when you want to start a new instance of the simulation, and can also be manually edited.  
 
So you'd have the file set up something like this:
 
start date
timestep
radius      errorbar
mass       errorbar     units
semimajor axis    errorbar    units
long of pericentre      errorbar
eccentricity    errorbar
inclination       errorbar  
and so on.  
 
The program could also output these files directly (very useful when you have hundreds of planetesimals or asteroids), and you could then tweak one or two in a text editor.  
 
I'm sure the gsim files can be manually edited too, but I can't tell how the numbers in there relate to what's entered into the program, so it's not easy to edit parameters directly in the gsim file to tweak the starting conditions.  
 
Quote:
I agree with you that mean anomoly is not the most intuitive orbital element, but it is the most widely used among astronomers, and if you see orbital elements published for an object, mean anomoly is almost always used to specify location. What you're asking for is called True Longitude. I'll look into it and see if it can be used as a starting parameter without causing ambiguity.

 
Thanks.
 
Quote:
I'm not sure why it isn't generating the .txt file for you. But this area has already been much improved for the new version.

 
I'm not sure either, I'll give it another go later on.  
 
I have some other questions about some specific setups, but I'll ask those later on too.  
 
Thanks!
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