Gravity Simulator
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Message started by looseskrewz on 04/21/07 at 16:13:37

Title: A few thoughts
Post by looseskrewz on 04/21/07 at 16:13:37

I was thinking of a few features that may be good for the simulator (if they don't already exist)

1. A way to display just one type of object.

Example: I have a system with asteroids, planets...etc It would be cool to be able to show just the planets, or just the asteroids. (or even select by color, or by +/- mass of object)

2. A way to display just the bodies that have already had collisions.

3. A measureing tool so you can drag from one object to the next to find the distances between both objects.

4. A radial 'pull tool' that would show the effect of the objects gravity at a given distance from the object.

Just some thoughts, maybe I'm a strange ranger or something, but those type of tools would be very useful in my line of study.

Again, I'm new here, so don't pay much mind. :)

Thanks for reading,


Title: Re: A few thoughts
Post by Tony on 04/21/07 at 23:27:18

There's some indirect ways to do some of the things you want:

1.  There's no automatic way to do this, but if you want to do it manually, you can set an object's size to a negative number, and it will not plot it, but it will consider its gravity in the simulation.  It should just take you a minute or two in the menu Object > Edit Object interface to go through each object, add a negative sign to its size and press Apply.  I think this only works in the Beta Version.

2.  In the Moonbuilder scenerio, each of the moonlets start out with the same mass.  So if you want to see which have had collisions you can open the menu Objects > Edit Objects interface, click on the object field, and use your mouse scroll button to quickly run through the objects.  The ones that are twice as massive as the original objects have suffered one collision.  The ones that are three times as massive have suffered two collisions, etc.  Additionally, the Beta version should create a file called collision.dat which gives you a log of collisions.  You can use this in conjunction with the AutoSave feature in the file menu.  So if you make a simulation that runs for thousands of years, and you return tommorow morning to see that an object is missing, you can review the collision.dat log to see when it collided, then open the closest previous AutoSaved simulation and watch the collision.

3.  menu View > Distance and Velocity Box.  You can open as many of these as you want.  Just choose the two objects you want the distance between.  Additionally, you can export your data for use in Excel.  That's why you see so many Excel-generated graphs in this forum.  If you export Rx, Ry, and Rz (in the Beta version you have to choose them, in 2.0, it exports them for you), then in your spreadsheet you can compute the distances using the Pothagarean theorum.  Assuming object 1 has its Rx, Ry and Rz in colums A,B,&C, and object 2 has its Rx, Ry and Rz in colums i, j, &k :  "=sqrt((a1-i1)^2 + (b1-j1)^2 + (c1-k1)^2)"

4.  I'm not quite sure what you're asking here.  Do you want to know the acceleration caused by gravity for an object at a given distance?

Title: Re: A few thoughts
Post by looseskrewz on 04/22/07 at 07:05:06

Great, thanks for the info, I guess you already had this stuff figured out.

As for #4, I guess I was looking for something where you could click on an object, and then drag to another object, and find out how much 'gravity pull' the first object is having influence on the second object...if any at all.

Scenario...I made a 'gas cloud', and I sat there waiting for two particles to collide, every time I would see two that looked close, I would zoom to that point, and wait again.

...but I wasn't sure at any moment if the particles were close enough together to start an interaction with each other and collide.

If my parents ever knew I stared at tiny pixels on a screen.
My wife and daughter already think I am a weirdo. :)

Anyhow, did I explain properly?.

Title: Re: A few thoughts
Post by abyssoft on 04/22/07 at 09:24:29

If I understand LS correctly he wants a Gravitation vector display for 2+ objects including data.
This could be done in another tool box.

Button to select which objects are to be involved
Drop down which selects which object of the selected set
Display section that shoves the gravitational vector in terms of direction and a normalized length based on sum acceleration due to gravitation, ( Log10(Acceleration) +50)/2+10 is the length in pixels.
this will handle from a net acceleration of 1e-59 [Less then the acceleration caused by a 1kg object on 2nd object 1 lyr away] to c expressed as acceleration, this should never be actually reached (!!! big Idea might want to add a check for this in the calculation proceedure to prevent object being accelerated faster then c in High time step sims.!!!)

Lable section Showing Direction Theta, Sigma, and Acceleration m/s^2

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