# Thread: Plotting Planetary Positions in 3D Space...

1. Newbie
Join Date
Dec 2004
Posts
1

## Plotting Planetary Positions in 3D Space...

First of all I *really* suck at geometry, but want to create a little program that displays planets rotating around in dynamically generated star systems.

I need to plot a planets coordinates in 3D space at any given time based on a few factors...

Factors:
-OV: Planetary orbit velocity (how fast it moves around its star)

-OE: Orbital Eccentricity (how much its orbits is off the "Y" axis, ie up and down)
-HP: Direction of the "highest" point in its orbit

-FP: Direction of farthest point of its orbit
-AP: Distance of its farthest point of its orbit (aphelion)
-PE: Distance of its closest point of its orbit (perihelion)

-TIME: Time in seconds based on its initial position, to determine how far its moved

I'm sure this is all a pretty simple formula for somebody who understands objects moving around circles and ovals and such, but I can't find *anything* on the net or at Barns &amp; Nobels that is helping me

If you can't help but know a good place to point me I'd be very appreciative.

Thanks tons,

2. Ut
Established Member
Join Date
Feb 2004
Posts
2,494
OV
v^2 = GM/R, where v is the velocity of the planet, R is its distance away from its sun, and M is the mass of said sun. G is Newton's universal constant of gravity.

OE
Eccentricity characterizes how circular an orbit is. The word you're looking for is inclination. Most planets lie in an approximate plane.

HP
This depends on OE and AP.

sin(i) = h/R(max), where i is the inclination, h is the max height, and R(max) is AP.

FP, AP, PE
Look up the equation of an ellipse. Remember that the sun is located at one focus.

TIME
Err, shouldn't this take care of itself? v = v(R), and R = R(t).

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