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dutchstud
02-15-2002, 08:32 AM
in 2 dimensions, it is possible to find point x,y using just one angle. Is there some way of doing this in 3d? i would guess you need 2 angles, one off the horizon, and one for z, but i'm not sure. anyone know?

Bob
02-15-2002, 11:47 AM
Nope, not possible. Using an angle only (in 2D), you get a line. Same in 3D, using two angles you get a line.

To represent a unique point on that line, you need a distance from a reference point, or something similar to identify it among the other points on the line (which is an infinite amount of points).

nexusone
02-15-2002, 12:38 PM
I think you are trying to find a point on a sphere.

To find a point on a circle in 2D space:

x = radius * cos( angle in radins )
y = radius * sin( angle in radins )

To find a point on a sphere in 3D space takes a little more work so here is a link to a page on 3D math.
http://www.geocities.com/SiliconValley/2151/math3d.html



Originally posted by dutchstud:
in 2 dimensions, it is possible to find point x,y using just one angle. Is there some way of doing this in 3d? i would guess you need 2 angles, one off the horizon, and one for z, but i'm not sure. anyone know?

dutchstud
02-15-2002, 02:43 PM
yeah, that's what i meant, with a certain radius, to find a point on a sphere. thanks.