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?
uh,
more info please.
with an angle in 2d all you have is an angle.
with an angle and a point you have a line.
trying to find a point on a sphere a specific radius away. my 2d example: cos(angle)=x, sin(angle)=y, on a unit circle(circle with radius of 1). Is there something relevant to this in spheres? i assume, however, that you need 2 angles instead of one to find the x, y, and z. am i right?
Yes, you can use two angles to define a point on a sphere. Elevation/azimuth, or longitude/latitude, whatever you want to call them.
If theta is the angle from the North pole (90-latitude) and phi is the longitude, then
x = sin(phi) * sin(theta)
y = cos(phi) * sin(theta)
z = cos(theta)
To fully define an orientation you’ll need a third angle which is a rotation about this vector. Look up the term “Euler angles” in Google for more details.