[Member 4148]

Originally posted by Imperator Fyron:
y position is not height.

can be - it depends on coordinate system used
there is no particular reason why the center of the sphere has to be the 0 point - he wanted the answer from the bottom of the sphere after all
likewise there is no particular reason why z has to be up, y back, and x right - reducing to circle makes y up using cartesian so it works as height

Originally posted by Imperator Fyron:
Not sure what I was thinking with arc length, but you definitely need the angles associated with the vector from the starting point to the ending point. The relative height is just the z component of that vector.

Treating the movement as along a circle only works if the only component that is changing is the z component. If x or y change (but not both), then it is no longer a circle, but an ellipse.

you forgetting - he constraining himself to move on surface of sphere - any 'straight line' path constrained so makes for a segment of a perfect circle from some perspective - if you choose that perspective, it reduces to a circle just fine
also, narf specified direction of travel - to the right - which pretty much forces a circle sgement anyway