Struggling artist here, please excuse my very basic understanding / lack of technical terms. I've included a quick diagram to make it easier to explain my question.
Is it possible, assuming distance "a" is known, to determine what distance "b" will be? I'm trying to better understand how far apart 90 degree slices are when rotating a spherical object, but obviously the distance changes depending on where the two points are on the rotating axis relative to the viewpoint. Does that make sense?
(also, in the diagram,, by "b" i mean distance on the centre line).