Angular co-ordinates are defined by specifying:
The distance along a chosen rotary axis
The distance along one other axis
An absolute angle of rotation around the rotary axis.
The rotary axes A, B, C correspond to X, Y and Z respectively, with the positive direction of rotation being clockwise:
The example below shows a point positioned by distance ‘a’ along the A axis, distance ‘b’ along the B axis and an angle ‘q’ with respect to the A axis:
