ABSTRACT
The World Coordinate System (WCS) All readers should be familiar with the basic 2D coordinate concept of a point described as P1 (30,40) – Fig. 3.1. Such a point has 30 units in the positive X-direction and 40 units in the positive Y-direction. These ordinates are relative to an XY axes system with the origin at the point (0,0). This origin is normally positioned at the lower left corner of the screen and is perfectly satisfactory for 2D draughting but not for 3D modelling.
