G.4.1 Global Coordinate System
The following coordinate systems are available for specification of the structure geometry.
 Conventional Cartesian Coordinate System

This coordinate system is a rectangular coordinate system (X, Y, Z) which follows the orthogonal right hand rule. This coordinate system may be used to define the joint locations and loading directions.
 Cylindrical Coordinate System

In this coordinate system, the X and Y coordinates of the conventional Cartesian system are replaced by R (radius) and Ø (angle in degrees). The Z coordinate is identical to the Z coordinate of the Cartesian system and its positive direction is determined by the right hand rule.
 Reverse Cylindrical Coordinate System

This is a cylindrical type coordinate system where the R Ø plane corresponds to the XZ plane of the Cartesian system. The right hand rule is followed to determine the positive direction of the Y axis.