# Coordinate system: definition (structure)

## Definition

A coordinate system is defined by:

• a name (and a comment)
• a type of coordinate system
• a reference coordinate system (or parent coordinate system)
• the positioning of the coordinate system in the reference coordinate system

## Name

The name to identify the coordinate system is set by the user during the creation of this one.

A comment (optional) can be added to the name.

## Types of coordinate systems

The types of coordinate systems and the characteristics useful for their description are presented in the table below.

Type of coordinate system Coordinates
Cartesian (x,y,z)
Cylindrical (r,θ,z)
Spherical (r,θ,φ)

## Reference coordinate system

A coordinate system is defined with respect to a reference coordinate system (or parent coordinate system). The different reference coordinate systems are presented in the table below.

Coordinate system Description
defined with respect to the global coordinate system length unit (m, mm, µm, inch or user's unit) angle unit (degree, radian or user's unit)
defined with respect to a local coordinate system name of parent coordinate system

## Positioning

A coordinate system is positioned in its reference coordinate system using:

• the center coordinates of this coordinate system expressed in the reference coordinate system
• rotation angles of the axes of this coordinate system with respect to the axes of the reference coordinate system
Origin of coordinate system Rotation angle
• first component
• second component
• third component