| | Describes a right-handed coordinate system in 3D space.
A coordinate system is defined by:
- its origin, also termed the "Location point" of the coordinate system,
- three orthogonal unit vectors, termed respectively
the "X Direction", "Y Direction" and "Direction" (or
"main Direction") of the coordinate system.
As a Geom_Axis2Placement coordinate system is
right-handed, its "Direction" is always equal to the
cross product of its "X Direction" and "Y Direction".
The "Direction" of a coordinate system is called the
"main Direction" because when this unit vector is
modified, the "X Direction" and "Y Direction" are
recomputed, whereas when the "X Direction" or "Y <br>
Direction" is changed, the "main Direction" is
retained. The "main Direction" is also the "Z Direction".
Note: Geom_Axis2Placement coordinate systems
provide the same kind of "geometric" services as
gp_Ax2 coordinate systems but have more complex
data structures. The geometric objects provided by
the Geom package use gp_Ax2 objects to include
coordinate systems in their data structures, or to
define the geometric transformations, which are applied to them.
Geom_Axis2Placement coordinate systems are
used in a context where they can be shared by
several objects contained inside a common data structure.
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1.6.3