IfcAxis2Placement2D
Definition from ISO/CD 1030342:1992: The location and
orientation in two dimensional space of two mutually perpendicular axes. An
axis2_placement_2d is defined in terms of a point, (inherited from the
placement supertype), and an axis. It can be used to locate and originate an
object in two dimensional space and to define a placement coordinate system.
The class includes a point which forms the origin of the placement coordinate
system. A direction vector is required to complete the definition of the
placement coordinate system. The reference direction defines the placement X
axis direction, the placement Y axis is derived from this.
Definition from buildingSMART: If the RefDirection attribute is not
given, the placement defaults to P[1] (xaxis) as [1.,0.] and P[2] (yaxis) as
[0.,1.].
NOTE: Corresponding STEP name:
axis2_placement_2d, please refer to ISO/IS 1030342:1994, p. 28 for the final
definition of the formal standard.
HISTORY: New entity in IFC Release
1.5.
Illustration

Definition of the
IfcAxis2Placement2D within the twodimensional coordinate
system. 
EXPRESS specification:



P

:

LIST [2:2] OF IfcDirection := IfcBuild2Axes(RefDirection);



WR1

:

(NOT (EXISTS (RefDirection))) OR (RefDirection.Dim = 2);

WR2

:

SELF\IfcPlacement.Location.Dim = 2;




Attribute definitions:
RefDirection

:

The direction used to determine the direction of the local X Axis.

P

:

P[1]: The normalized direction of the placement X Axis. This is (1.0,0.0,0.0) if RefDirection is omitted.
P[2]: The normalized direction of the placement Y Axis. This is a derived attribute and is orthogonal
to P[1].

Inheritance graph

ENTITY IfcAxis2Placement2D;



P

:

LIST [2:2] OF IfcDirection := IfcBuild2Axes(RefDirection);



