IfcAxis2Placement2D

Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: 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.

If the RefDirection attribute is not given, the placement defaults to P[1] (x-axis) as [1.,0.] and P[2] (y-axis) as [0.,1.].

NOTE: Corresponding STEP name: axis2_placement_2d, please refer to ISO/IS 10303-42:1994, 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 two-dimensional coordinate system.

Attribute definitions

#	Attribute	Type	Cardinality	Description	A
2	RefDirection	-		This attribute is out of scope for this model view definition and shall not be set.
	P :=IfcBuild2Axes(RefDirection)	IfcDirection	L[2:2]	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].	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcRepresentationItem
IfcGeometricRepresentationItem
IfcPlacement
1	Location	IfcCartesianPoint	[1:1]	The geometric position of a reference point, such as the center of a circle, of the item to be located.	X
	Dim :=Location.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, derived from the dimensionality of the location.	X
IfcAxis2Placement2D
2	RefDirection	-		This attribute is out of scope for this model view definition and shall not be set.
	P :=IfcBuild2Axes(RefDirection)	IfcDirection	L[2:2]	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].	X

Formal representations

XSD Specification

 <xs:element name="IfcAxis2Placement2D" type="ifc:IfcAxis2Placement2D" substitutionGroup="ifc:IfcPlacement" nillable="true"/>

 <xs:complexType name="IfcAxis2Placement2D">

  <xs:complexContent>

   <xs:extension base="ifc:IfcPlacement"/>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcAxis2Placement2D

 SUBTYPE OF (IfcPlacement);

  RefDirection : OPTIONAL IfcStrippedOptional;

 DERIVE

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

 WHERE

  WR1 : (NOT (EXISTS (RefDirection))) OR (RefDirection.Dim = 2);
  WR2 : SELF\IfcPlacement.Location.Dim = 2;
END_ENTITY;

 EXPRESS-G diagram