IfcCartesianTransformationOperator2D

Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: A Cartesian transformation operator 2d defines a geometric transformation in two-dimensional space composed of translation, rotation, mirroring and uniform scaling. The list of normalized vectors u defines the columns of an orthogonal matrix T. These vectors are computed from the direction attributes axis1 and axis2 by the base axis function. If |T|= -1, the transformation includes mirroring.

NOTE: Corresponding STEP entity : cartesian_transformation_operator_2d, please refer to ISO/IS 10303-42:1994, p. 36 for the final definition of the formal standard.

HISTORY: New entity in IFC Release 2x.

Attribute definitions

#	Attribute	Type	Cardinality	Description	A
	U :=IfcBaseAxis(2,SELF\IfcCartesianTransformationOperator.Axis1, SELF\IfcCartesianTransformationOperator.Axis2,?)	IfcDirection	L[2:2]	The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis1 and Axis2 in that order.	X

Formal Propositions

Rule	Description
WR1	The coordinate space dimensionality of this entity shall be 2.
WR2	The inherited Axis1 should have (if given) the dimensionality of 2.
WR3	The inherited Axis2 should have (if given) the dimensionality of 2.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcRepresentationItem
IfcGeometricRepresentationItem
IfcCartesianTransformationOperator
1	Axis1	-		This attribute is out of scope for this model view definition and shall not be set.
2	Axis2	-		This attribute is out of scope for this model view definition and shall not be set.
3	LocalOrigin	IfcCartesianPoint	[1:1]	The required translation, specified as a cartesian point. The actual translation included in the transformation is from the geometric origin to the local origin.	X
4	Scale	-		This attribute is out of scope for this model view definition and shall not be set.
	Scl :=NVL(Scale, 1.0)	REAL	[1:1]	The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.	X
	Dim :=LocalOrigin.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, determined by the space dimensionality of the local origin.	X
IfcCartesianTransformationOperator2D
	U :=IfcBaseAxis(2,SELF\IfcCartesianTransformationOperator.Axis1, SELF\IfcCartesianTransformationOperator.Axis2,?)	IfcDirection	L[2:2]	The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis1 and Axis2 in that order.	X

Formal representations

XSD Specification

 <xs:element name="IfcCartesianTransformationOperator2D" type="ifc:IfcCartesianTransformationOperator2D" substitutionGroup="ifc:IfcCartesianTransformationOperator" nillable="true"/>

 <xs:complexType name="IfcCartesianTransformationOperator2D">

  <xs:complexContent>

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

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCartesianTransformationOperator2D

 SUBTYPE OF (IfcCartesianTransformationOperator);

 DERIVE

  U : LIST [2:2] OF IfcDirection := IfcBaseAxis(2,SELF\IfcCartesianTransformationOperator.Axis1,
SELF\IfcCartesianTransformationOperator.Axis2,?);

 WHERE

  WR1 : SELF\IfcCartesianTransformationOperator.Dim = 2;
  WR2 : NOT(EXISTS(SELF\IfcCartesianTransformationOperator.Axis1)) OR 
(SELF\IfcCartesianTransformationOperator.Axis1.Dim = 2);
  WR3 : NOT(EXISTS(SELF\IfcCartesianTransformationOperator.Axis2)) OR 
(SELF\IfcCartesianTransformationOperator.Axis2.Dim = 2);
END_ENTITY;

 EXPRESS-G diagram