IfcCartesianTransformationOperator2D

Semantic definitions at the entity

Entity definition

An IfcCartesianTransformationOperator2D defines a geometric transformation in two-dimensional space.

NOTE Definition according to 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 Entity adapted from cartesian_transformation_operator_2d defined in ISO10303-42.

HISTORY New entity in IFC2x.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
	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
DimEqual2	The coordinate space dimensionality of this entity shall be 2.
Axis1Is2D	The inherited Axis1 should have (if given) the dimensionality of 2.
Axis2Is2D	The inherited Axis2 should have (if given) the dimensionality of 2.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. IFC2x3 CHANGE The inverse attribute LayerAssignments has been added. IFC4 CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. IFC2x3 CHANGE The inverse attribute StyledByItem has been added.	X
IfcGeometricRepresentationItem
IfcCartesianTransformationOperator
1	Axis1	IfcDirection	?	The direction used to determine U[1], the derived X axis direction.	X
2	Axis2	IfcDirection	?	The direction used to determine U[2], the derived Y axis direction.	X
3	LocalOrigin	IfcCartesianPoint		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	IfcReal	?	The scaling value specified for the transformation.	X
	Scl :=NVL(Scale, 1.0)	IfcReal		The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.	X
	Dim :=LocalOrigin.Dim	IfcDimensionCount		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

XML 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

 SUPERTYPE OF(IfcCartesianTransformationOperator2DnonUniform)

 SUBTYPE OF (IfcCartesianTransformationOperator);

 DERIVE

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

 WHERE

  DimEqual2 : SELF\IfcCartesianTransformationOperator.Dim = 2;
  Axis1Is2D : NOT(EXISTS(SELF\IfcCartesianTransformationOperator.Axis1)) OR 

(SELF\IfcCartesianTransformationOperator.Axis1.Dim = 2);
  Axis2Is2D : NOT(EXISTS(SELF\IfcCartesianTransformationOperator.Axis2)) OR 

(SELF\IfcCartesianTransformationOperator.Axis2.Dim = 2);
END_ENTITY;

 EXPRESS-G diagram

	Kartesische Transformation - zweidimensional (2D)
	Cartesian Transformation Operator 2D
	Opérateur 2D de transformation cartésienne

Item	Change	Description
IFC4 Addendum 1
IfcCartesianTransformationOperator2D
Scale	MODIFIED	Type changed from REAL to IfcReal.