IfcCartesianTransformationOperator2D

BACnet MVD

#### IfcCartesianTransformationOperator2D

Natural language names

| Kartesische Transformation - zweidimensional (2D)
| Cartesian Transformation Operator2 D
| Opérateur 2D de transformation cartésienne

Change log

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

##### 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 | B
--- | --- | --- | --- | --- | ---
| 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 | 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 | B
--- | --- | --- | --- | --- | ---
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

X

IfcGeometricRepresentationItem
IfcCartesianTransformationOperator
1 | Axis1 | IfcDirection | ? | The direction used to determine U[1], the derived X axis direction. | X | X
2 | Axis2 | IfcDirection | ? | The direction used to determine U[2], the derived Y axis direction. | X | 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 | X
4 | Scale | IfcReal | ? | The scaling value specified for the transformation. | X | 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 | X
| Dim :=LocalOrigin.Dim | IfcDimensionCount |  | The space dimensionality of this class, determined by the space dimensionality of the local origin. | X | 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 | 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

`

References: IfcSurfaceTexture IfcDerivedProfileDef IfcMirroredProfileDef

Link to this page