IFC 4.3.0.1 (IFC4X3_TC1)

8.9.3.17 IfcCartesianTransformationOperator3DnonUniform

8.9.3.17.1 Semantic definition

A Cartesian transformation operator 3d non uniform defines a geometric transformation in three-dimensional space composed of translation, rotation, mirroring and non uniform scaling. Non uniform scaling is given by three different scaling factors:

If the Scale factor (at supertype IfcCartesianTransformationOperator) is omitted, it defaults to 1.0. If the Scale2 or the Scale3 factor is omitted, it defaults to the value of Scale (the x axis scale factor).

8.9.3.17.2 Entity inheritance

8.9.3.17.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

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.

StyledByItem SET [0:1] OF IfcStyledItem FOR Item

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

IfcCartesianTransformationOperator (6)
1 Axis1 OPTIONAL IfcDirection

The direction used to determine U[1], the derived X axis direction.

2 Axis2 OPTIONAL IfcDirection

The direction used to determine U[2], the derived Y axis direction.

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.

4 Scale OPTIONAL IfcReal

The scaling value specified for the transformation.

* Scl IfcReal

This attribute is formally derived.

NVL(Scale, 1.0)

The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.

* Dim IfcDimensionCount

This attribute is formally derived.

LocalOrigin.Dim

The space dimensionality of this class, determined by the space dimensionality of the local origin.

IfcCartesianTransformationOperator3D (2)
5 Axis3 OPTIONAL IfcDirection

The exact direction of U[3], the derived Z axis direction.

* U LIST [3:3] OF IfcDirection

This attribute is formally derived.

IfcBaseAxis(3,SELF\IfcCartesianTransformationOperator.Axis1,
SELF\IfcCartesianTransformationOperator.Axis2,Axis3)

The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis3, Axis1, and Axis2 in that order.

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IfcCartesianTransformationOperator3DnonUniform (4)
6 Scale2 OPTIONAL IfcReal

The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.

7 Scale3 OPTIONAL IfcReal

The scaling value specified for the transformation along the axis 3. This is normally the z scale factor.

* Scl2 IfcReal

This attribute is formally derived.

NVL(Scale2, SELF\IfcCartesianTransformationOperator.Scl)

The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise.

* Scl3 IfcReal

This attribute is formally derived.

NVL(Scale3, SELF\IfcCartesianTransformationOperator.Scl)

The derived scale S(3) of the transformation along the axis 3 (normally the z axis), equal to Scale3 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise.

Table 8.9.3.17.A

8.9.3.17.4 Formal propositions

Name Description
Scale2GreaterZero

The derived scaling Scl2 shall be greater than zero.

Scl2 > 0.0
Scale3GreaterZero

The derived scaling Scl3 shall be greater than zero.

Scl3 > 0.0
Table 8.9.3.17.B

8.9.3.17.5 Formal representation

ENTITY IfcCartesianTransformationOperator3DnonUniform
 SUBTYPE OF (IfcCartesianTransformationOperator3D);
	Scale2 : OPTIONAL IfcReal;
	Scale3 : OPTIONAL IfcReal;
 DERIVE
	 Scl2 : IfcReal := NVL(Scale2, SELF\IfcCartesianTransformationOperator.Scl);
	 Scl3 : IfcReal := NVL(Scale3, SELF\IfcCartesianTransformationOperator.Scl);
 WHERE
	Scale2GreaterZero : Scl2 > 0.0;
	Scale3GreaterZero : Scl3 > 0.0;
END_ENTITY;

8.9.3.17.6 Changelog

8.9.3.17.6.1 IFC4

  • where rule, Scale2GreaterZero
  • where rule, Scale3GreaterZero
  • where rule, WR1
  • where rule, WR2
  • attribute Scale2 type, Changed from "real" to "IfcReal"
  • attribute Scale3 type, Changed from "real" to "IfcReal"