IFC 4.3.x development

8.9.3.17 IfcCartesianTransformationOperator3DnonUniform

Change log

IFC4

additions where_rules Scale2GreaterZero
additions where_rules Scale3GreaterZero
deletions where_rules WR1
deletions where_rules WR2
modificationsattributes Scale2 definitionChanged from real to IfcReal
modificationsattributes Scale3 definitionChanged from real to IfcReal

8.9.3.17.1 Semantic definitions at the entity

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).

NOTE  The scale factor (Scl) defined at the supertype IfcCartesianTransformationOperator is used to express the calculated Scale factor (normally x axis scale factor).

HISTORY  New entity in IFC2x.

8.9.3.17.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
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.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcCartesianTransformationOperator
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 INVALID The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.
Dim INVALID The space dimensionality of this class, determined by the space dimensionality of the local origin.
IfcCartesianTransformationOperator3D
5 Axis3 OPTIONAL IfcDirection The exact direction of U[3], the derived Z axis direction.
U INVALID 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.
IfcCartesianTransformationOperator3DnonUniform
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 INVALID 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 INVALID 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.

8.9.3.17.2 Entity inheritance

dot_inheritance IfcCartesianTransformationOperator3DnonUniform IfcCartesianTransformationOperator3DnonUniform IfcCartesianTransformationOperator3D IfcCartesianTransformationOperator3D IfcCartesianTransformationOperator3DnonUniform->IfcCartesianTransformationOperator3D IfcCartesianTransformationOperator IfcCartesianTransformationOperator IfcCartesianTransformationOperator3D->IfcCartesianTransformationOperator IfcCartesianTransformationOperator2D IfcCartesianTransformationOperator2D IfcCartesianTransformationOperator2D->IfcCartesianTransformationOperator IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcCartesianTransformationOperator->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.17.3 Formal representations

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;