IfcDerivedProfileDef defines the profile by transformation from the parent profile. The transformation is given by a two dimensional transformation operator. Transformation includes translation, rotation, mirror and scaling. The latter can be uniform or non uniform. The derived profiles may be used to define swept surfaces, swept area solids or sectioned spines.
The transformation effects the position, rotation, mirroring or scale of the profile at the underlying coordinate system, i.e. the coordinate system defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either:
or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions. The position and potential rotation of the ParentProfile within the underlying coordinate system is taken into consideration before applying the Cartesian transformation operator.
Note, if only mirroring is required, IfcMirroredProfileDef should be used instead.
The example shows an uniform scaling and a transformation of an IfcRectangleProfileDef to match the lower-left cardinal point. The attributes of the CTO are:
Axis1 = NIL (defaults to 1.,0.) Axis2 = NIL (defaults to 0.,1.) LocalOrigin = IfcCartesianPoint(<1/2 XDim>,<1/2 YDim>) Scale = 2.
The example shows a non-uniform scaling and a translation of an IfcRectangleProfileDef to match the lower-left cardinal point. The attributes of the CTO are:
Axis1 = NIL (defaults to 1.,0.) Axis2 = NIL (defaults to 0.,1.) LocalOrigin = IfcCartesianPoint(0.,<1/2 YDim>) Scale = 1. Scale2 = 2.
The example shows a mirroring of an IfcLShapeProfileDef to match the centre cardinal point. The attributes of the CTO are:
Axis1 = (-1.,0.) Axis2 = NIL (defaults to 0.,1.) LocalOrigin = IfcCartesianPoint(0.,0.) Scale = NIL (defaults to 1.)
Note: The following color map applies:
- black coordinate axes show the underlying coordinate system of the swept surface, swept area solid, or sectioned spine
- red coordinate axes show the position coordinate system of the parent profile
- brown coordinate axes show the position coordinate system of the derived profile
Defines the type of geometry into which this profile definition shall be resolved, either a curve or a surface area. In case of curve the profile should be referenced by a swept surface, in case of area the profile should be referenced by a swept area solid.
Human-readable name of the profile, for example according to a standard profile table. As noted above, machine-readable standardized profile designations should be provided in IfcExternalReference.ItemReference.
|HasExternalReference||SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects||
Reference to external information, e.g. library, classification, or document information, which is associated with the profile.
|HasProperties||SET [0:?] OF IfcProfileProperties FOR ProfileDefinition||
Additional properties of the profile, for example mechanical properties.
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The parent profile provides the origin of the transformation.
Transformation operator applied to the parent profile.
The name by which the transformation may be referred to. The actual meaning of the name has to be defined in the context of applications.
The profile type of the derived profile shall be the same as the type of the parent profile, i.e. both shall be either AREA or CURVE.
|Property Sets for Profiles||General||
This concept can be applied to the following resources:
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ENTITY IfcDerivedProfileDef SUPERTYPE OF (ONEOF (IfcMirroredProfileDef)) SUBTYPE OF (IfcProfileDef); ParentProfile : IfcProfileDef; Operator : IfcCartesianTransformationOperator2D; Label : OPTIONAL IfcLabel; WHERE InvariantProfileType : SELF\IfcProfileDef.ProfileType = ParentProfile.ProfileType; END_ENTITY;