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IfcProfileDef

Definition from IAI: The IfcProfileDef is the supertype of all definitions of standard and arbitrary profiles within IFC. It is used to define a standard set of commonly used profiles by their parameters. Those profile definitions are used within the geometry and geometric model resource to create either swept surfaces or swept area solids. The purpose of the profile definition within the swept surfaces or swept area solids is to define a cross section. Profiles are also used within sectioned spines, where the consecutive profiles can be based on transformations of the start profile given by derived profiles.

Standard profiles are 2D primitives, which are used within the industry to describe cross sections by a description of its parameters. Arbitrary profiles are cross sections defined by an outer boundary as bounded curve, which may also include holes, defined by inner bounderies. Derived profiles, based on a transformation of a parent profile, are also part of the profile definitions available. In addition composite profiles can be defined, which include two or more profile definitions to define the resulting profile.

An IfcProfileDef is treated as bounded area if it is used within swept area solids. In this case, the inside of the profile is part of the profile. The attribute ProfileType is set to AREA. An IfcProfileDef is treated as a curve if it is used within swept surfaces. In this case, the inside of the profile (if the curve is closed) is not part of the profile. The attribute ProfileType is set to CURVE. The optional attribute ProfileName can be used to designate a standard profile type as e.g. given in profile tables for steel profiles.

HISTORY: New class in IFC Release 1.5, the capabilities have been extended in IFC Release 2x. Profiles can now support swept surfaces and swept area solids with inner boundaries. It had been renamed from IfcAttDrivenProfileDef.
ISSUE: See issue log for changes made in IFC Release 1.5, and see issue and change log for changes made in IFC Release 2x.

Illustration:

Example of standard profile definition Position
The IfcProfileDef is defined within a 2D coordinate system. The standard profile definitions define a 2D position coordinate system, relative to the underlying 2D coordinate system of the IfcProfileDef.
Table: abstract supertype for profile definitions

Geometry use case:

use within swept area solids In the later use of the IfcProfileDef within the 
  • IfcExtrudedAreaSolid (used as example) or the 
  • IfcRevolvedAreaSolid
the underlying coordinate system of the resulting boundaries (2D coordinate system of IfcProfileDef) is placed within the xy plane of the 3D position coordinate system of the swept area solid. The placement is at (0.,0.) and the directions are (1.,0.) and (0.,1.).
Table: Use of IfcProfileDef within the swept area solids

Use cases:

Results of the different usage of the ProfileType attribute. The ProfileType defines whether the inside (the bounded area) is part of the profile definition (Area) or not (Curve).
area without thickness ProfileType = AREA
closed curve ProfileType = CURVE
Table: Resulting area or curve depending on ProfileType

EXPRESS specification:

ENTITY IfcProfileDef
ABSTRACT SUPERTYPE OF (ONEOF(IfcArbitraryClosedProfileDef, IfcCircleProfileDef, IfcRectangleProfileDef, IfcTrapeziumProfileDef, IfcEllipseProfileDef, IfcRoundedRectangleProfileDef, IfcDerivedProfileDef, IfcArbitraryOpenProfileDef, IfcIshapeProfileDef, IfcCompositeProfileDef));
ProfileType  :  IfcProfileTypeEnum;
ProfileName  :  OPTIONAL IfcLabel;
END_ENTITY;

Attribute definitions:

ProfileType  :  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.
ProfileName  :  Name of the profile type according to some standard profile table.

References (12):

Name Type Referred through Express-G
IfcArbitraryClosedProfileDef Entity
Supertype
Diagram 3
IfcArbitraryOpenProfileDef Entity
Supertype
Diagram 3
IfcCircleProfileDef Entity
Supertype
Diagram 1
IfcCompositeProfileDef Entity
Supertype
Attribute 'Profiles'
Diagram 3
IfcDerivedProfileDef Entity
Supertype
Attribute 'ParentProfile'
Diagram 3
IfcEllipseProfileDef Entity
Supertype
Diagram 1
IfcIshapeProfileDef Entity
Supertype
Diagram 2
IfcRectangleProfileDef Entity
Supertype
Diagram 1
IfcRoundedRectangleProfileDef Entity
Supertype
Diagram 2
IfcTrapeziumProfileDef Entity
Supertype
Diagram 2

Inheritance graph

ENTITY IfcProfileDef;
ENTITY IfcProfileDef;
ProfileType  :  IfcProfileTypeEnum;
ProfileName  :  OPTIONAL IfcLabel;
END_ENTITY;