IFC 4.3.x development

8.15.3.5 IfcCShapeProfileDef

Change log

IFC4

additions where_rules ValidGirth
additions where_rules ValidInternalFilletRadius
additions where_rules ValidWallThickness
deletions attributes CentreOfGravityInX
deletions where_rules WR1
deletions where_rules WR2
deletions where_rules WR3
modificationsattributes InternalFilletRadius definitionChanged from IfcPositiveLengthMeasure to IfcNonNegativeLengthMeasure

8.15.3.5.1 Semantic definitions at the entity

IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profile's centre of the bounding box.

HISTORY  New entity in IFC2x2.

IFC2x3 CHANGE  All profile origins are now in the center of the bounding box.

IFC4 CHANGE  Type of InternalFilletRadius relaxed to allow for zero radius. Trailing attribute CentreOfGravityInX deleted, use respective property in IfcExtendedProfileProperties instead.

Figure 1 illustrates parameters of the C-shape profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of:

By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. The parameterized profile is defined by a set of parameter attributes. In the illustrated example, the 'CentreOfGravityInX' property in IfcExtendedProfileProperties, if provided, is negative.

"C-shape profile"

8.15.3.5.1 Attributes

# Attribute Type Description
IfcProfileDef
1 ProfileType IfcProfileTypeEnum 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.
2 ProfileName OPTIONAL IfcLabel 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_.
HasExternalReferenceSET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjectsReference to external information, e.g. library, classification, or document information, which is associated with the profile.

> IFC4 CHANGE New inverse attribute
HasProperties SET [0:?] OF IfcProfileProperties FOR ProfileDefinition Additional properties of the profile, for example mechanical properties.

> IFC4 CHANGE New inverse attribute
IfcParameterizedProfileDef
3 Position OPTIONAL IfcAxis2Placement2D Position coordinate system of the parameterized profile definition. If unspecified, no translation and no rotation is applied.
IfcCShapeProfileDef
4 Depth IfcPositiveLengthMeasure Profile depth, see illustration above (= h).
5 Width IfcPositiveLengthMeasure Profile width, see illustration above (= b).
6 WallThickness IfcPositiveLengthMeasure Constant wall thickness of profile (= ts).
7 Girth IfcPositiveLengthMeasure Lengths of girth, see illustration above (= c).
8 InternalFilletRadiusOPTIONAL IfcNonNegativeLengthMeasure Internal fillet radius according the above illustration (= r1).

8.15.3.5.2 Entity inheritance

dot_inheritance IfcCShapeProfileDef IfcCShapeProfileDef IfcParameterizedProfileDef IfcParameterizedProfileDef IfcCShapeProfileDef->IfcParameterizedProfileDef IfcParameterizedProfileDef_children 10 more... IfcParameterizedProfileDef_children->IfcParameterizedProfileDef IfcProfileDef IfcProfileDef IfcParameterizedProfileDef->IfcProfileDef IfcProfileDef_children 5 more... IfcProfileDef_children->IfcProfileDef

8.15.3.5.3 Definitions applying to General Usage

8.15.3.5.3.1 Property Sets for Objects

PsetName
'Pset_ProfileMechanical'

8.15.3.5.4 Formal representations

ENTITY IfcCShapeProfileDef
 SUBTYPE OF (IfcParameterizedProfileDef);
	Depth : IfcPositiveLengthMeasure;
	Width : IfcPositiveLengthMeasure;
	WallThickness : IfcPositiveLengthMeasure;
	Girth : IfcPositiveLengthMeasure;
	InternalFilletRadius : OPTIONAL IfcNonNegativeLengthMeasure;
 WHERE
	ValidGirth : Girth < (Depth / 2.);
	ValidInternalFilletRadius : NOT(EXISTS(InternalFilletRadius)) OR
((InternalFilletRadius <= Width/2. - WallThickness) AND (InternalFilletRadius <= Depth/2. - WallThickness));
	ValidWallThickness : (WallThickness < Width/2.) AND (WallThickness < Depth/2.);
END_ENTITY;