IFC 4.3.x development

8.15.3.12 IfcIShapeProfileDef

Change log

IFC4

additions attributes FlangeEdgeRadius
additions attributes FlangeSlope
additions where_rules ValidFilletRadius
additions where_rules ValidFlangeThickness
additions where_rules ValidWebThickness
deletions where_rules WR1
deletions where_rules WR2
deletions where_rules WR3
modificationsattributes FilletRadius definitionChanged from IfcPositiveLengthMeasure to IfcNonNegativeLengthMeasure

8.15.3.12.1 Semantic definitions at the entity

IfcIShapeProfileDef defines a section profile that provides the defining parameters of an 'I' or 'H' section. The I-shape profile has values for its overall depth, width and its web and flange thicknesses. Additionally a fillet radius, flange edge radius, and flange slope may be given. This profile definition represents an I-section which is symmetrical about its major and minor axes; top and bottom flanges are equal and centred on the web.

HISTORY  New entity in IFC2x.

IFC4 CHANGE  Type of FilletRadius relaxed to allow for zero radius. Attributes FlangeEdgeRadius and FlangeSlope added.

Figure 1 illustrates parameters of the I-shape profile definition.

I-shape profile

Position
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. Explicit coordinate offsets are used to define cardinal points (e.g. upper-left bound).

Parameter
The parameterized profile is defined by a set of parameter attributes, see attribute definition below.

I shape with fillet
Note: The black coordinate axes show the underlying coordinate system of the swept surface or swept area solid

Position
The profile is inserted into the underlying coordinate system of the swept area solid by using the Position attribute. In this example (cardinal point of lower left corner) the attribute values of IfcAxis2Placement2D are:

Location = IfcCartesianPoint(<1/2 OverallWidth>,<1/2 OverallDepth>)
RefDirection = NIL (defaults to 1.,0.)

Parameter
If the FilletRadius is given, it is equally applied to all four corners created by the web and flanges.

Figure 1 — I-shape profile

8.15.3.12.1 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.
IfcIShapeProfileDef
4 OverallWidth IfcPositiveLengthMeasure Total extent of the width, defined parallel to the x axis of the position coordinate system.
5 OverallDepth IfcPositiveLengthMeasure Total extent of the depth, defined parallel to the y axis of the position coordinate system.
6 WebThickness IfcPositiveLengthMeasure Thickness of the web of the I-shape. The web is centred on the x-axis and the y-axis of the position coordinate system.
7 FlangeThickness IfcPositiveLengthMeasure Flange thickness of the I-shape. Both, the upper and the lower flanges have the same thickness and they are centred on the y-axis of the position coordinate system.
8 FilletRadius OPTIONAL IfcNonNegativeLengthMeasure The fillet between the web and the flange. 0 if sharp-edged, omitted if unknown.
9 FlangeEdgeRadius OPTIONAL IfcNonNegativeLengthMeasure Radius of the lower edges of the top flange and the upper edges of the bottom flange. 0 if sharp-edged, omitted if unknown.
10 FlangeSlope OPTIONAL IfcPlaneAngleMeasure Slope of the lower faces of the top flange and of the upper faces of the bottom flange. Non-zero in case of tapered flanges, 0 in case of parallel flanges, omitted if unknown.

8.15.3.12.2 Entity inheritance

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

8.15.3.12.3 Definitions applying to General Usage

8.15.3.12.3.1 Property Sets for Objects

PsetName
'Pset_ProfileMechanical'

8.15.3.12.4 Formal representations

ENTITY IfcIShapeProfileDef
 SUBTYPE OF (IfcParameterizedProfileDef);
	OverallWidth : IfcPositiveLengthMeasure;
	OverallDepth : IfcPositiveLengthMeasure;
	WebThickness : IfcPositiveLengthMeasure;
	FlangeThickness : IfcPositiveLengthMeasure;
	FilletRadius : OPTIONAL IfcNonNegativeLengthMeasure;
	FlangeEdgeRadius : OPTIONAL IfcNonNegativeLengthMeasure;
	FlangeSlope : OPTIONAL IfcPlaneAngleMeasure;
 WHERE
	ValidFlangeThickness : (2. * FlangeThickness) < OverallDepth;
	ValidWebThickness : WebThickness < OverallWidth;
	ValidFilletRadius : NOT(EXISTS(FilletRadius)) OR
((FilletRadius <= (OverallWidth - WebThickness)/2.) AND 
 (FilletRadius <= (OverallDepth - (2. * FlangeThickness))/2.));
END_ENTITY;