IfcIShapeProfileDef

Semantic definitions at the entity

Entity definition

Definition from IAI: The IfcIShapeProfileDef defines a section profile that provides the defining parameters of a symmetrical 'I' section to be used by the swept surface geometry or the swept area solid. The I-shape profile has values for its overall depth, width and its web and flange thickness. Additionally a fillet radius may be given. It represents a I-section that is symmetrical about its major and minor axes; and that has both top and bottom flanges being equal and centred on the web.

HISTORY: New entity in IFC Release 2x.

Illustration:

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:

IfcSweptAreaSolid.Position

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.

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.

Table: Parameter of the I-shape profile definition

Attribute definitions

#	Attribute	Type	Cardinality	Description	A
4	OverallWidth	IfcPositiveLengthMeasure	[1:1]	Total extent of the width, defined parallel to the x axis of the position coordinate system.	X
5	OverallDepth	IfcPositiveLengthMeasure	[1:1]	Total extent of the depth, defined parallel to the y axis of the position coordinate system.	X
6	WebThickness	IfcPositiveLengthMeasure	[1:1]	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.	X
7	FlangeThickness	IfcPositiveLengthMeasure	[1:1]	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.	X
8	FilletRadius	-		This attribute is out of scope for this model view definition and shall not be set.

Formal Propositions

Rule	Description
WR1	The thickness of the flange shall be less than half of the overall depth.
WR2	The web thickness shall be less then the overall width.
WR3	The FilletRadius, if given, should be within the range of allowed values.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcProfileDef
1	ProfileType	IfcProfileTypeEnum	[1:1]	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.	X
2	ProfileName	-		This attribute is out of scope for this model view definition and shall not be set.
IfcParameterizedProfileDef
3	Position	IfcAxis2Placement2D	[1:1]	Position coordinate system of the parameterized profile definition.	X
IfcIShapeProfileDef
4	OverallWidth	IfcPositiveLengthMeasure	[1:1]	Total extent of the width, defined parallel to the x axis of the position coordinate system.	X
5	OverallDepth	IfcPositiveLengthMeasure	[1:1]	Total extent of the depth, defined parallel to the y axis of the position coordinate system.	X
6	WebThickness	IfcPositiveLengthMeasure	[1:1]	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.	X
7	FlangeThickness	IfcPositiveLengthMeasure	[1:1]	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.	X
8	FilletRadius	-		This attribute is out of scope for this model view definition and shall not be set.

Formal representations

XSD Specification

 <xs:element name="IfcIShapeProfileDef" type="ifc:IfcIShapeProfileDef" substitutionGroup="ifc:IfcParameterizedProfileDef" nillable="true"/>

 <xs:complexType name="IfcIShapeProfileDef">

  <xs:complexContent>

   <xs:extension base="ifc:IfcParameterizedProfileDef">

    <xs:attribute name="OverallWidth" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

    <xs:attribute name="OverallDepth" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

    <xs:attribute name="WebThickness" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

    <xs:attribute name="FlangeThickness" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcIShapeProfileDef

 SUPERTYPE OF(IfcAsymmetricIShapeProfileDef)

 SUBTYPE OF (IfcParameterizedProfileDef);

  OverallWidth : IfcPositiveLengthMeasure;

  OverallDepth : IfcPositiveLengthMeasure;

  WebThickness : IfcPositiveLengthMeasure;

  FlangeThickness : IfcPositiveLengthMeasure;

  FilletRadius : OPTIONAL IfcStrippedOptional;

 WHERE

  WR1 : FlangeThickness < (OverallDepth / 2.);
  WR2 : WebThickness < OverallWidth;
  WR3 : NOT(EXISTS(FilletRadius)) OR
((FilletRadius <= (OverallWidth - WebThickness)/2.) AND 
 (FilletRadius <= (OverallDepth - (2. * FlangeThickness))/2.));
END_ENTITY;

 EXPRESS-G diagram