IfcTrapeziumProfileDef

Semantic definitions at the entity

Entity definition

IfcTrapeziumProfileDef defines a trapezium as the profile definition used by the swept surface geometry or the swept area solid. It is given by its Top X and Bottom X extent and its Y extent as well as by the offset of the Top X extend, and placed within the 2D position coordinate system, established by the Position attribute. It is placed centric within the position coordinate system, that is, in the center of the bounding box.

HISTORY New entity in IFC1.5. The use definition has changed in IFC2x.

Figure 429 illustrates parameters of the trapezium profile definition.

Position
The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept surface or swept area solid that uses the profile definition. It is the xy plane of either:

IfcSweptSurface.Position
IfcSweptAreaSolid.Position

or in case of sectioned spines the xy plane of each list member of IfcSectionedSpine.CrossSectionPositions.

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 IfcTrapeziumProfileDef is defined within the position coordinate system, where the BottomDim defines the length measure for the bottom line (half along the positive x-axis) and the YDim defines the length measure for the parallel distance of bottom and top line (half along the positive y-axis). The top line starts with a distance of TopXOffset from [-BottomLine/2,YDim] (which can be negative, zero, or positive) and has a length of TopXDim along the positive x-axis.

Figure 429 — Trapezium profile

Attribute definitions

#	Attribute	Type	Description	G
4	BottomXDim	IfcPositiveLengthMeasure	The extent of the bottom line measured along the implicit x-axis.	X
5	TopXDim	IfcPositiveLengthMeasure	The extent of the top line measured along the implicit x-axis.	X
6	YDim	IfcPositiveLengthMeasure	The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis.	X
7	TopXOffset	IfcLengthMeasure	Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
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.	X
2	ProfileName	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.	X
	HasExternalReference	IfcExternalReferenceRelationship @RelatedResourceObjects	S[0:?]	Reference to external information, e.g. library, classification, or document information, which is associated with the profile. IFC4 CHANGE New inverse attribute	X
	HasProperties	IfcProfileProperties @ProfileDefinition	S[0:?]	Additional properties of the profile, for example mechanical properties. IFC4 CHANGE New inverse attribute	X
IfcParameterizedProfileDef
3	Position	IfcAxis2Placement2D	?	Position coordinate system of the parameterized profile definition. If unspecified, no translation and no rotation is applied.	X
IfcTrapeziumProfileDef
4	BottomXDim	IfcPositiveLengthMeasure		The extent of the bottom line measured along the implicit x-axis.	X
5	TopXDim	IfcPositiveLengthMeasure		The extent of the top line measured along the implicit x-axis.	X
6	YDim	IfcPositiveLengthMeasure		The extent of the distance between the parallel bottom and top lines measured along the implicit y-axis.	X
7	TopXOffset	IfcLengthMeasure		Offset from the beginning of the top line to the bottom line, measured along the implicit x-axis.	X

#	Concept	Template	Model View
IfcProfileDef
	Property Sets for Objects	Property Sets for Objects	General Usage

Formal representations

XML Specification

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

 <xs:complexType name="IfcTrapeziumProfileDef">

  <xs:complexContent>

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

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

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

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

    <xs:attribute name="TopXOffset" type="ifc:IfcLengthMeasure" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcTrapeziumProfileDef

 SUBTYPE OF (IfcParameterizedProfileDef);

  BottomXDim : IfcPositiveLengthMeasure;

  TopXDim : IfcPositiveLengthMeasure;

  YDim : IfcPositiveLengthMeasure;

  TopXOffset : IfcLengthMeasure;

END_ENTITY;

 EXPRESS-G diagram

	Trapezprofil - parametrische Definition
	Trapezium Profile Def
	Définition de section d'un profil trapézoïdal

Item	Change	Description
IFC2x3 to IFC4
IfcTrapeziumProfileDef
Position	MODIFIED	Instantiation changed to OPTIONAL.

IfcTrapeziumProfileDef

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations