IfcExtrudedAreaSolidTapered

Item	SPF	XML	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcExtrudedAreaSolidTapered			ADDED

Semantic definitions at the entity

Entity definition

IfcExtrudedAreaSolidTapered is defined by sweeping a cross section along a linear spine. The cross section may change along the sweep from the shape of the start cross section into the shape of the end cross section. The resulting solid is bounded by three or more faces: A start face, an end face (each defined by start and end planes and sections), and one or more lateral faces. Each lateral face is a ruled surface defined by a pair of corresponding edges of the start and end section.

NOTE Given that the start and end section is provided by a polygon, the corresponding vertices of the start and end cross section are connected, forming a quadrilateral polygon between each pair of corresponding vertices. The surface defined by the bounding quadrilateral polygon is a ruled surface, that could be approximated by triangulation.

The linear spine is defined by:

Start point: SELF\IfcSweptAreaSolid.Position.Location
Direction: SELF\IfcExtrudedAreaSolid.ExtrudedDirection
Distance: SELF\IfcExtrudedAreaSolid.Depth

The start cross section is defined by SELF\IfcSweptAreaSolid.SweptArea:

A bounded planar surface lying in the XY plane of the position coordinate system defined by SELF\IfcSweptAreaSolid.Position.P[1] and SELF\IfcSweptAreaSolid.Position.P[2]
The linear spine starts at the plane of the start cross section. The spine is not necessarily perpendicular to the plane.

The end cross section is defined by EndSweptArea:

A bounded planar surface lying in the XY plane of the position coordinate system defined by translating the start position coordinates provided by SELF\IfcSweptAreaSolid.Position along the spine direction by the spine distance. The plane of the end cross section is coplanar to the plane of the start cross section.
- The end cross section is topologically similar to the start cross section (i.e. having the same number of vertices and edges).
- The end cross section can either be defined by the same paramteric profile using different parameter values, or by a 2D Cartesian transformation of the start profile within the end cross section plane.

In case of two parameterized profiles the shape is constructed as follows:

The end profile, defined by a cross section based on the same profile paramterization as the start profile, is translated by the spine distance along the spine direction.
It may be shifted within the XY plane of the end postion coordinate system and may be twisted using the rotation parameter.
The shift and rotation parameter are provided by the end cross section being of type IfcParameterizedProfileDef, where
- Shift is EndSweptArea\IfcParameterizedProfileDef.Position.Location
- Rotation is EndSweptArea\IfcParameterizedProfileDef.Position.RefDirection
Corresponding vertices of the start and end cross section are connected. Lateral faces are constructed as ruled surfaces between corresponding edges of start and end cross section.

In case of Cartesian transformation of the start cross section the shape is constructed as follows:

The cross section curve, which starts as a curve in the XY plane of the position coordinate system, is first scaled about the origin by the scale parameter. It is then translated by the spine distance along the spine direction. It maybe twisted by using the rotation parameter.
The scale and rotation parameter are provided by the end cross section being of type IfcDerivedProfileDef, where
- Scale is EndSweptArea\IfcDerivedProfileDef.Operator.Scale
- Rotation is EndSweptArea\IfcDerivedProfileDef.Operator.Axis1
Corresponding vertices of the start and end cross section are connected. Lateral faces are constructed as ruled surfaces between corresponding edges of start and end cross section.

HISTORY New entity in IFC4.

Informal Propositions:

Mirroring within IfcDerivedProfileDef.Operator shall not be used

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
5	EndSweptArea	IfcProfileDef		The surface defining the end of the swept area. It is given as a profile definition. The position coordinate system of the EndSwptArea is generated by translating the SELF\IfcSweptAreaSolid.Position along the SELF\IfcExtrudedAreaSolid.ExtrudedDirection by the distance of SELF\IfcExtrudedAreaSolid.Depth.	X

Formal Propositions

Rule	Description
CorrectProfileAssignment	The SweptArea as start profile and the EndSweptArea as end profile shall be compatible.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. IFC2x3 CHANGE The inverse attribute LayerAssignments has been added. IFC4 CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. IFC2x3 CHANGE The inverse attribute StyledByItem has been added.	X
IfcGeometricRepresentationItem
IfcSolidModel
	Dim :=3	IfcDimensionCount		The space dimensionality of this class, it is always 3.	X
IfcSweptAreaSolid
1	SweptArea	IfcProfileDef		The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system.	X
2	Position	IfcAxis2Placement3D	?	Position coordinate system for the resulting swept solid of the sweeping operation. The position coordinate system allows for re-positioning of the swept solid. If not provided, the swept solid remains within the position as determined by the cross section or by the directrix used for the sweeping operation. IFC4 CHANGE The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.	X
IfcExtrudedAreaSolid
3	ExtrudedDirection	IfcDirection		The direction in which the surface, provided by SweptArea is to be swept.	X
4	Depth	IfcPositiveLengthMeasure		The distance the surface is to be swept along the ExtrudedDirection.	X
IfcExtrudedAreaSolidTapered
5	EndSweptArea	IfcProfileDef		The surface defining the end of the swept area. It is given as a profile definition. The position coordinate system of the EndSwptArea is generated by translating the SELF\IfcSweptAreaSolid.Position along the SELF\IfcExtrudedAreaSolid.ExtrudedDirection by the distance of SELF\IfcExtrudedAreaSolid.Depth.	X

Formal representations

XML Specification

 <xs:element name="IfcExtrudedAreaSolidTapered" type="ifc:IfcExtrudedAreaSolidTapered" substitutionGroup="ifc:IfcExtrudedAreaSolid" nillable="true"/>

 <xs:complexType name="IfcExtrudedAreaSolidTapered">

  <xs:complexContent>

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

    <xs:sequence>

     <xs:element name="EndSweptArea" type="ifc:IfcProfileDef" nillable="true"/>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcExtrudedAreaSolidTapered

 SUBTYPE OF (IfcExtrudedAreaSolid);

  EndSweptArea : IfcProfileDef;

 WHERE

  CorrectProfileAssignment : IfcTaperedSweptAreaProfiles(SELF\IfcSweptAreaSolid.SweptArea, SELF.EndSweptArea);
END_ENTITY;

 EXPRESS-G diagram

	Sich verjüngender Festkörper - aus extrudierter Fläche
	Extruded Area Solid Tapered