IFC 4.3.x development

8.8.3.30 IfcRevolvedAreaSolidTapered

Change log

IFC4

added

8.8.3.30.1 Semantic definitions at the entity

IfcRevolvedAreaSolidTapered is defined by revolving a cross section along a circular arc. The cross section may change along the revolving sweep from the shape of the start cross section into the shape of the end cross section. Corresponding vertices of the start and end cross sections are then connected. The bounded surface may have holes which will sweep into holes in the solid.

The rotation axis is defined by:

  • Start point: SELF\IfcSweptAreaSolid.Position.Location
  • Direction: SELF\IfcRevolvedAreaSolid.Axis
  • Rotation axis: SELF\IfcRevolvedAreaSolid.AxisLine, created from start point and direction by appying a 1 unit magnitude.
  • Orientation: Positive angles are applied clockwise when looking into the positive direction of the rotation axis.

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 rotation axis lies in the plane of the start cross section but shall not intersect the interior of the start cross section.

The end cross section is defined by EndSweptArea:

  • A bounded planar surface lying in the XY plane of the position coordinate system defined by rotating the start position coordinates provided by SELF\IfcSweptAreaSolid.Position around the rotation axis by the angle given by SELF\IfcRevolvedAreaSolid.Angle.
    • The end cross section is topologically similar to the start cross section (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.

The solid is generated by transforming the start cross section into to end cross section. A start face, an end face (each defined by start and end cross 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. The ruled surfaces are constructed in the cylindrical coordinate space defined by the supertype IfcRevolvedAreaSolid.

HISTORY  New entity in IFC4.

Informal Propositions:

  1. Mirroring within IfcDerivedProfileDef.Operator shall not be used

8.8.3.30.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item 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.
IfcGeometricRepresentationItem
IfcSolidModel
Dim INVALID The space dimensionality of this class, it is always 3.
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.
2 Position OPTIONAL 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.
IfcRevolvedAreaSolid
3 Axis IfcAxis1Placement Axis about which revolution will take place.
4 Angle IfcPlaneAngleMeasure The angle through which the sweep will be made. This angle is measured from the plane of the swept area provided by the XY plane of the position coordinate system.
AxisLine INVALID The line of the axis of revolution.
IfcRevolvedAreaSolidTapered
5 EndSweptArea IfcProfileDef

8.8.3.30.2 Entity inheritance

dot_inheritance IfcRevolvedAreaSolidTapered IfcRevolvedAreaSolidTapered IfcRevolvedAreaSolid IfcRevolvedAreaSolid IfcRevolvedAreaSolidTapered->IfcRevolvedAreaSolid IfcSweptAreaSolid IfcSweptAreaSolid IfcRevolvedAreaSolid->IfcSweptAreaSolid IfcExtrudedAreaSolid IfcExtrudedAreaSolid IfcExtrudedAreaSolid->IfcSweptAreaSolid IfcSolidModel IfcSolidModel IfcSweptAreaSolid->IfcSolidModel IfcDirectrixCurveSweptAreaSolid IfcDirectrixCurveSweptAreaSolid IfcDirectrixCurveSweptAreaSolid->IfcSweptAreaSolid IfcSolidModel_children 4 more... IfcSolidModel_children->IfcSolidModel IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcSolidModel->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.8.3.30.3 Formal representations

ENTITY IfcRevolvedAreaSolidTapered
 SUBTYPE OF (IfcRevolvedAreaSolid);
	EndSweptArea : IfcProfileDef;
 WHERE
	CorrectProfileAssignment : IfcTaperedSweptAreaProfiles(SELF\IfcSweptAreaSolid.SweptArea, SELF.EndSweptArea);
END_ENTITY;