8.9.3.70 IfcSurfaceOfRevolution

8.9.3.70.1 Semantic definition

The IfcSurfaceOfRevolution is a surface derived by rotating a curve about an axis.

The parameterization is as follows where the curve has a parameterization λ(u):

C = AxisPosition.Location V = AxisPosition.Z

In order to produce a single-valued surface with a complete revolution, the curve shall be such that when expressed in a cylindrical coordinate system (r,φ ,z) centred at C with an axis V, no two distinct parametric points on the curve shall have the same values for (r, z). For a surface of revolution the parametric range is 0 < u < 360 degree. The parameterization range for v is defined by referenced curve.
Figure 8.9.3.70.A

Informal Propositions

The surface shall not self-intersect
The swept curve shall not be coincident with the axis line for any finite part of its length.

8.9.3.70.2 Entity inheritance

8.9.3.70.3 Attributes

# Attribute Type Description

IfcRepresentationItem (2)

LayerAssignment

SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

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.

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.

IfcSurface (1)

Dim

IfcDimensionCount

This attribute is formally derived.

The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.

IfcSweptSurface (2)

SweptCurve

IfcProfileDef

The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system.

Position

OPTIONAL IfcAxis2Placement3D

Position coordinate system for the swept surface, provided by a profile definition within the XY plane of the Position coordinates. If not provided, the position of the profile being swept is determined by the object coordinate system. In this case, the swept surface is not repositioned.

Click to show 5 hidden inherited attributes

IfcSurfaceOfRevolution (2)

AxisPosition

IfcAxis1Placement

A point on the axis of revolution and the direction of the axis of revolution.

AxisLine

IfcLine

This attribute is formally derived.

 IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location, 
  IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0))

The line coinciding with the axis of revolution.

Table 8.9.3.70.B

8.9.3.70.4 Formal representation

 ENTITY IfcSurfaceOfRevolution
 SUBTYPE OF (IfcSweptSurface);
	AxisPosition : IfcAxis1Placement;
 DERIVE
	 AxisLine : IfcLine := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location, 
  IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0));
END_ENTITY;

8.9.3.70.5 References

IfcSweptSurface

	ENTITY IfcSurfaceOfRevolution
	SUBTYPE OF (IfcSweptSurface);
	AxisPosition : IfcAxis1Placement;
	DERIVE
	AxisLine : IfcLine := IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcCurve() \|\| IfcLine(AxisPosition.Location,
	IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcVector(AxisPosition.Z,1.0));
	END_ENTITY;