IFC 4.3.x development

8.9.3.51 IfcPointOnSurface

8.9.3.51.1 Semantic definitions at the entity

The IfcPointOnSurface is a point defined by two parameter value of its defining surface.

NOTE  Definition according to ISO/CD 10303-42:1992
A point on surface is a point which lies on a parametric surface. The point is determined by evaluating the surface at a particular pair of parameter values.

NOTE  Entity adapted from point_on_surface in ISO 10303-42.

HISTORY  New entity in IFC2x2.

Informal Propositions:

  1. The parametric values specified for u and v shall not be outside the parametric range of the basis surface.

8.9.3.51.1 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
IfcPoint
IfcPointOnSurface
1 BasisSurface IfcSurface The surface to which the parameter values relate.
2 PointParameterUIfcParameterValue The first parameter value of the point location.
3 PointParameterVIfcParameterValue The second parameter value of the point location.
Dim INVALID The space dimensionality of this class, determined by the space dimensionality of the basis surface.

8.9.3.51.2 Entity inheritance

dot_inheritance IfcPointOnSurface IfcPointOnSurface IfcPoint IfcPoint IfcPointOnSurface->IfcPoint IfcPoint_children 3 more... IfcPoint_children->IfcPoint IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcPoint->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.51.3 Formal representations

ENTITY IfcPointOnSurface
 SUBTYPE OF (IfcPoint);
	BasisSurface : IfcSurface;
	PointParameterU : IfcParameterValue;
	PointParameterV : IfcParameterValue;
 DERIVE
	 Dim : IfcDimensionCount := BasisSurface.Dim;
END_ENTITY;