IFC 4.3.x development

8.9.3.49 IfcPlane

8.9.3.49.1 Semantic definitions at the entity

The planar surface is an unbounded surface in the direction of x and y. Bounded planar surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a plane.

NOTE  Definition according to ISO/CD 10303-42:1992
A plane is an unbounded surface with a constant normal. A plane is defined by a point on the plane and the normal direction to the plane. The data is to be interpreted as follows:

   C = Position.Location
   x = Position.P[1]
   y = Position.P[2]
   z = Position.P[3] => normal to plane
and the surface is parameterized as:

formula where the parametric range is -∞ < u,v < ∞. In the above parameterization the length unit for the unit vectors x and y is derived from the context of the plane.

NOTE  A rectangular bounded planar surface can be defined by an IfcRectangularTrimmedSurface with BasisSurface being the plane and U1 = left bound in x, U2 = right bound in x, V_1 = lower bound in y, _V2 = upper bound in y if viewed into the direction of the negative normal. (assuming the Usense and Vsense agree to the sense of the basis surface).

The inherited attributes are interpreted as

NOTE  Entity adapted from plane in ISO 10303-42.

HISTORY  New entity in IFC1.5

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

> IFC4 CHANGE Derived attribute promoted from subtypes.
IfcElementarySurface
1 Position IfcAxis2Placement3D The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface.

8.9.3.49.1 Entity inheritance

dot_inheritance IfcPlane IfcPlane IfcElementarySurface IfcElementarySurface IfcPlane->IfcElementarySurface IfcElementarySurface_children 3 more... IfcElementarySurface_children->IfcElementarySurface IfcSurface IfcSurface IfcElementarySurface->IfcSurface IfcSurface_children 3 more... IfcSurface_children->IfcSurface IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcSurface->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.49.2 Formal representations

ENTITY IfcPlane
 SUBTYPE OF (IfcElementarySurface);
END_ENTITY;