IfcPlane

BACnet MVD

#### IfcPlane

Natural language names

| Ebene Fläche
| Plane
| Plan

##### Semantic definitions at the entity

Entity definition

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:

> 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, V1 = 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

- SELF\IfcElementarySurface.Position defines the location and orientation of the planar surface.
- SELF\IfcElementarySurface.Position.Location defines a point on the planar surface.
- SELF\IfcElementarySurface.Position.P[3] defines the normal of the planar surface.

> NOTE Entity adapted from plane in ISO 10303-42.

> HISTORY New entity in IFC1.5

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
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

X

IfcGeometricRepresentationItem
IfcSurface

Dim
:=3

IfcDimensionCount

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

> IFC4 CHANGE Derived attribute promoted from subtypes.

X

X

IfcElementarySurface
1 | Position | IfcAxis2Placement3D |  | The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface. | X | X
IfcPlane

##### Formal representations

XML Specification
`<xs:element name="IfcPlane" type="ifc:IfcPlane" substitutionGroup="ifc:IfcElementarySurface" nillable="true"/>
<xs:complexType name="IfcPlane">
<xs:complexContent>
<xs:extension base="ifc:IfcElementarySurface"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPlane
SUBTYPE OF (IfcElementarySurface);
END_ENTITY;

EXPRESS-G diagram

`

References: IfcCurveBoundedPlane

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