IfcPointOnSurface

BACnet MVD

#### IfcPointOnSurface

Natural language names

| Punkt auf einer Oberfläche
| Point On Surface
| Point de surface

##### Semantic definitions at the entity

Entity definition

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.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | BasisSurface | IfcSurface |  | The surface to which the parameter values relate. |  | X
2 | PointParameterU | IfcParameterValue |  | The first parameter value of the point location. |  | X
3 | PointParameterV | IfcParameterValue |  | The second parameter value of the point location. |  | X
| Dim :=BasisSurface.Dim | IfcDimensionCount |  | The space dimensionality of this class, determined by the space dimensionality of the basis surface. |  | X

##### 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
IfcPoint
IfcPointOnSurface
1 | BasisSurface | IfcSurface |  | The surface to which the parameter values relate. |  | X
2 | PointParameterU | IfcParameterValue |  | The first parameter value of the point location. |  | X
3 | PointParameterV | IfcParameterValue |  | The second parameter value of the point location. |  | X
| Dim :=BasisSurface.Dim | IfcDimensionCount |  | The space dimensionality of this class, determined by the space dimensionality of the basis surface. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcPointOnSurface" type="ifc:IfcPointOnSurface" substitutionGroup="ifc:IfcPoint" nillable="true"/>
<xs:complexType name="IfcPointOnSurface">
<xs:complexContent>
<xs:extension base="ifc:IfcPoint">
<xs:sequence>
<xs:element name="BasisSurface" type="ifc:IfcSurface" nillable="true"/>
</xs:sequence>
<xs:attribute name="PointParameterU" type="ifc:IfcParameterValue" use="optional"/>
<xs:attribute name="PointParameterV" type="ifc:IfcParameterValue" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPointOnSurface
SUBTYPE OF (IfcPoint);
BasisSurface : IfcSurface;
PointParameterU : IfcParameterValue;
PointParameterV : IfcParameterValue;
DERIVE
Dim : IfcDimensionCount := BasisSurface.Dim;
END_ENTITY;

EXPRESS-G diagram

`

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