IfcPointOnCurve

BACnet MVD

#### IfcPointOnCurve

Natural language names

| Punkt auf einer Kurve
| Point On Curve
| Point de courbe

##### Semantic definitions at the entity

Entity definition

The IfcPointOnCurve is a point defined by a parameter value of its defining curve.

> NOTE Definition according to ISO/CD 10303-42:1992
> A point on curve is a point which lies on a curve. The point is determined by evaluating the curve at a specific parameter value. The coordinate space dimensionality of the point is that of the basis curve.

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

> HISTORY New entity in IFC2x2.

Informal Propositions:

1. The value of the point parameter shall not be outside the parametric range of the curve.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | BasisCurve | IfcCurve |  | The curve to which point parameter relates. |  | X
2 | PointParameter | IfcParameterValue |  | The parameter value of the point location. |  | X
| Dim :=BasisCurve.Dim | IfcDimensionCount |  | The space dimensionality of this class, determined by the space dimensionality of the basis curve. |  | 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
IfcPointOnCurve
1 | BasisCurve | IfcCurve |  | The curve to which point parameter relates. |  | X
2 | PointParameter | IfcParameterValue |  | The parameter value of the point location. |  | X
| Dim :=BasisCurve.Dim | IfcDimensionCount |  | The space dimensionality of this class, determined by the space dimensionality of the basis curve. |  | X

##### Formal representations

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

EXPRESS-G diagram

`

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