#### IfcCartesianPoint

Natural language names

##### Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: A point defined by its coordinates in a two or three dimensional rectangular Cartesian coordinate system, or in a two dimensional parameter space. The entity is defined in a two or three dimensional space.

The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem). The WR1 was added to constrain the usage of IfcCartesianPoint in the context of IFC geometry. For the purpose of defining geometry in IFC only two and three dimensional Cartesian points are used.

> NOTE: Corresponding STEP entity : cartesian_point, please refer to ISO/IS 10303-42:1994, p. 23 for the final definition of the formal standard.

> HISTORY: New entity in IFC Release 1.0

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
1 | Coordinates | IfcLengthMeasure | L[1:3] | The first, second, and third coordinate of the point location. If placed in a two or three dimensional rectangular Cartesian coordinate system, Coordinates[1] is the X coordinate, Coordinates[2] is the Y coordinate, and Coordinates[3] is the Z coordinate. | X
| Dim :=HIINDEX(Coordinates) | IfcDimensionCount | [1:1] | The space dimensionality of this class, determined by the number of coordinates in the List of Coordinates. | X

Formal Propositions

Rule | Description
--- | ---
WR1 | Only two or three dimensional points shall be used for the purpose of defining geometry in this IFC Resource.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRepresentationItem
IfcGeometricRepresentationItem
IfcPoint
IfcCartesianPoint
1 | Coordinates | IfcLengthMeasure | L[1:3] | The first, second, and third coordinate of the point location. If placed in a two or three dimensional rectangular Cartesian coordinate system, Coordinates[1] is the X coordinate, Coordinates[2] is the Y coordinate, and Coordinates[3] is the Z coordinate. | X
| Dim :=HIINDEX(Coordinates) | IfcDimensionCount | [1:1] | The space dimensionality of this class, determined by the number of coordinates in the List of Coordinates. | X

##### Formal representations

XSD Specification
`<xs:element name="IfcCartesianPoint" type="ifc:IfcCartesianPoint" substitutionGroup="ifc:IfcPoint" nillable="true"/>
<xs:complexType name="IfcCartesianPoint">
<xs:complexContent>
<xs:extension base="ifc:IfcPoint">
<xs:attribute name="Coordinates" use="optional">
<xs:simpleType>
<xs:restriction>
<xs:simpleType>
<xs:list itemType="ifc:IfcLengthMeasure"/>
</xs:simpleType>
<xs:maxLength value="3"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcCartesianPoint
SUBTYPE OF (IfcPoint);
Coordinates : LIST [1:3] OF IfcLengthMeasure;
DERIVE
Dim : IfcDimensionCount := HIINDEX(Coordinates);
WHERE
WR1 : HIINDEX(Coordinates) >= 2;
END_ENTITY;

EXPRESS-G diagram

`

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