Distance Expression |

Item | SPF | XML | Change | Description |
---|---|---|---|---|

IFC4x1 Release Candidate 3 |
||||

IfcDistanceExpression | ADDED |

# | Attribute | Type | Cardinality | Description | G |
---|---|---|---|---|---|

1 | DistanceAlong | IfcLengthMeasure | The distance along the basis curve, measured according to projection in the horizontal plane if AlongHorizontal is True, or according to 3D distance otherwise. If the basis curve refers to IfcAlignmentCurve and AlongHorizontal is True, then this measurement directly corresponds to IfcAlignment2DHorizontal. | X | |

2 | OffsetLateral | IfcLengthMeasure | ? | Offset horizontally perpendicular to the basis curve, where positive values indicate to the left of the basis curve as facing in the direction of the basis curve, and negative values indicate to the right. If DistanceAlong coincides with a point of tangential discontinuity (within precision limits), then the tangent of the previous segment governs. | X |

3 | OffsetVertical | IfcLengthMeasure | ? | Offset vertical to the basis curve where positive values indicate vertically upwards in global coordinates at DistanceAlong, regardless of the slope of the basis curve at such point. | X |

4 | OffsetLongitudinal | IfcLengthMeasure | ? | Offset parallel to the basis curve after applying DistanceAlong, OffsetLateral, and OffsetVertical to reach locations for the case of a tangentially discontinuous basis curve. | X |

5 | AlongHorizontal | IfcBoolean | ? | Indicates whether DistanceAlong is measured according to horizontal projection of distance (if True), or 3D distance (if False or unset). | X |

# | Attribute | Type | Cardinality | Description | G |
---|---|---|---|---|---|

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 IFC4 CHANGE The inverse attribute | 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 | X | |

IfcGeometricRepresentationItem | |||||

IfcDistanceExpression | |||||

1 | DistanceAlong | IfcLengthMeasure | The distance along the basis curve, measured according to projection in the horizontal plane if AlongHorizontal is True, or according to 3D distance otherwise. If the basis curve refers to IfcAlignmentCurve and AlongHorizontal is True, then this measurement directly corresponds to IfcAlignment2DHorizontal. | X | |

2 | OffsetLateral | IfcLengthMeasure | ? | Offset horizontally perpendicular to the basis curve, where positive values indicate to the left of the basis curve as facing in the direction of the basis curve, and negative values indicate to the right. If DistanceAlong coincides with a point of tangential discontinuity (within precision limits), then the tangent of the previous segment governs. | X |

3 | OffsetVertical | IfcLengthMeasure | ? | Offset vertical to the basis curve where positive values indicate vertically upwards in global coordinates at DistanceAlong, regardless of the slope of the basis curve at such point. | X |

4 | OffsetLongitudinal | IfcLengthMeasure | ? | Offset parallel to the basis curve after applying DistanceAlong, OffsetLateral, and OffsetVertical to reach locations for the case of a tangentially discontinuous basis curve. | X |

5 | AlongHorizontal | IfcBoolean | ? | Indicates whether DistanceAlong is measured according to horizontal projection of distance (if True), or 3D distance (if False or unset). | X |

` <xs:element name="IfcDistanceExpression" type="ifc:IfcDistanceExpression" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>`

<xs:complexType name="IfcDistanceExpression">

<xs:complexContent>

<xs:extension base="ifc:IfcGeometricRepresentationItem">

<xs:attribute name="DistanceAlong" type="ifc:IfcLengthMeasure" use="optional"/>

<xs:attribute name="OffsetLateral" type="ifc:IfcLengthMeasure" use="optional"/>

<xs:attribute name="OffsetVertical" type="ifc:IfcLengthMeasure" use="optional"/>

<xs:attribute name="OffsetLongitudinal" type="ifc:IfcLengthMeasure" use="optional"/>

<xs:attribute name="AlongHorizontal" type="ifc:IfcBoolean" use="optional"/>

</xs:extension>

</xs:complexContent>

</xs:complexType>

```
ENTITY IfcDistanceExpression
```

SUBTYPE OF (IfcGeometricRepresentationItem)**;**

DistanceAlong : IfcLengthMeasure;

OffsetLateral : OPTIONAL IfcLengthMeasure;

OffsetVertical : OPTIONAL IfcLengthMeasure;

OffsetLongitudinal : OPTIONAL IfcLengthMeasure;

AlongHorizontal : OPTIONAL IfcBoolean;

END_ENTITY;

References: IfcLinearPlacement IfcSectionedSolidHorizontal IfcOffsetCurveByDistances