added |

The *IfcAxis2PlacementLinear* provides location and orientation to place items in a three-dimensional space confined to the context of a curve. Relative placement axes (Axis and RefDirection) are relative to the curve used for linear referencing provided in *IfcPlacement* *Location* (*IfcPointByDistanceExpression* *BasisCurve*), maintaining the relationship to the tangent of the curve.

# | Attribute | Type | Description |
---|---|---|---|

IfcRepresentationItem | |||

LayerAssignment | SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems | 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. | |

StyledByItem | SET [0:1] OF IfcStyledItem FOR Item | 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. | |

IfcGeometricRepresentationItem | |||

IfcPlacement | |||

1 | Location | IfcPoint | The geometric position of a reference point, such as the center of a circle, of the item to be located. |

Dim | INVALID | The space dimensionality of this class, derived from the dimensionality of the location. | |

IfcAxis2PlacementLinear | |||

2 | Axis | OPTIONAL IfcDirection | The exact direction of the local Z Axis. |

3 | RefDirection | OPTIONAL IfcDirection | The direction used to determine the direction of the local X Axis. In case both Axis and RefDirection are set and not perpendicular an adjustment is necessary to maintain orthogonality to the Axis direction. If RefDirection is omitted, the direction is taken from the curve tangent at Location. |

ENTITY IfcAxis2PlacementLinear SUBTYPE OF (IfcPlacement); Axis : OPTIONAL IfcDirection; RefDirection : OPTIONAL IfcDirection; WHERE WR1 : 'IFC4X3_DEV_a1492713.IFCPOINTBYDISTANCEEXPRESSION' IN TYPEOF(SELF\IfcPlacement.Location); WR2 : (NOT (EXISTS (Axis))) OR (NOT (EXISTS (RefDirection))) OR (IfcCrossProduct(Axis,RefDirection).Magnitude > 0.0); END_ENTITY;