4.1.7.1.1 Alignment Geometry

Supported shape representations of IfcAlignment are:

• IfcCompositeCurve as a 2D horizontal alignment (represented by its horizontal alignment segments), without a vertical layout.
• IfcGradientCurve as a 3D horizontal and vertical alignment (represented by their alignment segments), without a cant layout.
• IfcSegmentedReferenceCurve as a 3D curve defined relative to an IfcGradientCurve to incorporate the application of cant.
• IfcOffsetCurveByDistances as a 2D or 3D curve defined relative to an IfcGradientCurve or another IfcOffsetCurveByDistances.
• IfcPolyline or IfcIndexedPolyCurve as a 3D alignment by a 3D polyline representation (such as coming from a survey).
• IfcPolyline or IfcIndexedPolyCurve as a 2D horizontal alignment by a 2D polyline representation (such as in very early planning phases or as a map representation).

Refer to the following Alignment Geometry concept templates to know which RepresentationIdentifier and RepresentationType shall be set for the different representations and the different layouts' configurations of IfcAlignment.