|modifications||attributes CrossSectionPositions definition||Changed from list[2:?] of IfcDistanceExpression to list[2:?] of IfcCurveMeasureSelect|
An IfcSectionedSolidHorizontal is a solid model constructed by sweeping potentially varying cross sections along a curve horizontally.
The solid is generated by sweeping the CrossSections between CrossSectionPositions with linear interpolation of profile points, where the profile normal agrees with the tangent of the Directrix, the profile X axis is oriented perpendicularly to the left of the Directrix (same direction as LateralOffset at IfcPointByDistanceExpression) as facing forward along the directrix, and the profile Y axis is oriented upwards according to FixedAxisVertical.
For sections having cross-section rotated according to a single super-elevation, IfcDerivedProfileDef may be used to indicate such rotation with each ParentProfile referring to the same underlying profile. For sections having cross-section transformed according to multiple super-elevations with points varying independently, each profile may be of a different instance but of same type (e.g. IfcArbitraryClosedProfileDef), and may optionally have cross section points associated to string lines (“guide curves”) using IfcIndexedPolyCurve with IfcCartesianPointList2DLabelled.
Figure 1 illustrates four girders of a bridge having a constant parameterized profile, two guardrails having a constant arbitrary profile (one of them mirrored), and a bridge deck having a variable arbitrary profile.
|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.
|Dim||INVALID||The space dimensionality of this class, it is always 3.|
|1||Directrix||IfcCurve||The curve used to define the sweeping operation.|
|2||CrossSections||LIST [2:?] OF IfcProfileDef||List of cross sections in sequential order along the Directrix.|
|3||CrossSectionPositions||LIST [2:?] OF IfcAxis2PlacementLinear||List of distance expressions in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.|
|4||FixedAxisVertical||IfcBoolean||Indicates whether Sections are oriented with the Y axis of each profile facing upwards in +Z direction (True), or vertically perpendicular to the Directrix varying according to slope (False).|
ENTITY IfcSectionedSolidHorizontal SUBTYPE OF (IfcSectionedSolid); CrossSectionPositions : LIST [2:?] OF IfcAxis2PlacementLinear; FixedAxisVertical : IfcBoolean; WHERE CorrespondingSectionPositions : SIZEOF(CrossSections) = SIZEOF(CrossSectionPositions); NoLongitudinalOffsets : SIZEOF(QUERY(temp <* CrossSectionPositions | EXISTS(temp.Location.OffsetLongitudinal))) = 0; END_ENTITY;