8.8.3.34 IfcSectionedSolidHorizontal

8.8.3.34.1 Semantic definition

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 between profile points with the same tag along the directrix. The profile normal is derived from the associated IfcAxis2PlacementLinear, not necessarily the tangent of the Directrix. The profile X axis is the direction of RefDirection from IfcAxis2PlacementLinear, and the profile Y axis is the direction of Axis.

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") by matching labels using IfcIndexedPolyCurve with IfcCartesianPointList2D.TagList.

Figure 8.8.3.34.A 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.

spatial structure — Figure 8.8.3.34.A — Sectioned solid horizontal

IfcSectionedSolidHorizontal1 — Figure 8.8.3.34.B — Side View showing multiple CrossSectionPositions

IfcSectionedSolidHorizontal2 — Figure 8.8.3.34.C — Example Shape in red based on two Cross Sections both not starting at the beginning or end and different in shape.

Informal Propositions:

No two consecutive sections shall intersect.
If the type of sections is not IfcParameterizedProfileDef (i.e. an arbitrary profile), then the number of points and edges should be the same for two consecutive profiles
If the directrix is not tangent continuous, the resulting solid is created by a miter at half angle between the two segments.
Very sharp edges may result in nearly impossible miter; implementer agreements may define acceptable limits for tangent discontinuity or require the directrix to be tangent continuous.
The directrix shall not intersect

8.8.3.34.2 Entity inheritance

8.8.3.34.3 Attributes

#	Attribute	Type	Description
IfcRepresentationItem (2)
	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.
IfcSolidModel (1)
*	Dim	IfcDimensionCount	This attribute is formally derived. `3` The space dimensionality of this class, it is always 3.
IfcSectionedSolid (2)
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.
Click to show 5 hidden inherited attributes Click to hide 5 inherited attributes
IfcSectionedSolidHorizontal (1)
3	CrossSectionPositions	LIST [2:?] OF IfcAxis2PlacementLinear	Position coordinate systems in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.

Table 8.8.3.34.D

8.8.3.34.4 Formal propositions

Name	Description
CorrespondingSectionPositions	The set of cross sections and the set of cross section positions shall be of the same size.
`SIZEOF(CrossSections) = SIZEOF(CrossSectionPositions)`
NoLongitudinalOffsets	Distance expressions must not use longitudinal offsets.
`SIZEOF(QUERY(temp <* CrossSectionPositions \| EXISTS(temp.Location.OffsetLongitudinal))) = 0`

Table 8.8.3.34.E

8.8.3.34.5 Formal representation

ENTITY IfcSectionedSolidHorizontal
 SUBTYPE OF (IfcSectionedSolid);
	CrossSectionPositions : LIST [2:?] OF IfcAxis2PlacementLinear;
 WHERE
	CorrespondingSectionPositions : SIZEOF(CrossSections) = SIZEOF(CrossSectionPositions);
	NoLongitudinalOffsets : SIZEOF(QUERY(temp <* CrossSectionPositions | EXISTS(temp.Location.OffsetLongitudinal))) = 0;
END_ENTITY;

8.8.3.34.6 References

IfcSectionedSolid