IfcSectionedSolidHorizontal

Item	SPF	XML	Change	Description
IFC4x1 Final 4.1.0.0
IfcSectionedSolidHorizontal			ADDED
IFC4x1 Final 4.1.0.0
IfcSectionedSolidHorizontal			ADDED

Semantic definitions at the entity

Entity 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 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 IfcDistanceExpression) 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 344 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.

Figure 344 — Sectioned solid horizontal

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

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
3	CrossSectionPositions	IfcDistanceExpression	L[2:?]	List of distance expressions in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.	X
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).	X

Formal Propositions

Rule	Description
CorrespondingSectionPositions	The set of cross sections and the set of cross section positions shall be of the same size.
NoLongitudinalOffsets	Distance expressions must not use longitudinal offsets.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	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 LayerAssignments has been added. IFC4 CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.	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 StyledByItem has been added.	X
IfcGeometricRepresentationItem
IfcSolidModel
	Dim :=3	IfcDimensionCount		The space dimensionality of this class, it is always 3.	X
IfcSectionedSolid
1	Directrix	IfcCurve		The curve used to define the sweeping operation.	X
2	CrossSections	IfcProfileDef	L[2:?]	List of cross sections in sequential order along the Directrix.	X
IfcSectionedSolidHorizontal
3	CrossSectionPositions	IfcDistanceExpression	L[2:?]	List of distance expressions in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.	X
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).	X

Formal representations

XML Specification

 <xs:element name="IfcSectionedSolidHorizontal" type="ifc:IfcSectionedSolidHorizontal" substitutionGroup="ifc:IfcSectionedSolid" nillable="true"/>

 <xs:complexType name="IfcSectionedSolidHorizontal">

  <xs:complexContent>

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

    <xs:sequence>

     <xs:element name="CrossSectionPositions">

      <xs:complexType>

       <xs:sequence>

        <xs:element ref="ifc:IfcDistanceExpression" minOccurs="2" maxOccurs="unbounded"/>

       </xs:sequence>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcDistanceExpression"/>

       <xs:attribute ref="ifc:cType" fixed="list"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

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

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcSectionedSolidHorizontal

 SUBTYPE OF (IfcSectionedSolid);

  CrossSectionPositions : LIST [2:?] OF IfcDistanceExpression;

  FixedAxisVertical : IfcBoolean;

 WHERE

  CorrespondingSectionPositions : SIZEOF(CrossSections) = SIZEOF(CrossSectionPositions);
  NoLongitudinalOffsets : SIZEOF(QUERY(temp <* CrossSectionPositions | EXISTS(temp.OffsetLongitudinal))) = 0;
END_ENTITY;

 EXPRESS-G diagram