﻿ IfcPolyline

#### IfcPolyline

Natural language names
 Polylinie Polyline Polyligne
##### Semantic definitions at the entity
Entity definition

The IfcPolyline is a bounded curve with only linear segments defined by a list of Cartesian points. If the first and the last Cartesian point in the list are identical, then the polyline is a closed curve, otherwise it is an open curve.

EXAMPLE  Figure 394 illustrates a bounded IfcPolyline and shows the parametric length of each segment and of the total polyline. The parametric length of the entire polyline is n - 1, where n is the number of Points.
 Figure 394 — Bounded IfcPolyline with parametric length
NOTE  Definition according to ISO/CD 10303-42:1992
A polyline is a bounded curve of n - 1 linear segments, defined by a list of n points, P1, P2 ... Pn. The i th segment of the curve is parameterized as follows:
for 1 ≤ in - 1
where i - 1 ≤ ui and with parametric range of 0 ≤ un - 1.
NOTE  Entity adapted from polyline in ISO 10303-42.
HISTORY  New entity in IFC1.0
Attribute definitions
#AttributeTypeCardinalityDescription G
1PointsIfcCartesianPointL[2:?] The points defining the polyline.X
Formal Propositions
RuleDescription
SameDimThe space dimensionality of all Points shall be the same.
##### Inherited definitions from supertypes
Entity inheritance
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@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
StyledByItemIfcStyledItem
@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
IfcCurve
Dim
:=IfcCurveDim(SELF)
IfcDimensionCountThe space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve. X
IfcBoundedCurve
IfcPolyline
1PointsIfcCartesianPointL[2:?] The points defining the polyline.X
##### Formal representations
XML Specification
``` <xs:element name="IfcPolyline" type="ifc:IfcPolyline" substitutionGroup="ifc:IfcBoundedCurve" nillable="true"/>  <xs:complexType name="IfcPolyline">   <xs:complexContent>    <xs:extension base="ifc:IfcBoundedCurve">     <xs:sequence>      <xs:element name="Points">       <xs:complexType>        <xs:sequence>         <xs:element ref="ifc:IfcCartesianPoint" minOccurs="2" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute ref="ifc:itemType" fixed="ifc:IfcCartesianPoint"/>        <xs:attribute ref="ifc:cType" fixed="list"/>        <xs:attribute ref="ifc:arraySize" use="optional"/>       </xs:complexType>      </xs:element>     </xs:sequence>    </xs:extension>   </xs:complexContent>  </xs:complexType> ```
EXPRESS Specification
``` ENTITY IfcPolyline  SUBTYPE OF (IfcBoundedCurve);   Points : LIST [2:?] OF IfcCartesianPoint;  WHERE   SameDim : SIZEOF(QUERY(Temp <* Points | Temp.Dim <> Points[1].Dim)) = 0;END_ENTITY;  EXPRESS-G diagram ```