IfcVector

Natural language names
Vektor
Vector
Vecteur
Semantic definitions at the entity
Entity definition

An IfcVector is a geometric representation item having both a magnitude and direction. The magnitude of the vector is solely defined by the Magnitude attribute and the direction is solely defined by the Orientation attribute.

NOTE  The DirectionRatios of the Orientation attribute are not used to define the magnitude.

NOTE  Definition according to ISO/CD 10303-42:1992
The vector is defined in terms of the direction and magnitude of the vector. The value of the magnitude attribute defines the magnitude of the vector. The magnitude of the vector can not be reliable calculated from the components of the orientation attribute. This form of representation was selected to reduce problems with numerical instability. For example a vector of magnitude 2.0 mm and equally inclined to the coordinate axes could be represented with Orientation attribute of (1.0,1.0,1.0).

NOTE  Entity adapted from vector defined in ISO 10303-42.

HISTORY  New entity in IFC1.0

Attribute definitions
#AttributeTypeCardinalityDescription G
1OrientationIfcDirection The direction of the vector. X
2MagnitudeIfcLengthMeasure The magnitude of the vector. All vectors of Magnitude 0.0 are regarded as equal in value regardless of the orientation attribute. X
Dim
:=Orientation.Dim
IfcDimensionCountThe space dimensionality of this class, it is derived from Orientation X
Formal Propositions
RuleDescription
MagGreaterOrEqualZeroThe magnitude shall be positive or zero.
Inherited definitions from supertypes
Entity inheritance IfcGeometricRepresentationItem IfcRepresentationItem
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
IfcVector
1OrientationIfcDirection The direction of the vector. X
2MagnitudeIfcLengthMeasure The magnitude of the vector. All vectors of Magnitude 0.0 are regarded as equal in value regardless of the orientation attribute. X
Dim
:=Orientation.Dim
IfcDimensionCountThe space dimensionality of this class, it is derived from Orientation X
Formal representations
XML Specification
 <xs:element name="IfcVector" type="ifc:IfcVector" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
 <xs:complexType name="IfcVector">
  <xs:complexContent>
   <xs:extension base="ifc:IfcGeometricRepresentationItem">
    <xs:sequence>
     <xs:element name="Orientation" type="ifc:IfcDirection" nillable="true"/>
    </xs:sequence>
    <xs:attribute name="Magnitude" type="ifc:IfcLengthMeasure" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcVector
 SUBTYPE OF (IfcGeometricRepresentationItem);
  Orientation : IfcDirection;
  Magnitude : IfcLengthMeasure;
 DERIVE
  Dim : IfcDimensionCount := Orientation.Dim;
 WHERE
  MagGreaterOrEqualZero : Magnitude >= 0.0;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcLine IfcSurfaceOfLinearExtrusion IfcVectorOrDirection IfcFillAreaStyleTiles IfcHatchLineDistanceSelect

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