IfcDirection

Natural language names
Richtung
Direction
Direction
Change log
ItemSPFXMLChangeDescription
IFC4 Addendum 1 4.0.1.0
    IfcDirection
      DirectionRatiosMODIFIEDType changed from REAL to IfcReal.
Semantic definitions at the entity
Entity definition

The IfcDirection provides a direction in two or three dimensional space depending on the number of DirectionRatio's provided. The IfcDirection does not imply a vector length, and the direction ratios does not have to be normalized.

NOTE  Definition according to ISO/CD 10303-42:1992
This entity defines a general direction vector in two or three dimensional space. The actual magnitudes of the components have no effect upon the direction being defined, only the ratios X:Y:Z or X:Y are significant.

NOTE  The components of this entity are not normalized. If a unit vector is required it should be normalized before use.

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

HISTORY  New entity in IFC1.0

Attribute definitions
#AttributeTypeCardinalityDescription G
1DirectionRatiosIfcRealL[2:3] The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3]) X
Dim
:=HIINDEX(DirectionRatios)
IfcDimensionCountThe space dimensionality of this class, defined by the number of real in the list of DirectionRatios. X
Formal Propositions
RuleDescription
MagnitudeGreaterZeroThe magnitude of the direction vector shall be greater than 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
IfcDirection
1DirectionRatiosIfcRealL[2:3] The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3]) X
Dim
:=HIINDEX(DirectionRatios)
IfcDimensionCountThe space dimensionality of this class, defined by the number of real in the list of DirectionRatios. X
Formal representations
XML Specification
 <xs:element name="IfcDirection" type="ifc:IfcDirection" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
 <xs:complexType name="IfcDirection">
  <xs:complexContent>
   <xs:extension base="ifc:IfcGeometricRepresentationItem">
    <xs:attribute name="DirectionRatios" use="optional">
     <xs:simpleType>
      <xs:restriction>
       <xs:simpleType>
        <xs:list itemType="ifc:IfcReal"/>
       </xs:simpleType>
       <xs:minLength value="2"/>
       <xs:maxLength value="3"/>
      </xs:restriction>
     </xs:simpleType>
    </xs:attribute>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcDirection
 SUBTYPE OF (IfcGeometricRepresentationItem);
  DirectionRatios : LIST [2:3] OF IfcReal;
 DERIVE
  Dim : IfcDimensionCount := HIINDEX(DirectionRatios);
 WHERE
  MagnitudeGreaterZero : SIZEOF(QUERY(Tmp <* DirectionRatios | Tmp <> 0.0)) > 0;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcStructuralCurveConnection IfcStructuralCurveMember IfcGridPlacementDirectionSelect IfcExtrudedAreaSolid IfcFixedReferenceSweptAreaSolid IfcAxis1Placement IfcAxis2Placement2D IfcAxis2Placement3D IfcAxis2PlacementLinear IfcCartesianTransformationOperator IfcCartesianTransformationOperator2D IfcCartesianTransformationOperator3D IfcOffsetCurve3D IfcSurfaceOfLinearExtrusion IfcVector IfcVectorOrDirection IfcLightSourceDirectional IfcLightSourceSpot IfcGeometricRepresentationContext IfcGeometricRepresentationSubContext

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