IfcDirection

Semantic definitions at the entity

Entity definition

Definition from 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: Corresponding STEP entity: direction. Please refer to ISO/IS 10303-42:1994, p.26 for the final definition of the formal standard. The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem).

HISTORY: New entity in IFC Release 1.0

Attribute definitions

#	Attribute	Type	Cardinality	Description	A
1	DirectionRatios	REAL	L[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)	IfcDimensionCount	[1:1]	The space dimensionality of this class, defined by the number of real in the list of DirectionRatios.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcRepresentationItem
IfcGeometricRepresentationItem
IfcDirection
1	DirectionRatios	REAL	L[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)	IfcDimensionCount	[1:1]	The space dimensionality of this class, defined by the number of real in the list of DirectionRatios.	X

Formal representations

XSD 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="xs:double"/>

       </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 REAL;

 DERIVE

  Dim : IfcDimensionCount := HIINDEX(DirectionRatios);

END_ENTITY;

 EXPRESS-G diagram