IfcAxis1Placement

Item	SPF	XML	Change	Description
IFC4x3_RC1 to IFC4x3_RC2
IfcAxis1Placement
Location	X	X	MODIFIED	Type changed from IfcCartesianPoint to IfcPoint.

Semantic definitions at the entity

Entity definition

The IfcAxis1Placement provides location and direction of a single axis.

	Figure 512 illustrates the definition of the IfcAxis1Placement within the parent three-dimensional coordinate system.
Figure 512 — Axis1 placement

NOTE Definition according to ISO/CD 10303-42:1992
The direction and location in three dimensional space of a single axis. An axis1_placement is defined in terms of a locating point (inherited from placement supertype) and an axis direction: this is either the direction of axis or defaults to (0.0,0.0,1.0). The actual direction for the axis placement is given by the derived attribute z.

NOTE Entity adapted from axis1_placement defined in ISO10303-42.

HISTORY New entity in IFC1.5

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
2	Axis	IfcDirection	?	The direction of the local Z axis.	X
	Z :=NVL (IfcNormalise(Axis), IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcDirection([0.0,0.0,1.0]))	IfcDirection		The normalized direction of the local Z axis. It is either identical with the Axis value, if given, or it defaults to [0.,0.,1.]	X

Formal Propositions

Rule	Description
AxisIs3D	The Axis when given should only reference a three-dimensional IfcDirection.
LocationIs3D	The Cartesian point defining the Location shall have the dimensionality of 3.
LocationIsCP

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
IfcPlacement
1	Location	IfcPoint		The geometric position of a reference point, such as the center of a circle, of the item to be located.	X
	Dim :=Location.Dim	IfcDimensionCount		The space dimensionality of this class, derived from the dimensionality of the location.	X
IfcAxis1Placement
2	Axis	IfcDirection	?	The direction of the local Z axis.	X
	Z :=NVL (IfcNormalise(Axis), IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcDirection([0.0,0.0,1.0]))	IfcDirection		The normalized direction of the local Z axis. It is either identical with the Axis value, if given, or it defaults to [0.,0.,1.]	X

Formal representations

XML Specification

 <xs:element name="IfcAxis1Placement" type="ifc:IfcAxis1Placement" substitutionGroup="ifc:IfcPlacement" nillable="true"/>

 <xs:complexType name="IfcAxis1Placement">

  <xs:complexContent>

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

    <xs:sequence>

     <xs:element name="Axis" type="ifc:IfcDirection" nillable="true" minOccurs="0"/>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcAxis1Placement

 SUBTYPE OF (IfcPlacement);

  Axis : OPTIONAL IfcDirection;

 DERIVE

  Z : IfcDirection := NVL (IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]));

 WHERE

  AxisIs3D : (NOT (EXISTS (Axis))) OR (Axis.Dim = 3);
  LocationIs3D : SELF\IfcPlacement.Location.Dim = 3;
  LocationIsCP : 'IFCGEOMETRYRESOURCE.IfcCartesianPoint' IN TYPEOF(SELF\IfcPlacement.Location);
END_ENTITY;

 EXPRESS-G diagram

	Einfügepunkt mit einer Achse
	Axis 1 Placement
	Position et direction d'un axe