IfcAxis1Placement

Semantic definitions at the entity

Entity definition

The IfcAxis1Placement provides location and direction of a single axis.

	Figure 336 illustrates the definition of the IfcAxis1Placement within the parent three-dimensional coordinate system.
Figure 336 — 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	C
2	Axis	IfcDirection	[0:1]	The direction of the local Z axis.	X
	Z :=NVL (IfcNormalise(Axis), IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcDirection([0.0,0.0,1.0]))	IfcDirection	[1:1]	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.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
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.	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.	X
IfcGeometricRepresentationItem
IfcPlacement
1	Location	IfcCartesianPoint	[1:1]	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	[1:1]	The space dimensionality of this class, derived from the dimensionality of the location.	X
IfcAxis1Placement
2	Axis	IfcDirection	[0:1]	The direction of the local Z axis.	X
	Z :=NVL (IfcNormalise(Axis), IfcRepresentationItem() \|\| IfcGeometricRepresentationItem () \|\| IfcDirection([0.0,0.0,1.0]))	IfcDirection	[1:1]	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

XSD 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;
END_ENTITY;

 EXPRESS-G diagram

	Einfügepunkt mit einer Achse
	Axis1 Placement
	Position et direction d'un axe