IfcAxis1Placement

Natural language names
Einfügepunkt mit einer Achse
Axis 1 Placement
Position et direction d'un axe
Change log
ItemSPFXMLChangeDescription
IFC4x3_RC1 to IFC4x3_RC2
    IfcAxis1Placement
      LocationXXMODIFIEDType changed from IfcCartesianPoint to IfcPoint.
Semantic definitions at the entity
Entity definition

The IfcAxis1Placement provides location and direction of a single axis.

axis1 placement
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
#AttributeTypeCardinalityDescription G
2AxisIfcDirection? The direction of the local Z axis. X
Z
:=NVL (IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]))
IfcDirectionThe 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
RuleDescription
AxisIs3DThe Axis when given should only reference a three-dimensional IfcDirection.
LocationIs3DThe Cartesian point defining the Location shall have the dimensionality of 3.
LocationIsCP
Inherited definitions from supertypes
Entity inheritance IfcPlacement 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
IfcPlacement
1LocationIfcPoint The geometric position of a reference point, such as the center of a circle, of the item to be located. X
Dim
:=Location.Dim
IfcDimensionCountThe space dimensionality of this class, derived from the dimensionality of the location. X
IfcAxis1Placement
2AxisIfcDirection? The direction of the local Z axis. X
Z
:=NVL (IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]))
IfcDirectionThe 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;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcRevolvedAreaSolid IfcSurfaceOfRevolution

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