IFC 4.3.x development

8.9.3.1 IfcAxis1Placement

Change log

IFC4

additionswhere_rulesAxisIs3D
additionswhere_rulesLocationIs3D
deletionswhere_rulesWR1
deletionswhere_rulesWR2

IFC4X3_RC3

additionswhere_rulesLocationIsCP

8.9.3.1.1 Semantic definitions at the entity

The IfcAxis1Placement provides location and direction of a single axis.

axis1 placement
Figure 1 illustrates the definition of the IfcAxis1Placement within the parent three-dimensional coordinate system.

Figure 1 — 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

8.9.3.1.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item 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.
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.
Dim INVALID The space dimensionality of this class, derived from the dimensionality of the location.
IfcAxis1Placement
2 Axis OPTIONAL IfcDirection The direction of the local Z axis.
Z INVALID 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.]

8.9.3.1.2 Entity inheritance

dot_inheritance IfcAxis1Placement IfcAxis1Placement IfcPlacement IfcPlacement IfcAxis1Placement->IfcPlacement IfcPlacement_children 3 more... IfcPlacement_children->IfcPlacement IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcPlacement->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.1.3 Formal representations

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 : 'IFC4X3_DEV.IFCCARTESIANPOINT' IN TYPEOF(SELF\IfcPlacement.Location);
END_ENTITY;