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8.9.3.4 IfcAxis2PlacementLinear

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8.9.3.4.1 Semantic definition

The IfcAxis2PlacementLinear provides location and orientation to place items in a three-dimensional space confined to the context of a curve. Relative placement axes (Axis and RefDirection) are relative to the curve used for linear referencing provided in IfcPlacement Location (IfcPointByDistanceExpression BasisCurve), maintaining the relationship to the tangent of the curve.

8.9.3.4.2 Entity inheritance

8.9.3.4.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
IfcPlacement (2)
Click to show 4 hidden inherited attributes
IfcAxis2PlacementLinear (2)
2 Axis OPTIONAL IfcDirection

The exact direction of the local Z Axis.

3 RefDirection OPTIONAL IfcDirection

The direction used to determine the direction of the local X Axis. In case both Axis and RefDirection are set and not perpendicular an adjustment is necessary to maintain orthogonality to the Axis direction. If RefDirection is omitted, the direction is taken from the curve tangent at Location.

Table 8.9.3.4.C

8.9.3.4.4 Formal propositions

Name Description
WR1

The Location on parent type IfcPlacement shall be of type IfcPointByDistanceExpression

'IFC4X3_DEV_738df036.IFCPOINTBYDISTANCEEXPRESSION' IN TYPEOF(SELF\IfcPlacement.Location)
WR2

The Axis and RefDirection shall not be parallel or anti-parallel.

(NOT (EXISTS (Axis))) OR (NOT (EXISTS (RefDirection))) OR (IfcCrossProduct(Axis,RefDirection).Magnitude > 0.0)
Table 8.9.3.4.D

8.9.3.4.5 Examples

8.9.3.4.6 Formal representation

ENTITY IfcAxis2PlacementLinear
SUBTYPE OF (IfcPlacement);
Axis : OPTIONAL IfcDirection;
RefDirection : OPTIONAL IfcDirection;
WHERE
WR1 : 'IFC4X3_DEV_738df036.IFCPOINTBYDISTANCEEXPRESSION' IN TYPEOF(SELF\IfcPlacement.Location);
WR2 : (NOT (EXISTS (Axis))) OR (NOT (EXISTS (RefDirection))) OR (IfcCrossProduct(Axis,RefDirection).Magnitude > 0.0);
END_ENTITY;

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3 contributor(s):
Last change: Improve definition split (#876) * bring back headers headers were previously removed by mistake, now bringing them back * add new lines and rename the tag add the word 'short' in it * unify newlines make exactly one newline before and two after the tag * resolving typos Because bringing back headers required to go back in time to previous version, I'm now re-resolving the issues: #861, #860, #856 by ArturTomczak on 7/16/2024, 2:07:28 PM

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8.9.3.4.7 Changelog

8.9.3.4.7.1 IFC4.3_DEV_738df036

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