IfcLine

Definition from ISO/CD 10303-42:1992: A line is an unbounded curve with constant tangent direction. A line is defined by a point and a direction. The positive direction of the line is in the direction of the Dir vector. The line is parameterized as follows:

P = Pnt
V = Dir
l(u) = P + uV

and the parametric range is -¥ < u < ¥

NOTE Corresponding STEP entity: line. Please refer to ISO/IS 10303-42:1994, p.37 for the final definition of the formal standard. The derived attribute Dim has been added at this level and was therefore demoted from the geometric_representation_item.

HISTORY New class in IFC Release 1.0

EXPRESS specification:

ENTITY IfcLine

SUBTYPE OF (

IfcCurve);

Pnt

IfcCartesianPoint;

Dir

IfcVector;

WHERE

WR1

Dir.Dim = Pnt.Dim;

END_ENTITY;

Attribute definitions:

Pnt	:	The location of the line.
Dir	:	The direction of the line, the magnitude and units of Dir affect the parameterization of the line.

Formal Propositions:

WR1

The dimensionality of the location (IfcCartesianPoint) shall be the same as of the direction (IfcVector).

Inheritance graph

ENTITY IfcLine;

ENTITY IfcRepresentationItem;

INVERSE

LayerAssignments

SET OF IfcPresentationLayerAssignment FOR AssignedItems;

StyledByItem

SET [0:1] OF IfcStyledItem FOR Item;

ENTITY IfcGeometricRepresentationItem;

ENTITY IfcCurve;

DERIVE

Dim

IfcDimensionCount := IfcCurveDim(SELF);

ENTITY IfcLine;

Pnt

IfcCartesianPoint;

Dir

IfcVector;

END_ENTITY;