IfcDirection

IfcDirection

Definition from ISO/CD 10303-42:1992: This entity defines a general direction vector in two or three dimensional space. The actual magnitudes of the components have no effect upon the direction being defined, only the ratios X:Y:Z or X:Y are significant.

NOTE The components of this entity are not normalized. If a unit vector is required it should be normalized before use.

NOTE Corresponding STEP entity: direction. Please refer to ISO/IS 10303-42:1994, p.26 for the final definition of the formal standard. The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem).

HISTORY New class in IFC Release 1.0

EXPRESS specification:

ENTITY IfcDirection

SUBTYPE OF (

IfcGeometricRepresentationItem);

DirectionRatios

LIST [2:3] OF REAL;

DERIVE

Dim

IfcDimensionCount := HIINDEX(DirectionRatios);

END_ENTITY;

Attribute definitions:

DirectionRatios	:	The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3])
Dim	:	The space dimensionality of this class, defined by the number of real in the list of DirectionRatios.