IfcVector

Definition from ISO/CD 10303-42:1992: The vector is defined in terms of the direction and magnitude of the vector. The value of the magnitude attribute defines the magnitude of the vector.

NOTE: The magnitude of the vector can not be reliable calculated from the components of the Orientation attribute. This form of representation was selected to reduce problems with numerical instability. For example a vector of magnitude 2.0 mm and equally inclined to the coordinate axes could be represented with Orientation attribute of (1.0,1.0,1.0).

NOTE: Corresponding STEP entity: vector. Please refer to ISO/IS 10303-42:1994, p.27 for the final definition of the formal standard. The derived attribute Dim has been added (see also note at IfcGeometricRepresentationItem).

HISTORY: New entity in IFC Release 1.0

EXPRESS specification:

ENTITY IfcVector

SUBTYPE OF (

IfcGeometricRepresentationItem);

Orientation

IfcDirection;

Magnitude

IfcLengthMeasure;

DERIVE

Dim

IfcDimensionCount := Orientation.Dim;

WHERE

WR1

Magnitude >= 0.0;

END_ENTITY;

Attribute definitions:

Orientation	:	The direction of the vector.
Magnitude	:	The magnitude of the vector. All vectors of Magnitude 0.0 are regarded as equal in value regardless of the orientation attribute.
Dim	:	The space dimensionality of this class, it is derived from Orientation

Formal Propositions:

WR1

The magnitude shall be positive or zero.

Inheritance graph

ENTITY IfcVector;

ENTITY IfcRepresentationItem;

INVERSE

LayerAssignments

SET OF IfcPresentationLayerAssignment FOR AssignedItems;

StyledByItem

SET [0:1] OF IfcStyledItem FOR Item;

ENTITY IfcGeometricRepresentationItem;