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IfcGeometricRepresentationSubContext

Definition from IAI: The IfcGeometricRepresentationSubContext defines the context that applies to several shape representations of a product as being a sub context, sharing the WorldCoordinateSystem, CoordinateSpaceDimension, Precision and TrueNorth attributes with the parent IfcGeometricRepresentationContext.

The IfcGeometricRepresentationSubContext is used define semantically distinguished representation types for different information content, dependent on the representation view and the target scale. It can be used to control the level of detail of the shape representation that is most applicable to this geometric representation context.

Each IfcProduct can then have several IfcShapeRepresentation's, each being assigned to a different geometric representation type (IfcGeometricRepresentationContext or IfcGeometricRepresentationSubContext). The application can then choose the most appropriate representation for showing the geometric shape of the product.

HISTORY: New entity in Release IFC 2x Edition 2.

EXPRESS specification:

ENTITY IfcGeometricRepresentationSubContext
SUBTYPE OF ( IfcGeometricRepresentationContext);
ParentContext  :  IfcGeometricRepresentationContext;
TargetScale  :  OPTIONAL IfcPositiveRatioMeasure;
TargetView  :  IfcGeometricProjectionEnum;
UserDefinedTargetView  :  OPTIONAL IfcLabel;
DERIVE
SELF\IfcGeometricRepresentationContext.WorldCoordinateSystem  :  IfcAxis2Placement :=  ParentContext.WorldCoordinateSystem;
SELF\IfcGeometricRepresentationContext.CoordinateSpaceDimension  :  IfcDimensionCount :=  ParentContext.CoordinateSpaceDimension;
SELF\IfcGeometricRepresentationContext.TrueNorth  :  IfcDirection :=  ParentContext.TrueNorth;
SELF\IfcGeometricRepresentationContext.Precision  :  REAL :=  ParentContext.Precision;
WHERE
WR31  :  NOT('IFCREPRESENTATIONRESOURCE.IFCGEOMETRICREPRESENTATIONSUBCONTEXT' IN TYPEOF(ParentContext));
WR32  :  (TargetView <> IfcGeometricProjectionEnum.USERDEFINED) OR ((TargetView = IfcGeometricProjectionEnum.USERDEFINED) AND EXISTS(UserDefinedTargetView)) ;
END_ENTITY;

Attribute definitions:

ParentContext  :  Parent context from which the sub context derives its world coordinate system, precision, space coordinate dimension and true north.
TargetScale  :  The target scale of the representation to which this representation context applies.
TargetView  :  Target view of the representation to which this representation context applies.
UserDefinedTargetView  :  User defined target view, this attribute value shall be given, if the TargetView attribute is set to USERDEFINED.

Formal Propositions:

WR31  :  The parent context shall not be another geometric representation sub context.
WR32  :  The attribute UserDefinedTargetView shall be given, if the attribute TargetView is set to USERDEFINED.

Inheritance graph

ENTITY IfcGeometricRepresentationSubContext;
ENTITY IfcRepresentationContext;
ContextIdentifier  :  OPTIONAL IfcLabel;
ContextType  :  OPTIONAL IfcLabel;
INVERSE
RepresentationsInContext  :  SET OF IfcRepresentation FOR ContextOfItems;
ENTITY IfcGeometricRepresentationContext;
ENTITY IfcGeometricRepresentationSubContext;
ParentContext  :  IfcGeometricRepresentationContext;
TargetScale  :  OPTIONAL IfcPositiveRatioMeasure;
TargetView  :  IfcGeometricProjectionEnum;
UserDefinedTargetView  :  OPTIONAL IfcLabel;
DERIVE
WorldCoordinateSystem  :  IfcAxis2Placement :=  ParentContext.WorldCoordinateSystem;
SELF\IfcGeometricRepresentationContext.CoordinateSpaceDimension  :  IfcDimensionCount :=  ParentContext.CoordinateSpaceDimension;
SELF\IfcGeometricRepresentationContext.TrueNorth  :  IfcDirection :=  ParentContext.TrueNorth;
SELF\IfcGeometricRepresentationContext.Precision  :  REAL :=  ParentContext.Precision;
END_ENTITY;