IFC 4.3.x development

8.8.3.4 IfcBooleanClippingResult

Change log

IFC4

additionswhere_rulesFirstOperandType
additionswhere_rulesOperatorType
additionswhere_rulesSecondOperandType
deletionswhere_rulesWR1
deletionswhere_rulesWR2
deletionswhere_rulesWR3

IFC4X1

additionswhere_rulesFirstOperandType
additionswhere_rulesSecondOperandType
deletionswhere_rulesFirstOperandType
deletionswhere_rulesSecondOperandType

IFC4X2

additionswhere_rulesFirstOperandType
additionswhere_rulesSecondOperandType
deletionswhere_rulesFirstOperandType
deletionswhere_rulesSecondOperandType

IFC4X3_RC3

additionswhere_rulesFirstOperandType
additionswhere_rulesSecondOperandType
deletionswhere_rulesFirstOperandType
deletionswhere_rulesSecondOperandType

8.8.3.4.1 Semantic definitions at the entity

A clipping result is defined as a special subtype of the general IfcBooleanResult. It constrains the operands and the operator of the Boolean result.

A clipping result is the Boolean difference between a swept solid and a half space solid, or between the result of the Boolean difference and a half space solid. Hence more than one difference operation can be applied to achieve the final Boolean result.

HISTORY  New entity in IFC2x.

Formal Propositions

FirstOperandType

The first operand of the Boolean clipping operation shall be either an IfcSweptAreaSolid or (in case of more than one clipping) an IfcBooleanResult.

SecondOperandType

The second operand of the Boolean clipping operation shall be an IfcHalfSpaceSolid.

OperatorType

The Boolean operator for clipping is always "Difference".

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

> IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcBooleanResult
1 Operator IfcBooleanOperator The Boolean operator used in the operation to create the result.
2 FirstOperand IfcBooleanOperand The first operand to be operated upon by the Boolean operation.
3 SecondOperand IfcBooleanOperand The second operand specified for the operation.
Dim INVALID The space dimensionality of this entity. It is identical with the space dimensionality of the first operand. A where rule ensures that both operands have the same space dimensionality.

8.8.3.4.1 Entity inheritance

dot_inheritance IfcBooleanClippingResult IfcBooleanClippingResult IfcBooleanResult IfcBooleanResult IfcBooleanClippingResult->IfcBooleanResult IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcBooleanResult->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.8.3.4.2 Formal representations

ENTITY IfcBooleanClippingResult
 SUBTYPE OF (IfcBooleanResult);
 WHERE
	FirstOperandType : ('IFC4X3_DEV_a1492713.IFCSWEPTAREASOLID' IN TYPEOF(FirstOperand)) OR 
('IFC4X3_DEV_a1492713.IFCSWEPTDISCSOLID' IN TYPEOF(FirstOperand)) OR 
('IFC4X3_DEV_a1492713.IFCBOOLEANCLIPPINGRESULT' IN TYPEOF(FirstOperand));
	SecondOperandType : ('IFC4X3_DEV_a1492713.IFCHALFSPACESOLID' IN TYPEOF(SecondOperand));
	OperatorType : Operator = DIFFERENCE;
END_ENTITY;