8.8.3.5 IfcBooleanResult

8.8.3.5.1 Semantic definition

The IfcBooleanResult is the result of applying a Boolean operation to two operands being solids.

NOTE Definition according to ISO/CD 10303-42:1992 A Boolean result is the result of a regularized operation on two solids to create a new solid. Valid operations are regularized union, regularized intersection, and regularized difference. For purpose of Boolean operations, a solid is considered to be a regularized set of points. The final Boolean result depends upon the operation and the two operands. In the case of the difference operator the order of the operands is also significant. The operator can be either union, intersection or difference. The effect of these operators is described below: > * Union on two solids is the new solid that is the regularization of the set of all points that are in either the first operand or the second operand or in both. * Intersection on two solids is the new solid that is the regularization of the set of all points that are in both the first operand and the second operand. * The result of the difference operation on two solids is the regularization of the set of all points which are in the first operand, but not in the second operand.

8.8.3.5.2 Entity inheritance

8.8.3.5.3 Attributes

#	Attribute	Type	Description
IfcRepresentationItem (2)
	LayerAssignment	SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems	Assignment 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.
Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes
IfcBooleanResult (4)
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	IfcDimensionCount	This attribute is formally derived. `FirstOperand.Dim` 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.

Table 8.8.3.5.B

8.8.3.5.4 Formal propositions

Name	Description
FirstOperandClosed	If the FirstOperand is of type IfcTessellatedFaceSet it has to be a closed tessellation.
`NOT('IFC4X3_ADD2.IFCTESSELLATEDFACESET' IN TYPEOF(FirstOperand)) OR (EXISTS(FirstOperand.Closed) AND FirstOperand.Closed)`
SameDim	The dimensionality of the first operand shall be the same as the dimensionality of the second operand.
`FirstOperand.Dim = SecondOperand.Dim`
SecondOperandClosed	If the SecondOperand is of type IfcTessellatedFaceSet it has to be a closed tessellation.
`NOT('IFC4X3_ADD2.IFCTESSELLATEDFACESET' IN TYPEOF(SecondOperand)) OR (EXISTS(SecondOperand.Closed) AND SecondOperand.Closed)`

Table 8.8.3.5.C

8.8.3.5.5 Examples

Figure 8.8.3.5.A

Bath Csg Solid

8.8.3.5.6 Formal representation

ENTITY IfcBooleanResult
 SUPERTYPE OF (ONEOF
	(IfcBooleanClippingResult))
 SUBTYPE OF (IfcGeometricRepresentationItem);
	Operator : IfcBooleanOperator;
	FirstOperand : IfcBooleanOperand;
	SecondOperand : IfcBooleanOperand;
 DERIVE
	 Dim : IfcDimensionCount := FirstOperand.Dim;
 WHERE
	FirstOperandClosed : NOT('IFC4X3_ADD2.IFCTESSELLATEDFACESET' IN TYPEOF(FirstOperand)) OR (EXISTS(FirstOperand.Closed) AND FirstOperand.Closed);
	SameDim : FirstOperand.Dim = SecondOperand.Dim;
	SecondOperandClosed : NOT('IFC4X3_ADD2.IFCTESSELLATEDFACESET' IN TYPEOF(SecondOperand)) OR (EXISTS(SecondOperand.Closed) AND SecondOperand.Closed);
END_ENTITY;