Definition from ISO/CD 10303-42:1992: This select type identifies
all those types of entities which may participate in a Boolean operation to
form a CSG solid.
Definition from IAI: CSG primitives are out of scope for the
current IFC Release. Only faceted B-reps, swept area solids and half space
solids are available as Boolean operands. Boolean result themselves can be used
as operands thus enabling nested Boolean operations.
NOTE Corresponding STEP type:
boolean_operand, please refer to ISO/IS 10303-42:1994, p.167 for the final
definition of the formal standard. In IFC Release 1.5.1 & 2.0 only Boolean
results (IfcBooleanResult), half space solids
(IfcHalfSpaceSolid), faceted B-Rep, extruded solids and revolved solids
(IfcSolidModel) are defined for being valid Boolean operands.
HISTORY: New Type in IFC Release 1.5.1
