CONSTRUCT—SCOPE—ENTITY

ENTITY CONSTRUCT SCOPE ENTITY = CLASS( P0INT(D3),EDGE CURVE,... 

A CONSTRUCT is an entity that has a scope. The data structure of a construct represents a three-dimensional geometrical shape. Certain domains of this shape may have material properties associated with them. A construct is not an elementary solid model but defines a function which -when evaluated- will produce a solid. The function operators are BOOLEAN, the operands are of type BOOL OPERAND. The elementary operands which are called PRIMITIVE entities exist in the scope of the CONSTRUCT only. However, POLYHEDRON models and B REP entities may exist in the construct scope and may be used as operands to boolean operations (if the CAD system provides this capability). The attribute result is an instance of the BOOLEAN which represents the root of the boolean tree or simply of a PRIMITIVE, B REP, POLYHEDRON, or another CONSTRUCT. 

This is a class of entities that can exist only in the scope of a CONSTRUCT entity. They are used as operands in boolean expressions. The attribute list of a PRIMITIVE entity consists of... 

The HYBRID SOLID entity corresponds in the field of solids to what the REAL and INTEGER entities are in the field of arithmetics. A hybrid solid consists of a functional description of a solids model in the form of a CONSTRUCT (referenced by the attribute expression) and its evaluated value in the form of a list of B REP models (referenced by the attribute value). Both the value and the expression must refer to entities that are inside the scope of the hybrid solid. 

On this level, no entities of type CONSTRUCT are available. Also, entities which can occur only within the scope of CONSTRUCT entities (such as BOX) are not available. 

CONSTRUCT OPEN, HYBRID SOLID OPEN, LINEAR SWEEP OPEN,. . and so on for all entities with scope... READY FOR INTERPRETATION, UNDEFINED ) ... 

---