4 Information requirements

This clause specifies the information requirements for the Constructive solid geometry 3D application module. The information requirements are specified as the Application Reference Model (ARM) of this application module.

NOTE 1  A graphical representation of the information requirements is given in Annex C.

NOTE 2  The mapping specification is specified in 5.1. It shows how the information requirements are met by using common resources and constructs defined or imported in the MIM schema of this application module.

This clause defines the information requirements to which implementations shall conform using the EXPRESS language as defined in ISO 10303-11. The following begins the Constructive_solid_geometry_3d_arm schema and identifies the necessary external references.

4.1 Required AM ARMs

The following EXPRESS interface statements specify the elements imported from the ARMs of other application modules.

EXPRESS specification:

*)
USE FROM Elemental_geometric_shape_arm;    --  ISO/TS 10303-1004



USE FROM Primitive_solids_arm;    --  ISO/TS 10303-1791
(*



NOTE 1   The schemas referenced above are specified in the following part of ISO 10303:

Elemental_geometric_shape_arm	ISO/TS 10303-1004
Primitive_solids_arm	ISO/TS 10303-1791

NOTE 2   See Annex C, Figures C.1and C.2 for a graphical representation of this schema.

4.2 ARM entity definition

This subclause specifies the ARM entity for this module. The ARM entity is an atomic element that embodies a unique application concept and contains attributes specifying the data elements of the entity. The ARM entity and definition is specified below.

4.2.1 Csg_model   

A Csg_model is a type of Geometric_model defined by a collection of primitive solids, combined using regularised boolean operations. The allowed operations are intersection, union, and difference.

NOTE 1   This entity is incompletely modelled in the ARM. Complete specification can be obtained in the definition of the corresponding MIM entity.

NOTE 2   As a special case, a Csg_model can also include a single CSG primitive, as defined in Primitive solids.

NOTE 3   A regularised subset of space is the closure of its interior, in the usual sense of point set topology. For boolean results, regularisation has the effect of removing dangling edges and other anomalies produced by the original operations.

EXPRESS specification:

*)
ENTITY Csg_model
  SUBTYPE OF (Geometric_model);
END_ENTITY;
(*

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