Region Application Object

A Region is a Topological_object that is a continuous point set that has a single topological dimension.

EXPRESS specification:

*)
ENTITY Region
  SUBTYPE OF (Topological_object);
  topological_dimension :  INTEGER;
  shape :  OPTIONAL Topological_shape;
  DERIVE
    standard_shape :  BOOLEAN =: IF EXISTS (shape) THEN
                                   shape.supplier = '10303';
                                 ELSE
                                   FALSE;
                                 ENDIF;        
    shape_code :  STRING =: IF EXISTS (shape) THEN
                              shape.code;
                            ELSE
                              '';
                            ENDIF;      
  WHERE
    valid_dimension :  topological_dimension > 1;
    valid_shape : 
      IF standard_shape THEN 
        CASE dimension OF
          1 : shape_code IN ['TS001'];
          2 : shape_code IN ['TS002', 'TS003'];
          3 : shape_code IN ['TS004', 'TS005', 'TS006', 'TS007'}; 
          OTHERWISE : FALSE;
        END_CASE;
      ELSE 
        TRUE;
      END_IF;  
END_ENTITY;
(*

Attribute definitions:

topological_dimension: The dimension of a real tuple space for which a 1-1 mapping exists between:

• the members of a set that is classified as a region; and
• the values within a real tuple space.

The set of points within widget type XYZ_123 is classified as being a 3D topological object. This means that there is a 1-1 mapping between points within widget type XYZ_123 and a space of real triples.

shape: The shape of the region, which indicates the number of edges or faces, as follows:

triangle

a 2D region with three edges;

quadrilateral

a 2D region with four edges;

tetrahedron

a 3D region with four triangular faces;

pyramid

a 3D region with four triangular faces and one quadrilateral face;

wedge

a 3D region with three quadrilateral and two triangular faces;

hexahedron

a 3D region with six quadrilateral faces.

A Region can have a shape which is none of the above.

standard_shape: A Boolean flag that is:

true:

the shape is specified, and is a standard shape defined by this part of ISO 10303;

false:

otherwise.

shape_code: A text string that is:

• the shape code, if the shape is specified and a standard shape defined by this part of ISO 10303;
• null, otherwise.

Formation propositions:

valid_dimension: A Region shall have a topological dimension greater than 0, i.e. it shall not be a vertex.

valid_shape: If a Region has a standard shape, then the shape shall be consistent with the topological dimension.