4 Information requirements

This clause specifies the information requirements for the Unstructured mesh application module.

The information requirements are specified as a set of units of functionality, application elements, and application assertions. These assertions pertain to individual application entities and to relationships between application entities. The information requirements are defined using the terminology of the subject area of this application module.

1. - A graphical representation of the information requirements is given in annex C.
2. - The mapping specification is specified in 5.1 which shows how the information requirements are met using the integrated resources of this International Standard. The use of the integrated resources introduces additional requirements which are common to application modules and application protocols.

EXPRESS specification:

*)
SCHEMA Unstructured_mesh_arm;
(*

4.1 Units of functionality

This subclause specifies the units of functionality (UoF) for the Unstructured mesh application module as well as any support elements needed for the module definition. This part of ISO 10303 specifies the following units of functionality:

• Unstructured_mesh.

This part of ISO 10303 uses the following units of functionality:

• Mesh;
• Topology.

The units of functionality and a description of the functions that each UoF supports are given below.

4.1.1 Unstructured_mesh

The Unstructured_mesh UoF specifies:

• the definition of an unstructured mesh as a list of topological regions;
• a list of vertices for an unstructured mesh;
• the order of a vertex defined cell (which determines the number of edge, face and body vertices) and a list of vertices for a vertex defined cell.

NOTE - A structured mesh is defined as a list of topological regions. The boundaries of a topological region can be specified using the entities within ISO 10303-42. The connections between topological regions are defined by their boundaries, so that:

• two edges are connected if they have a common end vertex;
• two faces are connected if they have a common boundary edge; and
• two topological volumes are connected if they have a common boundary face.

The vertices of a topological region can be specified using the entity Vertex_defined_cell. The connections between topological regions can be deduces from their vertices, so that:

• two topological faces are connected along an edge if all the vertices on that edge are common;
• two topological volumes are connected over a face if all the vertices on that face are common.

It is possible to specify either the boundaries for a topological region using the entities in ISO 10303-42, or the vertices for a topological region using the entity Vertex_defined_cell, or both.

The following application objects are used by the Unstructured_mesh UoF:

• Unstructured_mesh;
• Vertex_defined_cell.

4.1.2 Mesh

This UoF is defined in the Mesh module. The following application entities from this UoF are referenced in the Unstructured mesh module:

• Mesh.

4.1.3 Topology

This UoF is defined in the Mesh module. The following application entities from this UoF are referenced in the Unstructured mesh module:

• Region;
• Vertex.

4.2 Required AM ARMs

EXPRESS specification:

*)
USE FROM Mesh_arm -- Mesh
  (Region,
  Mesh,
  Vertex);
(*

4.3 ARM type definitions

• none.

4.4 ARM entity definitions

• Unstructured_mesh
• Vertex_defined_cell

4.5 ARM rule definitions

• none.

4.6 ARM function definitions

• number_of_cell_vertices.

EXPRESS specification:

*)
END_SCHEMA;
(*