Foreword

ISO/PDTS 10303-1098 was prepared by Technical Committee ISO/TC 184, Industrial automation systems and integration, Subcommittee SC4, Industrial data.

This International Standard is organized as a series of parts, each published separately. The parts of ISO 10303 fall into one of the following series: description methods, integrated resources, application interpreted constructs, application modules, application protocols, abstract test suites, implementation methods, and conformance testing. The series are described in ISO 10303-1. A complete list of parts of ISO 10303 is available from the Internet:

http://www.nist.gov/sc4/editing/step/titles/.

Annexes A and B form an integral part of this part of ISO 10303. Annexes, C, D, E, aand F are for information only.

Introduction

As unstructured mesh is a mesh that has a irregular arrangement of its cells. Each cell and its connections to adjacent cells is defined separately.

Each cell has a set of vertices with positions determined by the topological shape of the cell and its order. A connection between cells is deduced, if cells have common vertices.

Industrial automation systems and integration —
Product data representation and exchange —
Part 1098: Application module: Unstructured mesh

1 Scope

This application module supports the definition of an unstructured finite element mesh.

The following are within the scope of this application module:

• the cells within a mesh;

  The cells of a mesh are ordered, so that data for the cells can be packed into a single contiguous array.

• the vertices within a mesh;

  The vertices of a mesh are ordered, so that data for the vertices can be packed into a single contiguous array.

• the order for a cell of a mesh, and the vertices consistent with that order.

  The order of a cell specifies the number of edge face and body vertices that are expected. The vertices of a cell are consistent with that order.

  EXAMPLE - The cell shown in Figure 1 has order (2, 2, 1). This cell has a list of 18 vertices.

  Figure 1: A cell with different orders in different directions
  

The following are not within the scope of this application module:

• a finite element model that uses the mesh;
• the definition of a structured mesh by specifying the number of cells in each direction.

  NOTE - A Structured mesh is defined in the structured mesh module.