Creating Triangulated Surface Mesh Files in ISS Format

ISS (indexed simplex format) is an ASCII file format that can be read by the current Amroc front-end to the Closest-Point-Transform algorithm. The format is simply

[Space dimension of vertices (3 assumed in the following)] [Dimension of simplex elements (2)]
[Number of vertices] 
[Vertex 0: x-coord y-coord z-coord]
[Vertex 1: x-coord y-coord z-coord]
....
[Vertex N-1: x-coord y-coord z-coord]
[Number of triangle connectivities]
[Connection 0: VertexIndex(0,0) VertexIndex(0,1) VertexIndex(0,2)]   
...
[Connection M-1: VertexIndex(M-1,0) VertexIndex(M-1,1) VertexIndex(M-1,2)]   

In the following, ONE possibility is described to create industry-type triangulated surface meshes in ISS format:

1. Get a cost-free academic license for the professional mesher Cubit by Sandia National Laboratories and install it for instance on a Linux machine.
2. Create your 3d model with Cubit and mesh the surfaces you want to export with one of the schemes "TriMesh" or "TriDelaunay".
3. Before you export your mesh, type set default block surface into the Cubit command window.
4. Export the mesh as an Exodus file.
5. Use the tool ncdump that is part of the freely available NetCDF suite by Unidata to convert the binary Exodus file from Cubit into an ASCII file. Syntax: ncdump mesh.exo > mesh.txt
6. Use the conversion script stlib/data/geom/mesh/utilities/exodus2iss32.py to convert the ASCII Exodus file into an ASCII ISS file. Syntax: python stlib/data/geom/mesh/utilities/exodus2iss32.py mesh.txt mesh.iss
7. The directory stlib/examples/geom/mesh= contains some additional tools to work with ISS files.

-- RalfDeiterding - 06 Jun 2006