Added 3d Gmsh writer function

3d Gmsh ASCII

You can now create and visualize (using Gmsh) an initial domain in 3d, just like you can for 2d. See the Tutorial section which will have a 3d example in the next couple of weeks (or years), similar to the 2d one that illustrates the use of Gmsh.

Significance of 3d Gmsh ASCII

It makes it a lot easier to find node numbers and elements because you can see the initial mesh in 3d and you can therefore see the node and element numbers.

Note

You cannot (yet) use Gmsh to define problems, at this stage Gmsh is used as an aid to find node and element numbers. You still need to define a TPD file. Gmsh is therefore used as a visual aid to define ToPy's TPD files.