I am trying to create an unstructured grid from a set of points loaded from csv file. The points come form Anys Fluent simulation. For a very basic case I consider only a simple 2D rectangle where I calculate only heat conduction. In the file I have around 1000 points (x,y coordinates + temperature at point/node).
I have managed to read those data to Paraview (using C++ examples on vtk webside) with the use of polydata object nd Delaunay2D triangulation. I have checked my code also for some more complicated geometries and I have noticed that with Delaunay2D you have to control Alpha parameter to avoid incorrect connection of the points. I have also checked the code for the case of air flow in 2D channel and it gave more or less OK results in Paraview, however in the boundary layer when I have a lot of thin and long elements in Fluent mesh, the reproduction with Delaunay2D in Paraview is I would say not bad but I think that with unstructured mesh I could have a better result.
Unfortunately, what I have noticed in case of an unstructured meshes, If you want to create it form scratch and build it for example from quad elements you have to take care on the nodes numbering and correct connectivity. Otherwise you will obtain horrible results (or even no vtu file will be created).
With unstructred mesh I was able to visualize only 2 elements what allowed me to get to the above conclusion. Now is the time for my question:
I don’t see a possibility to track a connectivity and numbering of hundred thousands of points (maybe I am wrong), so could you help me understand how I can create (with c++) an unstructured mesh from let’ say randomly distributed points. Is it possible?
Thanks in advance.