Require to:

• plot 2d rectangular bounding boxes that encompass all steps in the tracking output with a particular volume name; label with volume name and material
• plot 1d on-axis volume map; Label with volume name
• look at differences between two geometries (not quite sure yet how best to do this, will think)

I implemented the plots as per request, sample output (from integration test) is attached. Note that in the 1D plot, two lines are apparent - the grey line is the volume extent in z at all points, the black line is the volume extent in z on-axis. For the 2D plot, note the coloured rectangles are "bounding boxes" in z and r, i.e. I calculate the smallest possible rectangle that can encompass all points and plot this. Doing a "convex hull" or similar is quite difficult and beyond the scope of this feature.

For the "diff"ing of two geometries, I made a volume bounding box json output file. User then has to manually inspect the output file for differences (well more likely they would make a script). This works as long as the CAD import has stable volume names for this version or that version. I attach a sample output, format is something like:

{
  <string volume name>: {
    "z_min": <float minimum z of steps in volume>,
    "z_max": <float maximum z of steps in volume>, 
    "r_min": <float minimum radius of steps in volume>,
    "r_max": <float maximum radius of steps in volume>, 
    "material": <string material name>
  }, 
  ...
}

e.g.

  "Vol14": {
    "z_max": 320.0, 
    "r_min": 0.0, 
    "material": "G4_Al", 
    "r_max": 2.23606806280132, 
    "z_min": 280.0
  }, 
  ...

I will run it through test and if it goes smoothly commit later today.