Measuring geometric values from a CAD-generated .stl mesh file

Hi all,

I have been working on some model meshes I made in Blender and import into MATLAB in the .stl file format, retaining their connectivity between vertices and face information. One thing I'd like to do is measure the radius of curvature at the tips of these models, which seems to be quite imprecise in Blender, but seems like a task MATLAB could handle.

In the image attached is the geometric form a basic bipyramid will take on; here I am looking to calculate the radius of curvature (r). If it would be straightforward to do, calculating the h and R would also be of great interest!

I think my main concern if finding some centroid inside of the tip to then calculate r, not sure how to do that? This is also more of a geometry issue, but I also don't see a clear way to determine where the tip ends and the rest of the bipyramid begins?

I have found this helpful set of code in the exchange that could be useful, but it only allows input of three points for determining curvature, so I'm unsure how I could implement its use for my problem. https://www.mathworks.com/matlabcentral/fileexchange/69452-curvature-of-a-1d-curve-in-a-2d-or-3d-space

I have attached an example .stl file as well, feel free to use this in your answer, here at this dropbox link. TIA!!

[Iosif Papadakis Ktistakis]

@Caitlin Did you figure out the answer to your problem?