Triangle clustering of .stl file

Hello everyone,

I am asking help to the MATLAB community since my head is burning :(

So I have stored two matrices F(mx3) and N(ux3), where u is 3 times m. The first matrix F contains the triangles of an .stl file, namely it containes, in each row, the indices of the rows of matrix N where the X, Y, and Z coordinate are stored. So, for example, if F(1,:) = [1 2 3], it means that the coordinates of the vertices of the first triangle have to be found in rows 1,2, and 3 of matrix N.

Plotting the triangles we have this situation:

Now what i want to do is divide the triangles in different regions (in this case 3, but the number of regions should not be a user input).

I have been able to identify the triangles wich lies on the border writing a small algorithm that search, for each triangle, what are the adjacent triangles (looking for the common edges). All the triangles that only have 1 or 2 adjacent triangles are stored as "Border Triangles".

Here, unfortunately, is where i stop. I have thought to use some graph traversal methods to identify the regions but i am not familiar with this type of techniques.

Any suggestions?

I am not attaching any dataset since it will be to heavy and probably to much confusing.

Hoping to find an answer here :)

Thanks