STL File Validation

Question

I have an ASCII stl file and I need to validate this file for the 3D printer by the following criteria.

First I would like to show the structure of the file:

facet normal ni nj nk
    outer loop
        vertex v1x v1y v1z
        vertex v2x v2y v2z
        vertex v3x v3y v3z
    endloop
endfacet

There are more facets(triangles) in the ASCII stl file in the above format. The three vertex represents three point in 3D which create a 2D triangle. In practice, however, all facets are simple triangles. These triangles create one or more shell object(a simple 3D object).

What I need, is check the number of shell. In other words, I would like to count that how many separated objects were created with these triangles.

I upload my stl file on MakePrintable online stl file repair software and I got the following details from my file: Triangle Count x 3 = Vertex Count (three vertex (3D points) creates one triangle, like I wrote)

So, I think it's possible to count the shell's number, but I don't how and this software is not open source (so I also can't copy the shell counter logic from here :) ). If anyone could help me, please leave me an answer.

Answer 1

Open your file in Meshlab and unify the duplicate vertices. Then go to

Filters > Quality Measure and Computation > Compute Topological Measures

You can read the number of connected components in the window on the bottom right of your screen.

Alternatively, you can count the vertices, edges and faces and use Euler's formula.