Re: [rp-ml] Automatic stl file validation and volume estimation

From: Wesley Brooks (wesbrooks@gmail.com)
Date: Mon Feb 19 2007 - 11:45:40 EET


Have you got any programming experience? If so have a look at the VTK
toolkit from Kitware. This is an open source project with a lot of
tools for manipulating triangular mesh format objects.

I would suggest the following;

1* Read an STL file into a vtkPolyData object,
2* Clean up the polydata object (required as STL format does not
recored shared points),
3* Write (or check to see if the following exists) a small method to
seach through the whole mesh to ensure that no line is repeated in the
file,
4* Write (or check to see if the following exists) a small method to
seach through each triangle to ensure that each pair of points on an
edge are shared (but reversed) with an edge on another triangle.

This would check is the surface has no flipped triangles (step 3, line
with points 1-2 does not equal a line with points 2-1), and that the
surface has no gaps (step 4, if there was a gap then some triangles
would not share an edge with another). However, this would not
discover an inverted surface, and this would also have difficulties
with overlapping triangles in the same plane pointing in oposing
directions. This said it's a start for you!

Cheers,

Wes.

On 19/02/07, John McNeil <john@mcneilco.com> wrote:
> All,
>
> Do you know of software that can be used to automatically check STL
> file validity for printing? I need to run it from the command line,
> ideally on *nix and ideally open source (but I'd pay if I have to).
> For example, what do the on-line print services like RedEye use on
> their web sites? I am printing FDM with a Dimension SST 1200 if that
> matters.
>
> John
>
>



This archive was generated by hypermail 2.1.7 : Tue Jan 01 2008 - 18:13:02 EET