Nabble has removed Mailing-list integration.
Posts created here DO NOT GET SENT TO THE MAILING LIST.
Mailing-list emails DO NOT GET POSTED TO THE FORUM.
So basically the Forum is now out of date, we are looking into migrating the history.

For now you should send emails, people will see them, discuss@lists.openscad.org.

Re: Importing STLs with multiple volumes/shells in OpenSCAD

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

Re: Importing STLs with multiple volumes/shells in OpenSCAD

Clifford Wolf
Hi Jonas,

I'm sending this mail CC to the openscad mailing list.

On Wed, Dec 30, 2009 at 08:20:48PM +0100, Jonas Pfeil wrote:
> I tested with example 12, which worked and then modified the STL file to
> contain a second identical mesh next to the original one. This resulted in
> a crash. The CGAL example program for 3D Nef polyhedra also crashed on me
> when I investigated CGAL a few months ago. Is it possible to use CGAL (or
> OpenSCAD) for meshes that have multiple shells/volumes (e.g. two boxes that
> do not intersect)? There probably exists a mathematical term for this ;)

yes. this is possible.

e.g. I can render the following openscad script to an stl file:

        translate([ -60, 0, 0 ]) cube(100, true);
        translate([ +60, 0, 0 ]) cube(100, true);

And I can use this stl file in another design without any problems:

        import_stl(filename = "demo.stl");

However, when the stl file is not 100% valid you have a good chance of
crashing CGAL. An invalid STL file would of course be everything that is not a
valid 2-manifold like (1) self intersecting structures (2) structures
where a half edge does not have extacly one matching other half edge with
the same vetrices but in the other order or (3) infinite objects.

yours,
 - clifford

--
Caffeine for mind, pizza for body, sushi for soul.

Reply | Threaded
Open this post in threaded view
|

Re: Importing STLs with multiple volumes/shells in OpenSCAD

Clifford Wolf
Hi Jonas, hi list,

On Sun, Jan 03, 2010 at 02:48:25AM +0100, Jonas Pfeil wrote:
> I'm quite positive, that my file is ok. I just duplicated the mesh from
> example 12 in blender. The meshes are not touching. I also checked the STL
> file in netfabb. I attached the file I used in case you want to test it. It
> crashes when just importing the STL after pressing F6.

got it:

there was a bug in the loader for binary stl files. It is fixed now in svn
rev 196. I've added the binary STL file you created as part of testcase
examples/example016.scad.

yours,
 - clifford

--
/"\  ASCII Ribbon Campaign - against html email
\ /                        - against microsoft office attachments
 X                         - against text above fullquote below
/ \                        - against lines longer than 79 characters