stl export bug report/pyopenscad

hi!

I'm playing around with generating scad code...and generated this
level 3 sierpinsky triangle. when I try to export it openscad writes:

Object isn't a single polyhedron or otherwise invalid! Modify your design..

I know the normal sierpinski triangle isn't a single polyhedron, but
this one has a base plate so it should

I also attached the python code that generated the openscad
code...once it works I'd like to add these scripts to the openscad
examples

openscad is cool!

greetings
wizard23


--
:: Philipp Tiefenbacher
:: custom electronics/magic
:: http://www.wizards23.net

Any sufficiently advanced technology is indistinguishable from magic
--Arthur C. Clarke

Hi Philipp,

On Thu, Dec 03, 2009 at 04:13:57AM +0100, Philipp Tiefenbacher wrote:
> I'm playing around with generating scad code...and generated this
> level 3 sierpinsky triangle. when I try to export it openscad writes:
>
> Object isn't a single polyhedron or otherwise invalid! Modify your design..

sorry for the delay.

the error message is missleading and I have changed it now to:

        Object isn't a valid 2-manifold! Modify your design..

because that is what happens here.

a description of the problem can be found here:
http://rocklinux.net/pipermail/openscad/2009-December/000018.html

in a valid 2-manifold each edge must connect extactly two facets. in your
sierpinsky triangle the edges of the extruded triangles touch each other so
the edge now connects four facets. one possible solution would be to
enlarge the triangles a little bit so they become intersecting.

yours,
 - clifford

--
"In the future, airplanes will be flown by a dog and a pilot. And the
dog's job will be to make sure that if the pilot tries to touch any of
the buttons, the dog bites him." - Scott Adams (author of Dilbert).