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So basically the Forum is now out of date, we are looking into migrating the history.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.

question about convexity

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

question about convexity

Britton Kerin

Does the convexity argument need to be exact (i.e. exact maximum number
of
front/back faces a ray might intersect) or just large enough?  I've
attached
a file that I can't get to display right in preview mode (it comes out
sort
of inside-out), that looks fine when rendered.  I'm guess I have the
wrong
convexity argument or have supplied it in the wrong place.

The file it kind of long but it is mostly just a profile that gets
substituted
in for a rotational extrusion, in form it is like this:

difference (convexity = 1) {
  rotate_extrude (convexity = 10, $fn = 30)
    polygon (@@openscad_poly@@);
  translate ([0, 0, 0.430])
      rotate (0 * 360.0 / 6, [0, 0, 1])
        translate ([0, 2.85, 0])
          cylinder (h = 0.476, r = 0.338 / 2.0, $fn = 10);
}

It also works fine if 'difference' is replaced with 'union'.

Britton



test.scad (23K) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: question about convexity

Philipp Tiefenbacher
try it like this. convexity must be just large enough.

 polygon (@@openscad_poly@@, convexity=10);

Reply | Threaded
Open this post in threaded view
|

Re: question about convexity

Britton Kerin


On Wed, 27 Jan 2010 04:26 +0100, "Philipp Tiefenbacher"
<[hidden email]> wrote:
> try it like this. convexity must be just large enough.
>
>  polygon (@@openscad_poly@@, convexity=10);

No luck.  Even with convexity=10 arguments for every function
(including the for loop, where it seems to do no harm), the same inside-
out effect occurs.

Britton