Extrude 2D Images the way I want to

Hey everybody,

I am currently desperately working on the following - very simple - project: I want to build a "Pi" (=3.14...) shaped piece in order to cut out biscuit dough before baking it.
Simple as that, I made a svg file with Inkscape containing the Pi shape I am looking for. Now, as soon as I import it in OpenSCAD, the lines become filled.

How do I tell openSCAD to use the walls thickness? Of course, I also designed a double lined version which worked out somehow.

How do I realize that project in OpenSCAD the most openscad-ish way? Thus, not just imported via picture but parametric; especially the wallthickness should be parametric. Do you have any ideas?

Thanks so much and bests,
mardy :-)

PS: I attached my svg file just in case.

There are no one dimensional lines in OpenScad, only 2D shapes and 3D solids. Since there is only one boundary to your shape it can only be interpreted as filled in. If you want the shape to be hollow you need to draw the inside boundary as well.

Alternatively you can shell it on OpenScad by doing the Minkowski sum with a small circle or square to expand it and then subtract the original to leave just the expanded outline.

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[www.hydraraptor.blogspot.com]

Thank you!

Could you give me a deeper hint about the second point?

Something like:

module pi() import("pi.dxf");

thickness = 1;

difference() {
    minkowski() {
        pi();
        circle(thickness);
   }
  pi();
}

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[www.hydraraptor.blogspot.com]

Take a look at:

Pi Cookie cutter - and cookie cutter script

Minkowski-ized Tux Cookie Cutter

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
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