Let's look at a simple example using OpenSCAD. A rectangular plate with screw holes in the corners:

File:2d-design-with-openscad.png‎

So how do we produce that?

Visit http://www.openscad.org/downloads.html and follow the instructions to download and install.

Once OpenSCAD is installed and you've started it up, you'll be presented with a set of blank panes. Let's whack the following into the left hand pane:

difference() {

    // Plate size overall
    square([75,100]);

    //  Screw holes
    translate([6,6,0]) { circle(2, $fn=50); }
    translate([6,94,0]) { circle(2, $fn=50); }
    translate([69,6,0]) { circle(2, $fn=50); }
    translate([69,94,0]) { circle(2, $fn=50); }
}

What does all this mean?

http://en.wikibooks.org/wiki/OpenSCAD_User_Manual/CSG_Modelling#difference

   difference() {

Subtract the intersections from each other.

http://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Using_the_2D_Subsystem#square

   square([75,100]);

Draw a square that's X=75mm and Y=100mm.

http://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Transformations#translate

   translate([6,94,0]) { circle(2, $fn=50); }

The object in the perenthesis will have it's origin at X,Y,Z. As we're drawing in 2D we don't care about Z so this will always be zero for this case. The origin for our circle is X=6mm and Y=94mm.

http://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Using_the_2D_Subsystem#circle

   circle(2, $fn=50);

The first parameter is the radius, not the diameter of the circle. The second parameter provides a higher resolution when drawing small circles.

Make changes to your design, and then hit F5 to refresh the rendered view of your design.

Once you've got a design you're happy with, save it to disk before moving on.

Now it's time to compile that so that we can export the DXF. You can do this by:

• Hitting F6
• Using the menu Design → Compile and Render (GCAL)

Now we can select Design → Export as DXF. Select a sensible file name in a location you'll remember.

That's our OpenSCAD work done. At this point, we can make changes using Inkscape or go directly to sending it to the cutter.

cylinder(r=5.5 / 2 / cos(180 / 6) + 0.05, $fn=6); Makes a perfectly snug M3 nut trap, loose enough that the nut can be placed by hand, but then snug enough that I can bang the object on my table and the nut stays in place. 5.5mm edge-to-edge is the size of a m3 nut.

Category:Guides Category:OpenSCAD