Code Your CAD with OpenSCAD
OpenSCAD is an excellent prototyping tool for creating 3D and 2D designs. OpenSCAD's killer feature is parametric design. With a few simple shapes and a short script, you can create intricate designs that would have taken hours to create manually in a traditional CAD program.
Of course, Bitbeam is not that intricate. It's just a beam with holes -- a "holey poley". However, getting those holes perfectly placed and sized correctly is tedius to do manually.
Most OpenSCAD tutorials focus on its ability to create 3D designs that you can use in a 3D printer, like a MakerBot Thing-O-Matic. But I'm not using a 3D printer to create bitbeams. I only need a laser cutter, which means I only need 2D output. I'm using OpenSCAD for its ability to crank out variations of bitbeams in different lengths, so I can quickly create a laser-able "kit" of beams.
Below you'll find the OpenSCAD source file I use to create my beams. It depends on a DXF file called "circle-4.8.dxf". The source for the DXF file is included in the Gist. [Update: I figured out how to draw the circles without requiring a DXF file. (It's a long story.)] It's all MIT licensed. (Yeah, OSHW!)
Now that I have a basic beam defined in code, I can use the "beam" module to create various kits. For some designs I'm working on, I'll need lots of long and short beams. Here's an OpenSCAD file I used to bang out a bunch of beams in many different sizes.
Which will produce this output:
