4/17/2023 0 Comments Openscad assemblyI treated all dimensions as mm, but when importing the SVG into Corel, the sizes were wrong. One oddity of OpenSCAD is that it creates unitless geometry. I used Corel Draw, but Inkscape and other vector editors work fine. This needs to be cleaned up in a vector editing program. You can see in the SVG above that OpenSCAD exported vectors with 0.5pt and filled polygons. The SVG can’t be printed directly because my laser only cuts hairline (0 width) vectors. Even though my wheels are fully parametric and I could generate all the variations in one run, I rendered and exported each wheel separately to give me the flexibility in cleaning up the SVG.Īll of the CAD files and SVG exports that I cut can be found in my github nodebots repo. There aren’t any options to control the SVG, so you’ll probably have to do some data cleanup. Once you have finished the design in OpenSCAD, press the “Render” button to project the geometry onto the XY plane, then export an SVG. The final wheels are about 1mm narrower in all dimensions. The only critical tolerance is the mating holes to the servo motors, and I just tweaked the geometry through trial and error. The laser I used cut a kerf about 0.5mm at best focus. You will definitely have to plan for your specific laser when cutting accurate parts. Most laser cutters can generate a decent tool path from a simple vector drawing, but none cut narrow enough kerfs. OpenSCAD does not have any concept of a cutting tool’s kerf. OpenSCAD definitely works best when creating solid models for 3D printing, but simple models can be laser cut if you can live with two limitations: you must design flat parts, and you must allow for the cutting tool in your dimensions. Constructive solid geometry will be a brand new idea to many programmers, but it has so many similarities to set operations that it too will probably be quickly learned. OpenSCAD uses a custom language, but the syntax and features will feel familiar to most programmers. I defined one main module to create the wheel geometry and a helper module to create the servo motor mounting holes for attaching a wheel to a motor. It’s actually impossible to draw anything by clicking in the graphics display. ![]() You can see in the screen shot above that OpenSCAD creates things by running a program. ![]() The software has seen many improvements since then, but has kept true to the idea of a simple, programmable solid modeling system. The programming area is larger than the graphics display!Ĭhris Farber wrote about OpenSCAD in 2013. If you’ve ever seen CAD software before, OpenSCAD is a little shocking. It’s definitely not a replacement for a commercial CAD system such as Inventor or SOLIDWORKS, but I was able to create fully parametric wheel designs much quicker and easier than if I tried to use a 2D drawing program. OpenSCAD is a great introduction to CAD for programmers that’s fun to use and easy to learn. ![]() What better time to learn how to use a new CAD package? I’m helping with an event in Ann Arbor and we needed over 40 robot kits for people to play with. International Nodebots Day 2015 is July 25.
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