Although the final robots designs are usually edited in a 2D layout editor due to their complexity, it is often extremely useful to begin design in a 3D CAD software for mechanical engineering before exporting to 2D. These CAD programs usually have many more options for creating complex 2D (and 3D) shapes, dimensioning them, and changing single dimensions and having the rest of the design update around them.

We usually use Autodesk Fusion 360. SolidWorks is a very similar option.

Fusion 360 is available for free for educational, hobbyist, and non-commercial use. Its website is here.

SolidWorks currently requires a paid license for research use. Licenses may be available for a fee managed by the Berkeley Mechanical Engineering department (Daniel Teal notes: contact Rene Viray in mechanical engineering; a license was $3000 per seat in 2021).