3D design is often considered a difficult and costly endeavor for those with an invention idea — either you have to buy expensive software, or hire a qualified modeler or designer. Fortunately, there are many free 3D computer-aided design (CAD) packages available (web-based and downloads) to help get your prototype started and ready for production.
There is a learning curve for any new software package you decide to use, but here are four that are considered some of the easiest to learn and use.
Tinkercad is viewed as a basic, kid-friendly, 3D modeling app, but it is much more than a simple web app and more robust than most people realize. There are advanced features in Tinkercad and small business owners are using it to design and create complete products. Files can be saved for 3D printing, of course.
FreeCAD is what is known as a parametric 3D modeler, as in, the software allows you to modify designs by changing parameters, such as, dimensions or density. Most often this is from a dimension – you can change the parts or components graphically by dragging the corner of an object, for instance, but you can also just enter in a numerical change and it will adjust the model accordingly. FreeCAD is open source (LGPL license) and completely modular, allowing for very advanced extension and customization.
OpenSCAD is popular, but different than the other packages mentioned above in that it does not focus on the artistic side of 3D modeling, but on the CAD-specific approach. Their tagline captures it best: "The programmers solid 3D CAD modeler." So, it makes it the more technical package in this list, but it has great reviews. If you are not interested in trying the “artistic" approach, this may be your software.
Blender is one of the best known 3D design software programs, partly because it is free and open source, but more so because it is a robust 3D creation suite. This software package gives you the tools to move through the entire range of 3D — from modeling, rigging, animation, simulation, rendering, compositing and motion tracking, to include video editing and game creation.
While these four will serve most readers, if you have more technical or specific needs, here are two bigger lists of CAD software that may help:
Finding the Right 3D Modeling Software For You on the MatterHackers site and Top 10 best free 3D modeling software tools for 3D printing at 3Ders.org.
As you will find with these software tools, 3D design and modeling does not have to be an arduous experience. There is little risk and with just a bit of time invested, you will find yourself modeling new product ideas and getting ready for the production line.
Two final notes: If you If you somehow find that you need a more mainstream CAD package, most of the major 3D software packages offer some sort of extended trial for the entrepreneur, small business and startup: Autodesk, Solidworks and Onshape each have free or low-cost options.
If the Do-It-Yourself path does not work for you, then read 3D Printing Services - Turn Your Idea into a Product, which offers several service bureaus, such as Shapeways and ProtoLabs, where you can get help creating your first prototypes.