Modeling Tools

Before discussing 3D modeling tools, I wanted to put out some of the things that I was looking for in a tool:

1. Parametric. The tool absolutely must be built on the idea of parametric design, and allow for ongoing evolution by adjusting the parameters and then re-solving the design.
2. Integrated MCAD/ECAD. When building something that combines something like 3D printing and electronics, it's super helpful to be able to round-trip between the mechanicals and the PCB layout. This can help ensure your shapes all fit the way you expect, including holes and mounting features.
3. Simulation capabilities. This means both things like LTSpice for electronics, but also various forms of FEM like static stress. This helps figure out how something you're designing that has to bear some amount of load (static at least) will react.
4. Rendering. It'd be nice to have some decent rendering capabilities.
5. Documentation capabilities. 3D models are great, but when the rubber-meets-the-road, most organizations are driven by 2D drawings. Being able to create these and have them dynamically updated will be infinitely better than my manual drafting in high school.

For my purposes, I settled on usingFusion360 and paid for a regular subscription annually. See my discussion elsewhere as to the license tradeoffs.

Alternatives to Fusion360

Note that these are all parametric modelers. Parametric modelers use a 3D modeling technique based on computational methodology to manipulate the geometry. It happens using parameters that are (adjustable) geometric properties of a design model.

3DEXPERIENCE SOLIDWORKS

$99.00 for Makers. Based on the recommendations of a friend, this is the application I started with. It is insanely powerful, and definitely "industrial-grade" tooling. The Maker edition does have some limits (such as watermarking things) but likely is fine for most people's use. The main reason I stopped using it is that it crashed more than I would like, and the website is impenetrable. Seriously, it may be the worst website I've ever interacted with, and it's often necessary to get things done. There's a comparison of Fusion360 and SOLIDWORKS you can read.

SOLIDWORKS doesn't work on macOS, although there is a web interface for some of the tools.

FreeCAD

[Open Source, website] The closest thing to SOLIDWORKS or Fusion360. And while I know a lot of people have a lot of love for the tool, I've not had the best of luck with it from a stability perspective. I also find it more difficult to use than either Fusion360 or SOLIDWORKS (which share a huge amount in common).

OpenSCAD

[Open Source, website] Another parametric modeler, but this one uses a scripting language to drive its modeling, rather than inferring the model from the interactive use of the system. This might be easier for some people to think about, and it encourages you to use parameters much more. For a starter system, though, I think it's not super intuitive for most people. You can read the tutorial to see how you feel about it.

Onshape

Free - $2,500.00 , website. Despite being a web-only application, Onshape is a serious tool. Where it excels is in collaboration (obviously), even supporting simultaneous multi-user editing. The "free" (as in beer) version has a couple of limitations that make it potentially uninteresting. First, you can't use it for commercial projects. Second, all your work will be public. Lastly, you're missing both the PCB functionality and the rendering.

Accessories to Make Your Life Better

SpaceMouse

If you do any amount of 3D modeling and can spare a few extra dollars, I cannot recommend the 3DConnexion SpaceMouse Compact nearly enough. It brings you 6 degrees-of-freedom in movement and allows you to interact with a model as though you are holding it. While it takes a day or two to get comfortable with, it's now second nature and a wildly more productive way to manipulate things.

Note that it doesn't replace your mouse/trackball, but instead augments it.

El Gato StreamDeck

Harking back to the old button boxes on CAD workstations, the StreamDeck may be built for streamers, but it works great as a button box for 3D modeling. I have mine installed along with the SpaceMouse in a 3D-printed enclosure.