I am a software dev for a living so what I mean by low brain space is I don't really want to be messing about with config files, setup and complicated UIs. I already have far too much brain space dedicated to Blender, but I just can't seem to get it to work well for precise measurements and CAD style work.
Fusion360 used to be free but that appears to be ending, also cloud-based lock-in(files are on server).
freecad used to be quite buggy, but latest versions are quite workable.
I mself started with one or 2 tutorials in fusion 360 (they appear to be more clear to me compared to the freecad tutorials, and concepts are the same). Then switched to freecad, and this seems to work fine.
The parametric sketching (although a simple concept) took for me the most time to really grasp and understand the significance.
I haven't used it but it's been popping up in other threads since the licensing changes for Fusion360.
Bear in mind, though that everything else (Microstation, DraftSight, etc.) Aren't much better. For a problem domain like roadway design, the difference in productivity between something like freeCAD or LibreCAD and AutoCAD Civil3D is like the difference between having a printing press and a lump of charcoal. I really admire the effort, but there is a moat between industrial and FOSS software for the AEC industry that takes more expert developers and more man-years than hobbyists can provide.
* FreeCAD - Very powerful, very buggy/unstable.
* SolveSpace - Very powerful, takes time to understand the interface.
* OpenSCAD - Great for simpler objects.
* Blender - Not very good for CAD modeling, but with non-destructive modifiers and the new Extrude Manifold it can be used.
Personally I use Blender all the time for 3D printing. There are some tricks that can help a lot with precise modeling. For example you can draw a plane, but instead of extruding it you can use the solidify modifier to give it thickness. Then the thickness is non destructive. You can also view all edge lengths which help you to check if everything is ok. Since v2.9 you can now use Extrude Manifold which is not precise but works a little like Sketchup making some modeling much easier.
And a lot of time my workflow is: Create something in FreeCAD/OpenSCAD -> export to Blender (STL) -> add finishing touches -> 3D print.
It doesn't help that each version gets a lot of superficial UI changes so tutorial videos will often get you part way then some menu option no longer exists and you're stuck.
I plan to try SolveSpace next as it seems to be a lot more stable - though in principle also a lot more limited.
I had to 3d print something recently and was very happy with OpenSCAD. Not only it is scriptable, but it is script first (and only), with a very simple syntax. For people who write code already, it's a much more natural approach in my opinion. You can create functions, loops, parametrise, comment out part of the code, etc.
So you need to import to some other program and export from there. That's how I got into FreeCAD. But once you're in FreeCAD you realize you can do everything there.
There's a whole fillet / chamfer library using masks and such, but I've found that you can go a looong way with just basic shapes that start out chamfered/filleted, and unioning and differencing them.
It uses lua to be scriptable much like openscad, but it's got GPU support, so you can also describe surfaces as signed distance fields - in shader code...
It doesn't seem to be open source (yet?), but there are contributors listed [0] (it came out of inria, the french university, sylvain lefebvre being the lead dev[1])
Check out %appdata%\IceSL\icesl-models or thingiverse[2] for examples.
edit: formatting
[0] https://icesl.loria.fr/about/
[1] https://www.antexel.com/research
[2] https://www.thingiverse.com/search?q=iceslIt seems to be mainly a slicer, so maybe the non-open part is just the slicer? Some parts are open and available on their github account: https://github.com/shapeforge
I believe the popular route is Fusion. (Decidedly NOT open source)
Here's an example: say you want to punch some holes to mount components on a chassis. Say, furthermore, that you want to mount those components at an angle.
Here's what you do in Fusion:
1. Draw a sketch.
2. Rotate the component on the sketch about its center.
3. Subtractively extrude holes through the chassis.
In Fusion this is trivial and natural. Believe it or not, FreeCAD does not support #2. Want to mount several components at different angles? Fuck you, you need to draw each one of them pre-slanted already.
Select the object, set orientation in Placement / Axis / x,y,z
- Create a square via the CreateSquare[0] icon
- Put the lines as construction line
- Constrain the holes to the corners of the square.
- Add an angle constraint on one side of the square as you need.
It's easier than constraining your holes on a rectangle on which you have to replace the horizontal and vertical constrains afterwards. And you get to keep all those parametric variables that make changing something afterwards so easy.
In your case one can for example use use the NormalToEdge map mode, specify the degrees of Roll, and then use a Pocket operation on the sketch to make the holes at that angle.
(If you haven't seen that, and you have projects in F360 formats you're assuming you'll be able to export - you might want to go export them all into some other format now, while you still can...)
Luckily my not trusting web apps means I am already backed up in non autodesk formats. But exactly why when sketchypoved to wrbapp I said I wouldn't trust it
The Part workbench makes you create your object using CSG primitives which you size and position using the properties editor, which is just super painful.
In Part Design, you create sketches of 2d profiles and then pad them up, pocket them in, revolve them around an axis, sweep them through a path, etc.
Part Design just seems much more convenient and powerful.
The only thing you can't do in Part Design is create 3d paths like helixes, but fortunately you can create these using the Part workbench and still use them as paths in Part Design.
Also (opinion) it kind of sucks. At least the gratis version doesn't support any sort of parametric modeling. I've been using it because it's gratis, but I've been looking to switch for a while. Now that F360 is off the table, I suppose the decision space has gotten smaller.