
Dactyl builds seem to mostly be done by people who either know what clojure is (professional keyboard pokers), or at least people who are in the electron herding/plumbing industry. This means that there’s not a whole lot of build guides written by people who know to hate STLs with a burning passion, and who might actually want to use typical feature-based CAD (and not keyboard mashing) to edit their keeb to their liking. While there are many reports of being able to open openscad files in freecad, that did not work for me.
Fortunately joshreve used python to make a generator that can create a STEP, albeit one with a lot of self-intersecting and bad geometry that prevented solidworks from opening it on the first go. After a few hours of editing, I was able to knit up all the surfaces and make a solid body. But shoutout to joshreve-this work was critical!
In the spirit of making this available to other mechanical types, you can get the fixed up .sldprt and .steps from here.
Goal: see if I can get used to this keyboard

I picked an extremely whacky keyboard to build, because why not? Worst case I get hooked on it, spend a lot of time making a keybord nobody else will use, and I have to build my own keyboard for the rest of my life. Best case, I make it and decide its awful and retreat blissfully into querty land.
Unlike most people who seem to tout the wonders of the manuform, I do a lot of CAD. CAD means you use a mouse, and you have to type a lot of numbers. I’d like to see what the manuform can bring to that- specifically, can I right-hand-mouse and left-hand-numpad? Would I like a layer for common shortcuts just for specific programs? Would it be cool to have a trackball built into my keyboard? I have questions that have not been answered by a cursory google search and so I will have to find out for myself.
What did I change?

As a mechanical-type engineer, I like things to fit together without having to drill extra holes or to hot glue in connectors. So it was important to get the case holes right, to prevent that. The micro however, will be taped (double sided) to the interior, since there will be no force on it from removing connectors etc.

I also moved the screw bosses to the inside of the case, since they will look better there. they are sized for M3 heat set inserts from McMaster.

Of course, there has to be some frivolous embellishment on it because it is both 3d printed and a keyboard. Instead of spending hours on this, I just threw some text on the “knuckles” of the keyboard. “PROTO–TYPER” seemed to be appropriate, as it is a prototype to see if I like split weirdo keyboards enough to keep using them.
Wiring

There are better guides out there on this but overall it is straightforward to wire these keyboards and if done carefully, there is little danger of anything shorting out, and even if something is shorted, its easy to fix. If I were to do it again I would use enameled copper wire or fully stripped 28 ga wire and a wire wrap tool, with cut to size ptfe tubing as the insulator. I think this would be easier than carefully cutting 20 or so small wires per row. I will say that it took a surprisingly long time to solder this, even for someone who is fairly good at fiddly soldering.
Update: A Few Months Later
It took me a few months to button this project up, and in the mean time I have been using the keyboard. It is now my daily driver- for everything. Surprisingly I have been spending most of my time in kicad and altium instead of solidworks, but the time I have spent in all three programs has been pretty pleasant.
I think the most challenging thing will bet to remap all the important shortcuts to the left hand, and for those that cant be remapped, to make an application specific layer. For example, the ‘M’ key is really important for moving things in kicad- but its on the right hand. That means that to move stuff, one of my hands has to come off the mouse or the keyboard.
One thing that has been surprisingly nice is my navigation layer, which makes the left home keys arrow keys, and the right home keys the mouse directions. the thumb keys on the right side become left and right mouse clicks. I would say if I am not in a cad program, my hands stay on the keyboard, which is nice! The only issue is that its easy to get stuck in a layer (or my numkey layer) and not know that I am in that mode when I first sit down and start typing my password. some kind of indicator will need to be built into the next version.