This is Dactyl-ManuForm keyboard created by Tom Short based on Matt Adereth and Jeff Gran's projects:
This particular version is a 4x6 grid generated with modified parameters - a bit taller, with a bit more tent and slightly tilted outwards.
Also it excludes teensy holder and the flexible PCB supports, i.e. it is supposed to be hand-wired instead of making the PCBs. Teency/ProMicro board is attached to the case wall with hot glue.
I used the lowest resolution just to print it faster.
The imperfections around the key holes and inside of the case will be hidden anyway.
Support settings - 60-65% angle is enough, better use grid than lines.
The case can warp a bit, easier to sand it to get a good fit.
EDIT: Added a tent base to work with this Ergodox EZ tent kit:
EDIT2: Added a link to Tom Short project on github