OpenScad looks interesting, seems to be considerable discussion on comparing it with FreeCad.
Can't get my head round Cad programs these days, too many years since I had to get my head round such, but I have recently been introduced to OpenScad and have managed to manipulate odd designs from the open source libraries to see how you can easily modify a project using an existing library.
For instance, the following puts the thread on the item below and only needs two numbers changing to change pitch and diameter, as a stub to the basic cylinder library.
screw_thread(38.1, 3.175, 30, 25, PI/2, 2);
tr1.jpg [ 10.32 KiB | Viewed 240 times ]
tr2.jpg [ 12.37 KiB | Viewed 240 times ]
just a traveller on the road of time.Bits & Pieces Gallery