OpenSCAD

 OpenSCAD presents a bit of an oddity for me as far as topic categorisation goes and in the best possible way. OpenSCAD is a freeware program which allows you to use code to describe a series of objects and transformations of those objects and how they interact to create 3D models that can be exported to .stl file, sliced in your favourite slicing engine and then 3D printed. I'll say that again, OpenSCAD allows you to build a code library that translates to 3D objects and print them, bringing all the power of repeatability, modules, libraries and everything else that's great about code to your own 3D printing designs. Amazing!

http://www.openscad.org/

Where to Start

 Go to the above website and download the right version for your operating systems, it will run on basically anything and either processor architecture. then 

Here's a comprehensive description of the language:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language

And of course here's the cheat sheet:
https://www.openscad.org/cheatsheet/index.html?version=2019.05

A Whistle-stop Tour?

Ok so here's a very quick way of understanding and using the code for OpenSCAD.

Comments

 As in a lot of C languages you can amke use of a double forward slash for line comments: // and a forward slash and an asterisk to open a block quote and an asterisk and a forward slash to close one: /* block quoted comment */

Unique Settings

There are a few $