Al Williams [Williams - OpenSCAD for 3D Printing

When I was in school, many years ago now, I had a few semesters of drafting. Being progressive, we had about a week of computer aided drafting. In those days, that meant punching a few cards that said something like RECT 10 10 5 5 and handing it to a computer operator. Later in the day you came back and picked up a big curly piece of paper that had a rectangle on it. I was less than impressed.

Im primarily an engineer, not a draftsman, and as the state of the art in Computer Aided Drafting (CAD) advanced, it seemed like my prediction was correct: no one wanted to write cryptic commands to drive drawing. They wanted to use a mouse or trackball and draw on the screen as if it were paper.

At about the same time, things were changing in the electronics industry. When I worked for a major semiconductor manufacturer, our computer chip designs were on huge rolls of paper that had been meticulously drawn. As computer design moved from table tops to computer workstations, it seemed obvious that you wanted tools that let you draw those same huge rolls of paper virtually.

Obvious, perhaps, but also wrong. Drawing computer circuits gave way to a much better system that used computer-like languages to describe circuitry. Instead of drawing 96 interconnecting lines, you could write something like ramdata=ram_cs?data[31:0]:32bz;

If you dont know the language, that may seem cryptic but it is compact, succinct, andmost importantif I decide to change the bit width to 16 or 64 or 256 it takes just a second to make that change.

A lot of drafting has gone the same way. There are tools that let you draw as though your computer screen is a piece of paper. Thats not OpenSCAD. OpenSCAD is the great grandson of the old CAD punchcard system I used in school. Of course, there are no cards, it is less cryptic, and it creates 3D objects with relative ease.

Just as computer design moved away from drawing, even the big drawing-style CAD tools often some way to do parametric drafting. OpenSCAD is the extreme. You draw nothing. You describe everything. It shows you a picture of what you described so you can refine your description.

This book will teach you the fundamentals of using OpenSCAD to develop 3D models for printing. You can do a lot of things with OpenSCAD, but Ill only focus on the parts that help you get output from your printer.

I wont talk much about the rules of what makes an object good to print. If you are interested in that, you might want to read one of my other books, Understanding 3D Printing . However, the exact nature of what you can do and cant do varies by the type of printer and material you are using. In general, though, an object needs to have a flat base to sit on the print bed, and there are usually limits to how much material can hang over an edge or cross over a void.

OpenSCAD isnt the best choice for all kinds of 3D modeling. It excels as what I think of as engineering models. Things like front panels, bearings, shimsthings that have regular shapes that you might draw in a drafting class. It is not so good at modeling things that have irregular surfaces like animals or plants or people. You might be able to model some things like that in OpenSCAD, but it would be difficult and frustrating compared to using a program that is made to model artistic objects (like, Blender, for example).

Inside this book, youll find easy-to-digest Chapters that will help you get the most out of 3D drafting with OpenSCAD. If you havent used OpenSCAD, you should probably work through Chapters 1 to 4 in order. The remaining chapters cover more advanced techniques that you could revisit as you need them in any order (more or less).

It is tempting to pad out a book like this with lots of graphics of 3D models. You ll see some in these pages where they help illustrate a point. However, you should really read this book with OpenSCAD open on your desktop. Type in or copy and paste the example code into OpenSCAD and see the output for yourself. Think about a change and try to make it work. Youll learn more that way than just looking at screenshots on the page of the book.