OpenSCAD: The Programmer's Solid 3D CAD Modeller

I use OpenSCAD as my primary design tool for 3D modeling. I get things done, but it isn't easy, and it's hard to recommend it to other people. OpenSCAD really requires the user to mathematics, trigonometry, mental visualization, and programming beforehand as prerequisites - unlike mainstream CAD programs which are more point-and-click friendly. Performing fillets and chamfers on corners is quite tedious, and describing a screw thread as a polyhedron is a nightmare, but I overcame these challenges.

On the plus side, I like these things about OpenSCAD:

* The software is open source, so price or pirating are not barriers, you can use it as much as you want on any computer you want for as long as you want, and it can never be taken away from you.

* The program is small and easy to download, not some multi-gigabyte sprawling software package.

* I think you learn to declare variables for parameters very early on, and it feels natural to make every design parametric from the start.

* The textual nature of 3D models means that I can use Git version control, diff between versions, and leverage similar developer-oriented tools that I use for general programming. I suspect that CAD programs that use binary file formats will have to come with their own diff tool and version control system.

* By reading source code, it's possible to follow the thought process of how a 3D model is constructed, and carefully make modifications in the middle of a chain of operations that later operations dep […]

If you look at this and you think "wow, I love the idea of CAD-as-code but I wish it was a more sane language" then have a look at CadQuery: https://cadquery.readthedocs.io/en/latest/quickstart.html#qu...

(I recommend CQ-editor for an easy install: https://github.com/CadQuery/CQ-editor/releases/)

It's a similar idea to OpenSCAD, but embedded in Python and using a better geometry kernel. Want to fillet a box in OpenSCAD? Sure, either take the convex hull of 8 spheres, or the minkowski sum of a box and a sphere. Want to fillet a box in CadQuery? .edges().fillet()

Now I'm hearing some protests about Python, but consider this example OpenSCAD code:

x = 1;

echo(x);

x = 2;

In most languages you would expect this to print "1". In OpenSCAD, the last assignment wins and it prints "2".

There's a long history of programmers trying to reduce 3D design to programming. I still remember POV-Ray, which was a big thing in the 1990s. But in the end, it's just a very inconvenient way to iterate on shapes by editing code. Kinda like drawing a comic strip by writing SVG by hand. Effortless interactivity rules.

Many CAD programs incorporate parametric modeling, scripting languages, or Scratch-like "block programming" tools for when you actually need flexibility for a specific assembly. But that's where it belongs: an add-on for an interactive modeler. You don't need to write code draw a helix, but if you need a variable number of scaled copies, there's a parametric tool for that.

I guess these tools may be useful to LLMs because it's cheaper for them to generate a program than to perform computer-use tasks in a UI. But I wouldn't recommend humans to start with OpenSCAD.

The one you want is the experimental build, it is way faster to the point that 'preview mode' should be disabled. I use OpenSCAD a lot, it ties right into my workflow and plays nice with versioning and re-using modules from one project to another. Over time I've built up a nice library of parts that I can quickly customize for whatever it is that I'm building. Latest project: pick-and-place machine modification for Prusa MK3 3D printers (an interesting challenge, to put it mildly), now working on some robotics stuff.

The most important thing about OpenSCAD for programmers to remember is that it looks as if you are programming but really you are describing geometry and objects so things like variables and such do not quite work in the way you would expect from a programmers point of view.

Oh, since this came up, for people who like code CAD and want to try something more powerful than OpenSCAD:

https://github.com/yuechen-li-dev/Aetheris/

Not an OpenCascade wrapper, it's based off my own experimental BREP geometry kernel. So, fillets/chamfers work, booleans works fairly robustly, surfacing, sheet metal, etc all works decently, it exports STEP AP242 by default.

Haven't had time to get the AIs to write a more up to date documentation and polish the language server. Not the easiest thing to use right now, so, using it through Codex/Claude Code or CLI is probably the easiest way to get started.

Still working on the webUI currently, in case someone want to DIY the UI. Note that the WASM compilation path is still unoptimized and way slower than the RyuJIT C# compilation though.

https://github.com/yuechen-li-dev/helioscad

I have been using OpenSCAD to create cool geometric designs for 3D printing on fabric, with great results. The functional model is likely unfamiliar to most developers, but I have found that I can be efficient and productive with it.

Check out my repos of OpenSCAD objects at https://github.com/jeffbarr/OpenSCADObjects and Truchet Tilings at https://github.com/jeffbarr/TruchetTilings .

My code kind of looks like the C that I wrote in the 1980s, with lots of braces and careful indenting -- not sure if that is a bug or a feature.

As another commenter noted, use the latest nightly build for best results.

In practice, I have found better results with `build123d` than with OpenSCAD if one is using current agents with current models. It's a cool tool, yes, but something about the workflow makes it hard for present day agents to work with. Perhaps some kind of custom harness would do the trick, but `build123d` works with Opus 5.5 in more cases than OpenSCAD.