While window shopping a few different projects for generating CAD models in browser, including replicad, I came across the occasional mention of CadHub and decided to take a look. I like what I see, but the project seems to have lost momentum.

The most visible component of the project is a browser-based interface for code-based CAD, much like what Cascade Studio has built, but generalized across multiple systems. It supports OCCT-based CadQuery as well as OpenSCAD with its own CSG system. But that was merely the first step on the list of ambitions. Its documentation homepage listed how code-based CAD can realize many of the items on my collaborative CAD wishlist, including automatic design verification and visual change comparison (diff) tooling. These and many other long-term ambitions are described on the "Blog" side of documentation page, along with this very informative survey of code-based CAD solutions.

So that all looks great in theory, how does the reality look? And sadly, things don't look as rosy there. Despite all the theoretical advantages of code-based CAD in general, it appears that only OpenSCAD has found any significant adoption and I'm not a fan. (That's a separate post I should write up.) On paper, CadHub supports CadQuery as one of several kernels, but as of this writing CadQuery capability has been disabled. The "it's just Python" power of CadQuery became its downfall: since running CadQuery requires a Python environment, people have abused CadHub to do non-CAD things like trying to run security exploits or mine cryptocurrency using free CPU cycles. This sounds very much like the reasons Heroku free tiers went away.

Another "things didn't work out" problem with CadHub is a consequence from the fact it presents a web-based IDE. Which is great until it tries to work with something that has its own web-based IDE like Cascade Studio. After multiple hacks trying to get the two systems to work together, CadHub threw in the towel.

These and other setbacks must have been discouraging, and probably contributed to the project losing momentum judging by its GitHub commit history. In 2021 it saw updates almost daily, sometimes multiple commits a day from multiple authors. It was still quite active going into January 2022, but the rest of 2022 saw only four commits. The most recent update was in January 2023, the lone 2023 update to date.

This is unfortunate. I really liked where this project intended to go, as it aligns with much of my own wishes. Since it is open source, I suppose I could fork the project and see if I can run with it, but I'd need to learn a lot more web development before I can even understand what's already been done. Never mind trying to add to it. Even if I don't use CadHub directly, though, it taught me a lot more about OpenSCAD I hadn't known before.