PySdfScad VS turbo

> To clarify, can this method be used as a fully functional replacement to BREP for a mechanical (machine design) CAD system?

I think so, but there are some open problems. Also it depends on the senior people. Inigo Quilez is a world class expert in this domain, and for the most part we're copying his work, get him on board and you'll be golden.

Fundamentally it makes sense, BREP is about representing boundaries and you can definitely use SDFs to represent the area under a boundary (infinite SDFs are possible, although obviously you can't turn them in to a mesh). Enclose a volume with boundaries and you can mesh that out just fine. A bit different from CSG-based SDFs, but entirely plausible.

>what approach would you recommend?

If I was to do this I'd take the constraint solver from solvespace (same one used in this post) and start using it to generate SDFs. At that point you're already 80% of the way to your end goal.

I mean if I was personally to do this I'd start by making a system that implements everything openscad can do, try to get some funding going, and than add in a solvespace based workbench for doing 2D cad that you can import into an openscad-ish language. You can see my efforts here: https://github.com/traverseda/PySdfScad

That's tackling it from a different angle than BREP though. I think that openscad but better is a surprisingly viable thing though, especially if you use it to do things like generate the gears/screws/whatever you import into your BREP based CAD project. Use scriptable CAD as the underpinning for more advances CAD.

> How long would you estimate it would take for three full time senior developers to get a useful system out?

Well define "useful"? Honestly I think you can get 80% done in under a month. I built the first pysdfscad in a week or two and replicated 80% of openscad's features. Fogleman built the library I used for pysdfscad in under a month.

I'd expect something pretty good in under a year at that kind of rate. There would be some outstanding problems, like it would be a challenge to figure out how to apply a fillet/chamfer to an edge, but not an insurmountable challenge. Geometry import is another place where you're going to spend a lot of time/money but is very important.

So let's say two or three years with three very competent seniors working on it to get a pretty good CAD program, with a GUI.

Depends on exactly what I'm making, the answer is probably different if I'm making like a chat app or something more data centric.

For something really minimal, an internal tool, I'd probably use grist. Grist is a "no code" spreadsheet program that is open source and works on a relational database. I just threw together an inventory management system for my weekly dnd group in a few minutes, and I've shared it with the group. I find the relational mindset grist uses a lot easier to reason about than traditional spreadsheets.

The next level up would be django with htmx. Very minimal javascript, I might embed a javascript "applet" like a map into it if needed. This covers 99% of data driven apps.

If I wanted to build something like say discord I'd probably use a pretty similar stack for the MVP, but with server-sent-events (htmx with server sent events is nice) and web components for more complicated interactions. That's probably why I'm not in charge for building complicated single page webapps with a lot of interdependent state though. I maintain this approach should work but haven't had a real chance to test it in the wild.

If I'm writing CAD software I'm probably going with QT/python/(numpy/jax/compute-shaders/sympy/etc). Python might not be the fastest, but when you're accelerating it with one of those machine learning libraries it can be really powerful. I've actually been working on something CAD-ish using that stack here: https://github.com/traverseda/PySdfScad

That's probably roughly the same stack I'd use for things like computer vision, machine learning, etc. Ironically anything where performance is important I'd probably choose python over a compiled language.

Mind you the QT python documentation is really not great, for a really minimal MVP I might swap qt out for pyimgui which is amazing for rapid prototyping but is going to be a real pain to do things like syntax highlight a text editor or embed HTML content.

Embedded electronics? Probably micropython on an ESP32 for an MVP. A REPL on your microcontroller is really nice. Robotics I'd probably use buildroot to build a custom linux distro.

I don't have much experience with mobile development, so I'd probably end up using QT with python and pyqtdeploy, but that's not an approach I'd recommend anyone else follow. I'm keeping an eye on Tauri in that space, although I really wish they made it easier to bundle in things that aren't single page javascript web apps (like a python application).

So yeah, mostly I'd use python. Master of some trades, jack of a bunch of others, it's flexible and powerful enough that I feel happy to have specialized in it, even if deploying apps to end users can be finicky and annoying. I'd avoid the javascript ecosystem as much as possible, and where I'd have to use javascript I'd prefer to make self-contained web components.

I also recommend checking out the docs for Stimulus and Turbo to familiarise yourself with all their features and the APIs used in this series.

https://github.com/hotwired/turbo

Turbo 8 remove typescript without using JSDOC

Experiment using Turbo to drive front-end behavior: "Turbo 7.2.0 (currently in beta) allows you to define your own Stream actions which can be any JS code you want. By combining a custom Stream action or two with web components, you can essentially drive reactive frontend behavior from the backend stupidly easily. Loooove it! 😍 […] For a turnkey example, you could check out https://github.com/hopsoft/turbo_ready " —Jared White on The Spicy Web Discord

This handles disconnection (as could be done by any destructive change to the DOM, like navigating with Turbo or htmx, I'm not even talking about using the element in a JavaScript-heavy web app) but not reconnection though, and we've exited early from the connectedCallback to avoid initializing the element twice, so this change actually broke our component in these situations where it's moved around, or stashed and then reinserted. To fix that, we need to always call addSparkles in connectedCallback, so move all the rest into an if, that's actually as simple as that… except that when the user prefers reduced motion, sparkles are never removed, so they keep piling in each time the element is connected again. One way to handle that, without introducing our housekeeping of individual timers, is to just remove all sparkles on disconnection. Either that or conditionally add them in connectedCallback if either we're initializing the element (including attaching the shadow DOM) or the user doesn't prefer reduced motion. The difference between both approaches is in whether we want the small animation when the sparkles appear (and appearing at new random locations). I went with the latter.

If you think you have seen enough Rails magic, you are mistaken my friend. Rails have a new trick up its sleeve: Hotwire. And with the magical Turbo tool that comes with it, you can create modern, interactive web applications with minimal, or sometimes no JavaScript at all, providing users with an incredibly smooth experience.

There is also Turbo and the frameworks who adopt them, Ruby on Rails, PHP Symphony and possibly others that solves the same issue in the same manner as HTMX. And the choice for HTMX is only a personal taste in this, but you should definitely learn about this, this is as cool as HTMX!

Most controversially, the Turbo framework dropped TypeScript support altogether after assessing that strong typing was the culprit behind poor developer experience.

Turbo[0] has been solving this for years. Quite the contrary, front-end frameworks have started to think "sending JSON is good, but actually sending HTML could be great!".

DHH's presentation[1] during Rails World 2023 is quite interesting in that regard, I recommend you give it a go (start around minute 16). I am actually very excited with his vision of the web.

[0] https://turbo.hotwired.dev/