FreeCAD in the Browser

ccui about 5 hours ago 29 commentsRead Article on magik.net

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79% Positive

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Discussion (29 Comments)Read Original on HackerNews

ebspelman•about 4 hours ago

The launch graphic says "Ported end-to-end by Fable, an AI agent" and it definitely feels that way. Buggy, glitchy, needs some love and human eyes before it's really usable.

NavinF•about 4 hours ago

FreeCAD on desktop is much the same in my experience. If LLMs were mainstream a few years ago I would have assumed the UI was 100% AI generated with zero human input besides a oneshot prompt.

gucci-on-fleek•about 1 hour ago

When was the last time that you used FreeCAD? Even 18 months ago, I would agree with you that it was a buggy mess, but I tried it a few weeks ago and it was super stable. The UI is still a little confusing, but that just comes with the domain, since AutoCAD and Fusion 360 aren't much better.

jazzyjackson•25 minutes ago

I couldn’t get the results described by the intro tutorial 3 months ago, in the parts bench drawing a polygon, snapping was broken.

cui•about 4 hours ago

If Solidworks and Onshape were born after the birth of LLMs, they'd probably be glitchy as hell.

dang•about 4 hours ago

Recent and related:

LibreCAD in the Browser - https://news.ycombinator.com/item?id=48755075 - July 2026 (17 comments)

techbro92•about 5 hours ago

Why would I want to run this in the browser vs locally?

SequoiaHope•about 4 hours ago

Browser can be local. What’s nice about browser based is that browser based programs can run on every device. Though it sounds like this one requires chrome which seems weird to me.

gkhartman•about 5 hours ago

Probably nice to have for those with low income that only have a Chromebook.

devttyeu•about 3 hours ago

(I made this port) Fwiw I personally had no reason to do this port beyond using it as a benchmark of the agentic capability of Fable, where something of this shape is IMO a way better gauge than those dumb X.com 'I oneshot game with models X/Y/Z this is how it compares'

I published the actual prompts, and you can see quite clearly that vs Opus which is ok at implementing one big feature, Fable was really able to push through a good chunk of the port. That said it definitely didn't one-shot the port, it also didn't figure out a broken docker sbx sandbox by itself, and also later needed some gaslighting into thinking that the port is not really that hard (by any human measure it was quite hard given the scope of code involved.. The nearly 200MB wasm binary is mostly code afaict..). So there are some clear patterns of how the model was trained and also roughly the scope of task visible in those traces. What I see is that it likes prompts that would take an L4/L5 2-4 weeks to do with Cursor ~2 years ago, more needs some direction and deliberate prompting.

fragmede•about 5 hours ago

Because then it doesn't matter what you're running locally, as long as you've got a supported browser (Chrome, I'm guessing). It means it doesn't have to make a difference if you have a Window 10 desktop or a MacBook Air or a Chromebook. Go to the web page and look at this CAD.

cui•about 5 hours ago

This. The browser as a universal platform.

Evidlo•about 4 hours ago

Like electron, but it's fine this way for some reason.

s1mon•about 5 hours ago

Onshape is free in the browser as long as you are not doing commercial work. It’s a professional system from the founders of Solidworks that competes with all the top CAD tools.

throwup238•about 4 hours ago

> It’s a professional system from the founders of Solidworks that competes with all the top CAD tools.

Because it's built on Parasolid, the same geometric kernel as everyone else. With ACIS pretty much out the door, almost all the professional CAD packages are just window dressing on the same CG implementation.

SequoiaHope•about 4 hours ago

Agreed. I’m not OP but for six months I’ve been using Claude to build a from-scratch CAD kernel based on Rust and WASM, MIT licensed.

The actual UI still needs a lot of work, but I’ve been focused on the kernel. Fable has helped a lot though Opus was already making great headway.

I’m an OnShape power user going back about ten years, Solidworks before that. I need a CAD system that absolutely works. There is a lot of work to do still, and it still seems impossible to succeed, but I’ve been very happy with where things have been going with it lately.

It’s serverless, local, and browser based. You can load the latest binary from GitHub pages here:

https://sequoia-hope.github.io/waffle-iron/

Click the Assay menu to see the kernel test cases we’ve been using so far. Rapidly closing on 100% support!

throwup238•about 1 hour ago

Heh, me too. I'm on my third rewrite after a bunch of promising false starts.

Unfortunately geometric kernels are one of those things where unknown unknowns will bite you in the ass really hard because none of the content is really in the training data for LLMs and pathological/degenerate cases aren't just common but expected. IME it's not something that can be vibe coded with current models, if ever, without intimately understanding the algorithms.

I can't do a thorough review of waffle iron right now but just off the top of my head: it doesn't look like you have a tolerance context? The tolerances look like hard coded constants (TAU_MODEL/TAU_WORK/MATCH_TOLERANCE/etc) but that's fundamentally unworkable. Each operation and vertex/edge/etc needs to track accumulating errors and apply them to downstream point classification. Interfaces like Kernel::boolean_union(a, b) are the wrong abstraction because it's missing tons of information/functionality like accumulating FP errors, evidence/proofs, rollback, etc.

Keep working at it! It's worth the challenge.

cui•about 3 hours ago

How long have you been building this?

27183•about 3 hours ago

> It’s serverless, local, and browser based.

uhh what..

dd8601fn•about 4 hours ago

Sounds cool. Doesn't work.

devttyeu•about 3 hours ago

Author of the port here, you need a browser with JSPI support, which means recent Chrome, or Firefox Nightly with the feature flag flipped, or Firefox from the future.

devttyeu•about 3 hours ago

I will also note that it's possible to compile this with wasm asyncify, but the result iirc is a ~400MiB Wasm binary that will crash the browser tab before you will be able to do anything useful in it.

cui•about 4 hours ago

Seems it's only supporting Chrome at the moment.

emmelaich•about 4 hours ago

Amazing. How much did it cost?

devttyeu•about 3 hours ago

I made the port, roughly ~one maxed out Claude Max 20x sub, at the bottom of the article I've shared the full claude code transcripts, so you can probably to some rough math on token usage with that.

Edit: to be precise 'maxed out' means one weekly limit on fable used over those 4 days