Posted by david927 10 hours ago
Ask HN: What are you working on? (September 2026)
Big re-factoring, I have a data model now and am closing functionality gaps with Zola and the like. Also, I wanted actual documentation. No one else seems to care about that.
Check it out! I'd appreciate someone other than me banging on it.
Probably the most interesting thing about it at the moment is the editor. The world, and most things in it, are represented as collections of SDFs. More accurately, they're density fields, but, potato-tomato.
Bonsai has undergone a large rewrite over the last couple years that's nearing completion. A world edit is defined as a bunch of SDF parameters which get projected/rasterized into the voxel grid by a shader on the GPU. One neat thing about SDFs is they've been thoroughly researched and documented by a guy named Inigo Quilez, and they have a lot of nice mathematical properties. For example, you can do a smooth union of arbitrary SDFs to get nice rounded contours where shapes join.
I've written every system from scratch, all the way from the memory allocators and font rasterizer to the collision detector and simulation loop. I even wrote a metaprogramming language as a replacement for C++ templates, which is a whole other story. IIRC the only external dependency is the C runtime library for starting the process and my very occasional use of variadic functions arguments.
For a long time, an explicit non-goal of the project was to ship a game. It sounded insane to me to write an entire 3D engine and then ship a game. As it turns out, I've gotten it to the point where I can actually make a game. I've got a start on the game systems in a closed-source repo, and hope to have a steam page for it by the end of the year.
I'll do some shameless self-promotion and leave some links here for anyone interested in looking at the engine, language code, or some pretty pictures.
https://videohubapp.com/ - an application that lets you browse, search, organize, etc the videos you have on your computer, external hard drives, or network drives.
Online container planner in 3d
As many of us here, I sit too much in my chair during the day and I'm trying to stretch more often and strengthen my back/core muscles.
There are a lot of "free" apps out there e.g. Bend that are helpful but I was annoyed with ads and limitations so I built one for myself. Now I use it daily.
The app is simple, you have about 100 routines to pick from and you can even build your own from existing exercises. Each routine comes with simple images, a link to a Youtube video and a timer. There are a lot of 5 minute routines that are perfect for a short break during work.
There are no accounts and I don't plan on adding any more features unless highly requested by users. I've built this for myself but I'm sharing it here as others might find it useful. Any feedback is appreciated!
it's a weight-training app that helps you train along your "pareto frontier" of weight vs reps. The idea is to train at lower weight-higher rep, medium weight medium reps, and higher weight, lower reps for every movement. I tried to develop my own weight training program following bits and pieces of advice from bodybuilding forums and ended up injuring several tendons in my first year. So I did a bunch of research on tendon strengthening as well as what's most effective for hypertrophy (reps near failure) strength (reps near maximal load) and injury-prevention/frequency (not bringing yourself to failure too often) and designed an app to automatically prescribe and advance weights and reps based on your learned strength curve (Brzycki-like, with an added shape parameter)
The app is designed to make use of the free Cloudflare tier, so I can support thousands of athletes for just the cost of the domain name. I'm primarily interested in understanding the "Fatigue curve" - right now I have some basic per-set fatigue modeling (basically a log-linear strength dropoff) but I think it could be much better characterized with more data. I could go on and on about the modeling but my intention is to keep it free (maybe add some non-intrusive ads on content pages if it ever starts costing me a few pennies a month) but my primary interest is to be able to do statistical analysis on the data.
Github: https://github.com/athos2113/fillvisa-os
Demo: https://fillvisa.com/demo/
US Immigration still relies on outdated XFA PDFs - you can't fill them on your browser. Most immigrants end up printing the form and fill it manually.
So, I converted the PDF forms into smart web forms. They are replica of the official USCIS forms and follow conditonal logic. In the output, you get the official USCIS pdf form filled.
Result so far (paper, 34 trading days): the no-AI control is +13.0%, the S&P 500 is +3.4%, and 25 of the 28 AI accounts are below the control. The best single account is a Grok-written "patience" book at +40%, which I treat as one lucky account in a choppy market, not a finding. At the trade level the AIs and the control look the same: 3,212 closed positions, median +0.06%, median hold about 2 hours. They trade a lot and mostly go nowhere.
Everything is public, including the losses and the retired strategies: https://aitradingcompetition.com/which-ai-is-winning.html and the full trade file as CSV at https://github.com/ckamelhar-collab/ai-trading-arena-data. Paper money only, not advice, nothing for sale on those pages.
The second probe in Boston fixes this and the site can now say "unreachable from Asia" versus "down for everyone". Many of the existing checkers do not do this and they are prone to show false positives.
Site does not use cookies or analytics. Pageviews are counted from the proxy access log. There are 634 curated sites so far.
There are no ads either, it's mostly been for my personal learning experience, hopefully others will find it useful.
There is even a free API and of course a MCP server.
https://downforjustmeoreveryone.com
Any feedback is welcome!