A Topological Picture Book, Rendered | Hacker News Reader

A Topological Picture Book, Rendered

e-infinity.space

147 pointsmathgenius16 comments

This is my project — thanks for the interest. I just made it more mobile / small device friendly.

The app is primarily based on ideas of Hertzmann and Zorin in [this paper](https://cims.nyu.edu/gcl/papers/hertzmann2000iss.pdf), using directions of principal curvature for hatching directions.

Very cool, I made a very primitize plotter before that let you draw on the UV plane and project curves onto the surface (helpful for fundamental groups) / included a time parameter for homotopies. If you're looking for feature ideas I think those would be great! https://tobylam.xyz/3d-plotter

I only see one picture, the Klein bottle on the front page. Are there more? Maybe it's my browser settings or something like that. Firefox 140.14.0esr. Thanks!

Oh I see, never mind! You have to use the "preset" pulldown to select different surfaces. I wonder how feasible it would be for other people to add new ones!

Fantastic project. Love the bells and whistles. I could spend all day here.

Would love to read a bit on how this was implemented (your stack, techniques, etc).

Thanks!

Pretty, and a lot of fun to tweak around the parameters.

I was an undergraduate student of George's many years ago and it's an absolute delight to see these renderings. He used to doodle them on any available surface -- blackboards, notebook paper, napkins, what have you -- often with a fountain pen. He was also big into using computers for visualization and had a number of programs that ran in the CAVE.

I was a grad student of him, all you describe resonates, and i still stay in touch nearing 40 years later. some of the happiest most fun stuff in grad school, and there were endless nerdy fun pursuits. i'm so grateful i learned under him. it was incredible to see him drawing.

In addition to making the sidebar dismissable on small screens, it'd be nice to add touch-action: none to the canvas so rotating the object doesn't get interpreted as a scroll on touchscreens.

Right now, at least in Android Chrome, dragging to rotate only works briefly before it's interrupted.

The spacing and style of the hand sketched lines are really perfect. Was it hard get such clean drawings, even using principal curvature fields?

Very nice. I've been inspired by the same sources and have always wanted a way to render such drawings for any arbitrary 3D model (e.g. STL file). I've played around with that quite a bit, even recently with LLM assistance, but haven't yet gotten it as good as I want. Eventually...!

Great app to play around with. I thought I can think of the implicit form for a cube. I couldn’t (how embarrassing). It’s:

f(x,y,z) = max(|x|, |y|, |z|) - const.

This is awesome, what an incredible project!

Is there a way to hide the menu on mobile? The few pixels I can see do look pretty cool.

Going landscape seems to be a bit better..

Absolutely beautiful.

Reply on news.ycombinator.com