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.

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.

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.

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.

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...!

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.

Absolutely beautiful.