Hacker News
A Topological Picture Book, Rendered
106 points by mathgenius
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11 comments
e-infinityspace
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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.
sevensor
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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.
jjtheblunt
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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.
sheept
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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.
ekzhang
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The spacing and style of the hand sketched lines are really perfect. Was it hard get such clean drawings, even using principal curvature fields?
fogleman
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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...!