Show HN: Render Arbitrary 3D Boolean Functions (opens in new tab)

(aqnichol.com)

8 pointsunixpickle6y ago6 comments

6 comments

4 comments · 2 top-level

unixpickleOP6y ago· 2 in thread

This is a web demo for creating 3D models in JavaScript. It uses a variant of ray casting that can render any function mapping `(x, y, z) -> bool` in real-time.

It's easy to define very interesting 3D models as boolean functions. In my opinion, it's much easier than creating triangle meshes or composing a bunch of primitive shapes. I had fun making the examples, and I'm curious to see what other people can come up with.

GistNoesis6y ago

You probably should mention the rendering of signed distance fields. The representation is quite similar `(x, y, z) -> double`, and allows for high generative power and more performant ray marching algorithm. You can also get the normal by automatic differentiation.

unixpickleOP6y ago

Good idea, I'll add a reference to SDFs. Didn't think about the normal-via-autodiff aspect, which would be quite useful.

It seems to me that SDFs are very hard to program from scratch, compared to simple boolean functions. Obviously they are easy to implement for compositions of simple shapes, but for things like my text example (and maybe the corkscrew example, although of course that is still a fairly simple mathematical shape), it's less obvious how to implement an SDF by hand.

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photon_off6y ago

I don't have any feedback or strong opinions on this, but the concept of mapping (x,y,z)=>bool and having it produce a 3d object is new to me. This is a very cool demonstration; thank you for sharing.

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