3 ms·

While there are lots of similar efforts, the bidirectional interaction struck me as quit promising; you can apparently push/pull on features and have the Scheme

by twarge 5y ago

While there are lots of similar efforts, the bidirectional interaction struck me as quit promising; you can apparently push/pull on features and have the Scheme code update. There also seems to be an emphasis on correctness in the code, which sounds great to anyone who ever tried doing real work in FreeCad, though of course the gap in functionality is vast.

dTal 5y ago
I actually don't know of many similar efforts. The only comparable project to this one is curv [0] Coding shapes with signed distance fields is, unfortunately, highly impractical for CAD; operations tend to compose poorly (most operations a) assume euclidian space and b) distort space away from euclidian). But it's a pretty nice medium for generative art, and Scheme is a beautiful language to do it in. [0] http://www.curv3d.org/ http://www.curv3d.org/
- Y_Y 5y ago
  I really don't know much about this, but do people often do CAD in non-Euclidean geometries? Outside of art and black holes and stuff, of course.
- mkeeter 5y ago
  libfive is unusual in the SDF space in that it doesn't assume Euclidean space, or even Lipshitz continuity! It uses interval arithmetic, so its evaluation is conservative by construction; shapes with weird SDFs may evaluate more slowly, but they won't be wrong. This means that you can go wild with geometric and coordinate transformations – even weird things like twisting or attract/repel will work fine. (the only requirement is C0 continuity, which is the bare minimum; otherwise, a point could be both inside and outside the shape depending on which direction you approach it from)
  - elcritch 5y ago
    Is there a paper or more in depth resource for this? I've done continuum mechanics and FEM, but im curious to learn how SDF is unique. The projects looks very interesting!
    - mkeeter 5y ago
      As a matter of fact, I also wrote a SIGGRAPH paper on GPU-based f-rep rendering that was discussed on HN two days ago! https://www.mattkeeter.com/research/mpr/ https://www.mattkeeter.com/research/mpr/ https://news.ycombinator.com/item?id=26873691 https://news.ycombinator.com/item?id=26873691 There's also a good Twitter thread here: https://twitter.com/CasualEffects/status/1385389913881858054 https://twitter.com/CasualEffects/status/1385389913881858054
      - elcritch 5y ago
        Thanks!

by twarge 5y ago

dTal 5y ago

I actually don't know of many similar efforts. The only comparable project to this one is curv [0] Coding shapes with signed distance fields is, unfortunately, highly impractical for CAD; operations tend to compose poorly (most operations a) assume euclidian space and b) distort space away from euclidian). But it's a pretty nice medium for generative art, and Scheme is a beautiful language to do it in. [0] http://www.curv3d.org/ http://www.curv3d.org/

Y_Y 5y ago
I really don't know much about this, but do people often do CAD in non-Euclidean geometries? Outside of art and black holes and stuff, of course.
mkeeter 5y ago
libfive is unusual in the SDF space in that it doesn't assume Euclidean space, or even Lipshitz continuity! It uses interval arithmetic, so its evaluation is conservative by construction; shapes with weird SDFs may evaluate more slowly, but they won't be wrong. This means that you can go wild with geometric and coordinate transformations – even weird things like twisting or attract/repel will work fine. (the only requirement is C0 continuity, which is the bare minimum; otherwise, a point could be both inside and outside the shape depending on which direction you approach it from)
- elcritch 5y ago
  Is there a paper or more in depth resource for this? I've done continuum mechanics and FEM, but im curious to learn how SDF is unique. The projects looks very interesting!
  - mkeeter 5y ago
    As a matter of fact, I also wrote a SIGGRAPH paper on GPU-based f-rep rendering that was discussed on HN two days ago! https://www.mattkeeter.com/research/mpr/ https://www.mattkeeter.com/research/mpr/ https://news.ycombinator.com/item?id=26873691 https://news.ycombinator.com/item?id=26873691 There's also a good Twitter thread here: https://twitter.com/CasualEffects/status/1385389913881858054 https://twitter.com/CasualEffects/status/1385389913881858054
    - elcritch 5y ago
      Thanks!