logoalt Hacker News

YuechenLitoday at 5:34 PM1 replyview on HN

https://github.com/yuechen-li-dev/Aetheris

So, yeah, mine is full geometry kernel that was made for CAD. I'll do a full write-up on Show HN later as there is just way too much stuff to cover for the project. The gist of it is that it is a compiler for 3D models that takes the high-level language, which I named Firmament, and lowers it to STEP AP242 mapped BRep in C#.

So, for SDF, it was originally conceived as a method to solve the general case 3D BRep boolean problem through methodology similar to libfive/Fidget in FRep directly. The problem is that we immediately ran into the same wall that everybody else did attempting to recover mesh/BRep structure from the SDF blob, spent like a week doing BRep patches for it, before we ultimately concluded that it was not really possible to do as FRep is a lower representation than either BRep or mesh. It's probably more useful for continuum physics/fluid dynamics in the future than it is for CAD/solid mechanics/3D modeling, but currently the SDF pipeline is just kinda sitting there as dead code and not being used much.

https://github.com/yuechen-li-dev/Aetheris/tree/master/Aethe...


Replies

baigytoday at 5:45 PM

This is super interesting. Especially the high-level language > STEP/BRep lowering. Tt feels very complementary to the mesh path we're exploring and potentially the right backend when exact solids matter. I feel your SDF conclusion is useful too. It's tempting to treat it as a universal intermediate, then discover you've lost the structure you need later.

I'll dig into the repos and would compare notes afterwards.