BLbluecoconut·Jun 22, 2023Submission
Sdf – Generate 3D meshes based on SDFs
5 points · Open discussionfogleman
sdf
Python2021–2025
fogleman / sdf
sdf
Simple SDF mesh generation in Python
11Distinct people
16Mentions
0Explicit recommenders
2KGitHub stars
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What it is
Simple SDF mesh generation in Python
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Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 10:56:20 AM UTC.
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HN mentions by year16 dated mentions
Observed mentions: 2021-02-15 14:06:46 UTC to 2025-12-20 21:45:39 UTC.
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| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 6 | 1 | 5 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 5 | 2 | 3 |
What Hacker News says
4 sourcesI used to like OpenSCAD for its simple approach but then I discovered SDF-based modelling with Python made possible with this neat library: [1]. This is perfect if you are a programmer that doesn't know anything about CAD-Software.
1.: https://github.com/fogleman/sdf
In FreeCAD User Book (2019)At the moment you don't. What I'm suggesting is that you could build up a conventional BREP-based datastructure, and than use SDF to "render" it. This gives you a very clear separation between your data structure and your meshing algorithm, and as I understand it a big chunk of those "100 man years" would be in dealing with the meshing algorithm and edge cases in it.
I suspect that having a generic meshing algorithm that will always mesh your datastructure with no edge cases would significantly reduce the time needed to implement a CAD kernel. You just need an algorithm that can tell you if a given point is inside or outside of your BREP. All you really need for that is a surface that points at a given direction, and the ability to tell whether a point is under the surface or not. Define your surfaces as BREP, render them using SDF, only
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have to write one meshing algorithm.
That being said I disagree with your definition for parametric CAD. Mostly the name, I get that you're talking about BREP based CAD. That is one way to do parametric CAD, but CSG can also work, especially if you can do more advanced operations like a filleted difference or union, or blends between two shapes, or other advanced CSG operations. I don't think that CSG-based CAD is inherently worse as long as you've got the ability to do things like fillet/chamfer CSG operations.
You probably don't need to do a fillet along an edge if you can do a fillet where you subtract one object from another, something that SDFs can do easily: https://github.com/fogleman/sdf#smooth_difference
>these the the central core that understands BREP and implements the geometric operations.
I've seen people quote a good modern CAD kernal as a 100 man year project. It's probably not going to happen, maybe there's some avenue for government funding?
Alternatively Signed-Distance-Functions are pretty nice. They're not BREP, but they're a lot easier to implement, and it might be possible to shove them into a BREP-shaped hole.
Here's a signed-distance-function based CAD kernal written in a few thousand lines of python+numpy, that seems to be about as fast as openscad. Maybe faster. https://github.com/fogleman/sdf
In CAD Sketcher, free and open-source project bringing CAD like tools to Blender3d