Posted by b-man 4 days ago
The more powerful option is something built on the open-source Open Cascade geometry kernel: FreeCAD, cadquery, or build123d. This also gives you interop with the broader CAD ecosystem by enabling you to import and export STEP files. (Your favorite LLM can advise you on or drive these options as well.)
The awful thing about OpenSCAD is that one's capabilities in it are bounded by one's fluency in using math to place or stretch cubes, spheres, and cylinders.
If you want to make a complex gear that has to mate with another gear you can do this in two ways: you can start with two discs intersecting at the right angle and then to chop out the teeth so the resulting object will be a gear and then you could subtract via a similar operation from the other disc to end up with two mating gears.
The - in my view much more effecient - alternative is to start off with just the supports as the discs and then to parametrically add the gear teeth onto the supports taking into account all of the clearances and the contact faces. This will get you much better gears because you are parametrically describing the surfaces that really matter and it will allow you to do nice things such as small fillets on everything to make the object far closer to what eventually will roll out of your manufacturing process (machining, 3D printing). It is a bit more work to define all of the parameters but the end result is much better and far less likely to have imperfections because you are generating what you want, not removing what you don't want. OpenSCAD can be used for sculpting, but that's not the best way of using it.
- Geometry: https://www.goodreads.com/book/show/58059196-make
- Trigonometry: https://www.goodreads.com/book/show/123127774-make
- Calculus: https://www.goodreads.com/book/show/61739368-make
https://www.makershed.com/products/make-physics?variant=5041...
but what made me use scad was reliability. i knew the time i put writting in vim would translate (heh) into a viable stl file i could send to manufacturing. while with both other options half the time was dealing with bugs and crashes and bad exports.
but how did i miss some convenience tools indeed. most could be solved with opensource methods (e.g. bevel, joiners with easing, threads)
OpenSCAD is super cool and my go-to for simple things, but for anything more involved than a cube or cylinder with some cutouts I tend to revert to "normal" CAD programs.
As a long-time OpenSCAD user, I don't disagree with you but would also point out that LLMs can now make it very easy to do a lot of this sort of thing while still using OpenSCAD.
I actually find Gemini/agy to be the best of the ones I've tried when it comes to working with OpenSCAD code. And I don't recommend trying to use LLMs to one-shot geometry of anything complicated, but they are great for things like "take this OpenSCAD code and generate a fillet along these edges, abstract the fillet into its own module and make it parametric so I can easily modify the radius".
Granted, selecting a few faces or edges in a GUI CAD program and clicking a button is even easier than that, but only once you've spent a lot of time learning how to use the CAD GUI (which, IMO, are nearly universally very unintuitive until you've spent a lot of time working with them).
Mango Jelly's overview of some of the biggest new features: https://www.youtube.com/watch?v=WdTyFHY-5r4
I actually still use the freecad gui because it’s cheaper but I can totally see how someone new might just wanna use the MCP.
(I recommend CQ-editor for an easy install: https://github.com/CadQuery/CQ-editor/releases/)
It's a similar idea to OpenSCAD, but embedded in Python and using a better geometry kernel. Want to fillet a box in OpenSCAD? Sure, either take the convex hull of 8 spheres, or the minkowski sum of a box and a sphere. Want to fillet a box in CadQuery? .edges().fillet()
Now I'm hearing some protests about Python, but consider this example OpenSCAD code:
x = 1;
echo(x);
x = 2;
https://github.com/yuechen-li-dev/Aetheris/
Not an OpenCascade wrapper, it's based off my own experimental BREP geometry kernel. So, fillets/chamfers work, booleans works fairly robustly, surfacing, sheet metal, etc all works decently, it exports STEP AP242 by default.
Haven't had time to get the AIs to write a more up to date documentation and polish the language server. Not the easiest thing to use right now, so, using it through Codex/Claude Code or CLI is probably the easiest way to get started.
Still working on the webUI currently, in case someone want to DIY the UI. Note that the WASM compilation path is still unoptimized and way slower than the RyuJIT C# compilation though.
I'm not going to pretend this is easy: I actually quit multiple times for this project because I ran into the same walls that everyone else ran to: arbitrary 3D boolean operations is HARD,(Surprisingly, I actually didn't have that much trouble with fillets/chamfers because I kept them pretty bounded) and the approach I've finally taken to solve it is pretty insane. Essentially, the final architecture is more like "LLVM for 3D objects" compiler stack than it is traditional BREP kernel. Would love to talk about the technical deep dives if people want to hear it.
Also, feel free to write UI wrappers around it, because I'm pretty bad at UI design myself.
It doesn’t need to be perfect on edge cases just translate back “reasonable” models.
Should be something that is fairly easy to eval etc.
I wish there was an easier way, but I've spent weeks during the course of the project working on and failing to solve a similar problem (SDF to BREP) and concluded finally that there just isn't an easier way to do this fully automated without AI.
You can ask your LLM to try it with one of the OCCT wrappers or with my thing, I think Aetheris is slightly better because we added more STEP diagnostic tools like ray query depth detection and SVG sectional view during the course of development.
The most important thing about OpenSCAD for programmers to remember is that it looks as if you are programming but really you are describing geometry and objects so things like variables and such do not quite work in the way you would expect from a programmers point of view.
I'm a novice at OpenSCAD still despite doing a bunch of small projects with it recently. Can you give an example of this happening? Most of the confusing stuff so far has been geometry breaking my brain and not some kind of scope issue.
This can lead to extremely annoying bugs because your brain is wired to read and understand this stuff sequentially rather than all at once. I've stared at some page of OpenSCAD code for a long time before realizing that it was yet another one of those footguns.
To put it another way, it's a purely functional language in a very strict way that takes some getting used to.
Some of the things developed in the project I used to modify my commercial PnP to use the Siemens feeders (Bilsef's controller board). [1]
So a project that came from our project is being used to mod my machine to make more boards for the original project :) Circle of opensource.
If you have any posts related to your mods that you can share I would like to read them to see more about what people are doing.
[1] https://www.robosprout.com/a-story-of-right-to-repair-hackin...
Check out my repos of OpenSCAD objects at https://github.com/jeffbarr/OpenSCADObjects and Truchet Tilings at https://github.com/jeffbarr/TruchetTilings .
My code kind of looks like the C that I wrote in the 1980s, with lots of braces and careful indenting -- not sure if that is a bug or a feature.
As another commenter noted, use the latest nightly build for best results.
I have built FluidCAD[1] to overcome the issues of CAD by code, less mental effort to design by providing visual guidance. Slowly it became more of a hybrid CAD experience (mouse or code driven), almost all features now can be done by mouse and the code is generated for you. It'll pick the right selection filters for you.
As noted, use the Nightly builds from: https://openscad.org/downloads.html#snapshots
When working with kids, it's well worth keeping: https://www.blockscad3d.com/editor/ in mind, or for folks who like to draw connections: https://github.com/derkork/openscad-graph-editor
Eventually, someone will note that its programming model limits variables and so forth --- for folks who want a more traditional language choice there are a number of options, notably for Python:
I'll have to add this to my backlog of experiments to try when I have unused tokens near a reset...
If you just need to tweak the dimensions in the script, or are satisfied with describing the changes to the LLM and having it modify the script, there isn't much difference in practice between a generated OpenSCAD script and a Blender python script.