Tuning the Prusa Core One

Re:Tuning the Prusa Core One by conorbergin on Monday July 07, 2025 @01:40PM (#44492788)

I think someone says this in every HN post involving CAD, but the reason FreeCAD is "buggy" and Solvespace is small and fast is Solvespace has a fraction of the power. FreeCAD uses the Open Cascade kernel, which can do complex 3d boolean and fillet operations, not having these operations severely limits the geometry you can create, and you will run into walls very quickly using Solvespace, OpenSCAD or anything else with a hand rolled geometry kernel. Even commercial projects use an off the shelf kernel, they're just difficult to write.

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Re:Tuning the Prusa Core One by Miraste on Monday July 07, 2025 @02:11PM (#44493127)

This is true, but it's not a reason to put buggy in quotes. FreeCAD is, objectively, full of bugs. Running into bugs all the time also limits what you can create. For hobbyist 3d printing purposes, Solvespace and OpenSCAD can cover the vast majority of simple single-part designs.

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Re:Tuning the Prusa Core One by conorbergin on Monday July 07, 2025 @02:56PM (#44493547)

I could not imagine trying to design a 3d part without fillets. I use Build123d mostly, and have even gone as far as using the Open Cascade library directly, but if I had to choose between FreeCAD or OpenSCAD/Solvespace I would rather work around FreeCADs jank than give up fillets.

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Re:Tuning the Prusa Core One by Miraste on Monday July 07, 2025 @03:46PM (#44493972)

Understandable, there are plugins and workarounds for fillets in OpenSCAD but they're not great.

If you're using Open Cascade through something other than FreeCAD, you may be having a better experience anyway. FreeCAD uses their own fork, which is hundreds of commits behind.

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Re:Tuning the Prusa Core One by hnuser123456 on Monday July 07, 2025 @06:51PM (#44495385)

OpenSCAD is verbose, but fillets are just a cylinder subtracted from a rectangular prism.

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Re:Tuning the Prusa Core One by Cargo4286 on Thursday July 10, 2025 @06:03PM (#44526151)

Fillets in BREP software are so much more complex than this, your statement is a huge oversimplification.

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Re:Tuning the Prusa Core One by lq9AJ8yrfs on Monday July 07, 2025 @04:40PM (#44494471)

Have you tried BOSL2? [1] Adds a lot to openscad, enough to keep me going at least. Fillets, chamfers, rounding, common parts, anchoring options, and it makes use of parent-child relationships between parts.

Not entirely perfect and some compromises, for example faceting isn't always consistent and hashtag highlighting doesn't seem quite right, but overall still it's good enough for me. The wiki on GitHub is pretty good, and with the source in hand I have had an easy time understanding what it does and tweaking it as needed.

For openscad itself, there are nightly builds with the new geometry engine, which too mostly works for me and is a huge speedup over the older CGAL engine. Renders that took minutes in CGAL now take seconds with the new engine. I like to take faceting through the roof for nicely rounded curves, but that kills CGAL apparently.

[1] https://github.com/BelfrySCAD/BOSL2

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Re:Tuning the Prusa Core One by conorbergin on Monday July 07, 2025 @05:41PM (#44494970)

I see you still have to add a fudge number to stop the faces intersecting when doing a difference boolean. I'm afraid this is still strictly worse than Build123d or any other DSL than wraps OpenCascade.

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Re:Tuning the Prusa Core One by therouwboat on Monday July 07, 2025 @06:44PM (#44495341)

I tried build123d with ocp vscode standalone and it seems interesting, but edit->run script->check browser-workflow feels annoyingly slow.

Maybe I'll try blender addon tomorrow.

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Re:Tuning the Prusa Core One by conorbergin on Monday July 07, 2025 @07:26PM (#44495592)

I've been using it for a while and I honestly don't even check the output until I'm done sometimes. I think it's more important to make good preliminary sketches and have a good idea of what you want to make, checking the output every time you change a dimension isn't that useful.

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Re:Tuning the Prusa Core One by capyba on Monday July 07, 2025 @03:52PM (#44494011)

Hard agree.

Alibre CAD has affordable permanent/monthly licenses, I recommend that as the affordable commercial option.

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Re:Tuning the Prusa Core One by mathiaspoint on Monday July 07, 2025 @02:34PM (#44493334)

FreeCAD is a mess. Especially if you're doing things like CAM.

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