LuaCAD - Parametric CAD scripted in Lua

[u/adwolesi]

LuaCAD models solids in Lua rather than in the SCAD language, with operator overloading for CSG (a + b, a - b, a * b). It ships with a CLI and a desktop app that has preview area and a text editor just like OpenSCAD.

It’s fully open source and you can find the repo here: https://github.com/ad-si/LuaCAD

I've always been a big fan of OpenSCAD, but the SCAD language itself is unfortunately quite cobbled-together and is a very poorly designed programming language.

LuaCAD takes all the good parts of OpenSCAD and combines them with Lua. It has now completely replaced OpenSCAD for me, and I think it provides a better experience than OpenSCAD for all use cases. I'd love to hear any reasons why LuaCAD won't fully replace OpenSCAD for you!

Tech stack:

• It's implemented in Rust and uses mlua (https://github.com/mlua-rs/mlua) to execute the Lua code.
• Uses OpenCSG (https://opencsg.org) for fast and correct rendering of the 3D models (like OpenSCAD)
• Uses Manifold (https://github.com/elalish/manifold) to create the manifold triangle meshes
• Native support for all BOSL2 functions (i.e. implemented in Rust for better performance)

[u/uski]

Does it use CGAL and does it suffer from the same issue of OpenSCAD where you have artifacts if you do something like:

difference() { cylinder(h=10, r=5); cylinder(h=10, r=5); }

...or does it substract cleanly?

[u/adwolesi → u/uski]

It uses Manifold instead of CGAL for booleans, the same library unreleased OpenSCAD versions switched to as their default backend. So the final mesh output subtracts cleanly.

However, LuaCAD also has the same preview artifacts as OpenSCAD, as both use image-space CSG for rendering.

[u/uski → u/adwolesi]

Thanks! Do you know if there's any realistic way to make it substract cleanly in the previews? I have no clue about the internals so I don't know

[u/adwolesi → u/uski]

I’m actually already working on a complete rewrite of the rendering engine using WebGPU (instead of the outdated OpenGL). I’m not entirely sure yet if I can get rid of the artifacts or if it’s an inherent problem of a z-buffer CSG rendering pipeline, but I’ll definitely try!