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LuaCAD – Parametric CAD Scripted in Lua

LuaCAD models solids in Lua rather than the OpenSCAD language, with operator overloading for CSG (`a + b`, `a - b`, `a * b`).It ships with a CLI and a desktop app, including a preview area and a text editor.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 one of the best scripting languages. 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 shouldn't fully replace OpenSCAD!It’s fully open source and you can find the repo here: https://github.com/ad-si/LuaCADTech 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)

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FL score

62

out of 100

Verdict

VALIDATE

medium confidence

Competition

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A Lua-based parametric CAD tool that replaces OpenSCAD's weak scripting language with a better one, targeting engineers and makers who already use OpenSCAD.

The pain

OpenSCAD users hit friction with SCAD's poor language design, inconsistent syntax, limited programming constructs, and awkward function definitions. They want to script 3D models but the language itself becomes the bottleneck, not the CAD capabilities.

The gap

No existing tool combines a mature scripting language (Lua) with parametric CAD's core strengths. OpenSCAD dominates because it's the only open-source option, not because it's good. LuaCAD fills this gap technically but hasn't proven it can convert the installed base.

Build angle

Start by converting high-value OpenSCAD users, those who write complex scripts, maintain libraries, or teach parametric modeling. Demonstrate 2-3 real projects where Lua's superiority (tables, metatables, standard library) produces cleaner, shorter code. Build BOSL2 compatibility as a migration bridge. Don't position as 'better OpenSCAD', position as 'for people who outgrew OpenSCAD's language.'

Strengths

  • Solves a real problem for an existing user base (OpenSCAD has ~100k+ active users)
  • Technical execution is solid, Rust backend, proper rendering pipeline, native BOSL2 support
  • Lua is genuinely better designed than SCAD for general programming
  • Open source removes licensing friction and builds community trust
  • CLI + desktop app covers both workflow preferences

Risks

  • OpenSCAD has 15+ years of installed base inertia; switching costs are real even if Lua is better
  • Market is small, parametric CAD users are engineers/makers, not a mass market. Total addressable users probably <50k globally
  • No clear monetization path; open source tools in this space struggle to generate revenue
  • Requires users to learn Lua; 'better language' only matters if they already know Lua or want to learn it
  • BOSL2 library is OpenSCAD's killer feature; replicating it in Rust is maintenance-heavy and may lag upstream
  • No evidence of demand beyond the creator's own preference; could be a solution looking for a problem at scale

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