truescad

▶ Open TrueScad in your browser

TrueScad is a Lua-scripted CAD tool similar to OpenSCAD, running entirely in the browser as a WebAssembly app. Like ImplicitCAD, it uses implicit functions to represent geometry, offering precise surfaces and smooth rounded CSG.

Using the app

Write a Lua script in the left panel using the primitives below, then:

• Run — evaluates the script and shows a ray-marched preview
• Mesh — tessellates the geometry and shows a 3D mesh (drag to rotate)
• Export STL — downloads the tessellated mesh as an STL file

Drag on the preview canvas to rotate (left button) or pan (right button).

Lua API

Primitives

Sphere(radius)
Box(x, y, z, smooth?)           -- smooth rounds the edges
Cylinder({l=length, r=radius, s=smooth?})
Cylinder({l=length, r1=r1, r2=r2, s=smooth?})  -- tapered
iCylinder(radius)               -- infinite cylinder
iCone(slope)                    -- infinite cone
PlaneX(d)  PlaneNegX(d)         -- half-spaces
PlaneY(d)  PlaneNegY(d)
PlaneZ(d)  PlaneNegZ(d)
PlaneHessian({nx,ny,nz}, p)
Plane3Points({x,y,z}, {x,y,z}, {x,y,z})

Boolean operations

Union({obj, ...}, smooth?)
Intersection({obj, ...}, smooth?)
Difference({obj, ...}, smooth?)  -- first minus the rest

Transformations (method syntax)

obj:translate(x, y, z)
obj:rotate(x, y, z)      -- Euler angles in radians
obj:scale(x, y, z)
obj:clone()

Deformations

Bend(obj, width)
Twist(obj, height)

Output

build(obj)   -- sets the object to render/export
print(...)   -- output appears in the log panel

Example

cube   = Box(1, 1, 1, 0.3)
sphere = Sphere(0.5)
result = Difference({cube, sphere}, 0.3)
result = result:scale(15, 15, 15)
build(result)

Development

Prerequisites

• Rust (stable)
• wasm-pack — cargo install wasm-pack
• Node.js 18+

Build and run locally

# Install JS dependencies (once)
npm install

# Build the Rust WASM module
wasm-pack build --target web

# Bundle the frontend and start the dev server
npm run serve
# → http://localhost:8080

After changing Rust code, re-run wasm-pack build --target web and refresh the browser. After changing JS/CSS in web/, the dev server rebuilds automatically.

Run Rust tests

cargo test

Production build

wasm-pack build --target web --release
npm run build:release
# Output in dist/

Architecture

• src/luascad.rs — Lua scripting engine (piccolo), exposes all geometry primitives
• src/shader.rs — builds the GLSL fragment shader for GPU ray-marching
• src/lib.rs — wasm-bindgen API surface (eval, render, rotate, pan, tessellate)
• web/ — vanilla JS frontend: CodeMirror 6 editor, Three.js mesh view
• build.mjs / serve.mjs — esbuild-based build and dev server