This Claude skill empowers users to generate precise, parametric 3D models using OpenSCAD, a script-based solid CAD modeler. It bridges the gap between natural language requirements and technical 3D geometry, allowing for the automated creation of .scad files optimized for 3D printing, mechanical engineering, and rapid prototyping through Constructive Solid Geometry (CSG).

When should I use openscad?

openscad is useful in the following scenarios: • Parametric Mechanical Design: Creating adjustable parts like gears, brackets, or enclosures where dimensions are defined by variables for instant customization. • 3D Printing Preparation: Generating watertight, manifold 3D models (STL-ready) for functional prototypes, household repairs, or custom hardware components. • Algorithmic & Mathematical Modeling: Constructing complex geometric shapes and patterns derived from mathematical formulas that are difficult to draw in traditional GUI-based CAD. • 2D to 3D Transformation: Converting 2D profiles into 3D objects using linear and rotational extrusion for tasks like logo embossing or creating symmetrical mechanical parts.

name	openscad
description	Create parametric 3D models using OpenSCAD, a script-based solid CAD modeler. Use when the user asks to create 3D printable objects, parametric designs, mechanical parts, CAD models, or requests .scad files. OpenSCAD uses constructive solid geometry (CSG) and extrusion of 2D shapes to create 3D models through code.

OpenSCAD Skill

Generate OpenSCAD (.scad) files for parametric 3D modeling. OpenSCAD is a functional programming language for creating solid 3D CAD objects using CSG (Constructive Solid Geometry).

Core Concepts

OpenSCAD scripts describe geometry through:

Primitives - Basic 2D/3D shapes (cube, sphere, cylinder, circle, square, polygon)
Transformations - Position/modify objects (translate, rotate, scale, mirror, color)
Boolean Operations - Combine shapes (union, difference, intersection)
Modules - Reusable parametric components
Extrusion - Convert 2D to 3D (linear_extrude, rotate_extrude)

Workflow

Define parameters as variables at the top for easy customization
Create modules for reusable components
Build geometry using primitives and boolean operations
Use comments to explain complex sections
Set $fn for curved surface resolution (higher = smoother but slower)

Quick Reference

3D Primitives

cube([x, y, z], center=false);
cube(size, center=false);
sphere(r=radius);  // or d=diameter
cylinder(h=height, r=radius, center=false);
cylinder(h=height, r1=bottom_r, r2=top_r);  // cone
polyhedron(points=[[x,y,z],...], faces=[[p0,p1,p2],...]);

2D Primitives

square([x, y], center=false);
circle(r=radius);  // or d=diameter
polygon(points=[[x,y],...]);
text("string", size=10, font="Liberation Sans");

Transformations

translate([x, y, z]) object();
rotate([x_deg, y_deg, z_deg]) object();
rotate(a=degrees, v=[x,y,z]) object();  // rotate around axis
scale([x, y, z]) object();
mirror([x, y, z]) object();  // mirror across plane
color("red") object();
color([r, g, b, a]) object();  // 0-1 values

Boolean Operations

union() { obj1(); obj2(); }         // combine (implicit if no operator)
difference() { base(); cut1(); }    // subtract from first child
intersection() { obj1(); obj2(); }  // keep only overlap

Extrusion (2D to 3D)

linear_extrude(height=h, twist=deg, scale=s, slices=n, center=false)
    2d_shape();
rotate_extrude(angle=360, $fn=n)
    2d_shape();  // shape must be on positive X side

Control Structures

// Loops
for (i = [0:10]) translate([i*5, 0, 0]) cube(3);
for (i = [0:2:10]) ...;  // start:step:end
for (pos = [[0,0], [10,5], [5,10]]) translate(pos) sphere(2);

// Conditionals
if (condition) { ... } else { ... }
variable = condition ? value_if_true : value_if_false;

Modules and Functions

// Module (creates geometry)
module my_part(size=10, holes=true) {
    difference() {
        cube(size);
        if (holes) cylinder(h=size+1, r=size/4, center=true);
    }
}
my_part(20, holes=false);

// Function (returns value)
function circumference(r) = 2 * PI * r;

Special Variables

$fn = 100;  // fragments for full circle (overrides $fa/$fs)
$fa = 12;   // minimum angle per fragment
$fs = 2;    // minimum size per fragment
$preview    // true during F5 preview, false during F6 render

Best Practices

Parametric Design

// Define all dimensions as variables
wall_thickness = 2;
inner_diameter = 20;
height = 30;

// Derive other values
outer_diameter = inner_diameter + 2*wall_thickness;

Avoiding Rendering Issues

// Use epsilon to prevent z-fighting in boolean operations
eps = 0.01;
difference() {
    cube([10, 10, 10]);
    translate([2, 2, -eps])
        cylinder(h=10 + 2*eps, r=3);  // slightly taller than parent
}

Manifold Geometry for 3D Printing

Ensure all geometry is watertight (no gaps)
Holes must fully penetrate surfaces
Use render() to verify complex geometry
Check face orientation with F12 (Thrown Together view)

Detailed References

For complete syntax: See references/language_reference.md
For example patterns: See references/examples.md

Output

Save generated code as .scad files. Users can open in OpenSCAD for:

F5: Quick preview
F6: Full render (required before export)
Export to STL/AMF/3MF for 3D printing

openscad

When & Why to Use This Skill

Use Cases