# Openscad 3d Modeling > OpenSCAD-based 3D modeling for programmatic generation of solid CAD models suitable for 3D printing. Use when generating mechanical parts, parametric designs, functional prototypes, geometric shapes, or any 3D printable models. Handles Constructive Solid Geometry (CSG) operations, primitive shapes (cube, sphere, cylinder, polyhedron), transformations (translate, rotate, scale), and export to STL/3MF formats. Ideal for AI-driven model generation where scripts are created and rendered headless. Use when this capability is needed. - Skill: `tomevault-io/openscad-3d-modeling` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/openscad-3d-modeling` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/openscad-3d-modeling/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/openscad-3d-modeling --- # OpenSCAD 3D Modeling ## Overview OpenSCAD is a programmer's solid 3D CAD modeller that uses scripts to generate 3D models. Unlike interactive 3D tools, OpenSCAD models are described declaratively in code, making them ideal for AI-driven generation. Models are built from primitives (cube, sphere, cylinder) combined with boolean operations (union, difference, intersection) and transformed (translate, rotate, scale). ### Key Concepts **Constructive Solid Geometry (CSG)**: Combine simple shapes into complex models using boolean operations - `union()` - Combine multiple shapes into one - `difference()` - Subtract shapes from each other - `intersection()` - Keep only overlapping regions **Primitives**: Basic building blocks - `cube(size=[x,y,z])` - Rectangular box - `sphere(r=radius)` - Sphere - `cylinder(h=height, r=radius)` - Cylinder - `polyhedron(points, faces)` - Arbitrary shape **Transformations**: Position and orient shapes - `translate([x,y,z])` - Move shape - `rotate([x,y,z])` - Rotate around axes - `scale([x,y,z])` - Resize shape - `resize([x,y,z])` - Resize to specific dimensions ### Render Pipeline ``` OpenSCAD Script (.scad) ↓ Preview (Fast, GPU, approximate) ↓ Full Render (Slow, CPU, exact) ↓ Export (STL, 3MF, OFF, DXF) ``` ## Workflow Decision Tree ``` User Request ↓ Is this for 3D printing? ├── YES → Generate OpenSCAD script │ ↓ │ Validate script syntax │ ↓ │ Render preview (openscad -o preview.png input.scad) │ ↓ │ Full render for export (openscad -o output.stl input.scad) │ ↓ │ Return .stl + .scad + preview image │ └── NO → May need Three.js (different skill) or clarify user intent ``` ## Step 1: Generate OpenSCAD Script ### Syntax Basics ```openscad // Resolution control for 3D printing quality $fa = 1; // Minimum angle (degrees) $fs = 0.4; // Minimum size (mm) // Simple box cube([20, 20, 10]); // Sphere sphere(r=10); // Cylinder cylinder(h=20, r=5); ``` ### Combine Shapes with CSG ```openscad // Union - combine shapes union() { cube([20, 10, 10]); translate([20, 0, 0]) cube([10, 10, 10]); } // Difference - subtract shapes difference() { cube([20, 20, 10]); translate([5, 5, -1]) cylinder(h=12, r=3); } // Intersection - keep overlap intersection() { cube([20, 20, 20]); sphere(r=15); } ``` ### Transformations ```openscad // Translate translate([10, 10, 0]) cube([10, 10, 10]); // Rotate rotate([90, 0, 0]) cylinder(h=20, r=5); // Scale scale([2, 1, 1]) sphere(r=10); // Chain transformations translate([10, 0, 0]) rotate([0, 90, 0]) cylinder(h=10, r=5); ``` ### Modules for Reusability ```openscad module gear(teeth=8, radius=20, thickness=5) { union() { cylinder(h=thickness, r=radius); for (i = [0:teeth-1]) { rotate([0, 0, i * 360/teeth]) translate([radius, 0, 0]) cube([5, 3, thickness], center=true); } } } // Use module gear(teeth=12, radius=15, thickness=3); ``` ## Step 2: Validate Script ### Common Validation Checks 1. **Syntax errors**: Missing semicolons, unmatched brackets 2. **Valid geometry**: Manifold edges, no self-intersections 3. **Overlap tolerance**: Use 0.001mm overlap between touching surfaces ### Validation Script Use `scripts/validate_openscad.py` to check: ```bash python3 scripts/validate_openscad.py model.scad ``` Returns: - ✅ Valid: Script compiles successfully - ❌ Error: Syntax error message ## Step 3: Render Model ### Quick Preview (for iteration) ```bash openscad -o preview.png input.scad ``` - Fast GPU rendering - Good for checking geometry - Not export-quality ### Full Render (for export) ```bash openscad -o output.stl input.scad ``` - Slow CPU rendering with CGAL - Produces exact geometry - Ready for 3D printing ### Export Formats | Format | Use Case | Command | |--------|----------|---------| | STL | 3D printing (most common) | `openscad -o model.stl input.scad` | | 3MF | Modern 3D printing (metadata + color) | `openscad -o model.3mf input.scad` | | OFF | Simple ASCII format | `openscad -o model.off input.scad` | | DXF | 2D drawings (laser cutter) | `openscad -o model.dxf input.scad` | | PNG | Preview image | `openscad -o model.png input.scad` | ## Best Practices ### 1. Resolution Control Always set resolution variables at the top: ```openscad $fa = 1; // Minimum angle: 1 degree $fs = 0.4; // Minimum size: 0.4mm ``` - `$fa`: Minimum angle for circle segments (lower = smoother) - `$fs`: Minimum segment size (lower = finer detail) - Default values may create faceted curves ### 2. Overlap Tolerance When shapes touch, ensure small overlap (0.001mm): ```openscad difference() { cube([20, 20, 10]); translate([5, 5, -0.001]) // Small overlap cylinder(h=10.002, r=3); } ``` ### 3. Use Modules Encapsulate complex geometry in modules: ```openscad module bolt_hole(length, diameter) { cylinder(h=length, r=diameter/2); } // Use multiple times difference() { plate(); translate([10, 10, 0]) bolt_hole(10, 5); translate([20, 10, 0]) bolt_hole(10, 5); } ``` ### 4. Parameterize Design Make designs configurable: ```openscad module box(width=50, depth=50, height=20, wall_thick=2) { difference() { cube([width, depth, height]); translate([wall_thick, wall_thick, wall_thick]) cube([width-2*wall_thick, depth-2*wall_thick, height]); } } // Use with parameters box(width=60, depth=40, height=15, wall_thick=3); ``` ## Common Patterns ### Hollow Box ```openscad module hollow_box(width, depth, height, wall_thick) { difference() { cube([width, depth, height]); translate([wall_thick, wall_thick, wall_thick]) cube([width-2*wall_thick, depth-2*wall_thick, height-wall_thick]); } } ``` ### Fillet (Rounded Edge) ```openscad module fillet(radius, length) { difference() { cube([radius, radius, length]); translate([radius, radius, -1]) cylinder(h=length+2, r=radius); } } ``` ### Bracket ```openscad module bracket(width=40, height=30, thickness=5, hole_diameter=8) { difference() { // L-shape union() { cube([width, thickness, thickness]); cube([thickness, height, thickness]); } // Holes translate([width/2, -1, thickness/2]) rotate([-90, 0, 0]) cylinder(h=thickness+2, r=hole_diameter/2); translate([-1, height/2, thickness/2]) rotate([0, 90, 0]) cylinder(h=thickness+2, r=hole_diameter/2); } } ``` ### Gear ```openscad module gear(teeth=8, radius=20, thickness=5, hole_diameter=5) { difference() { union() { // Main body cylinder(h=thickness, r=radius); // Teeth for (i = [0:teeth-1]) { rotate([0, 0, i * 360/teeth]) translate([radius, 0, 0]) cube([radius/2, radius/teeth*2, thickness], center=true); } } // Center hole cylinder(h=thickness+1, r=hole_diameter/2, center=true); } } ``` ## Resources ### scripts/ - **validate_openscad.py**: Validate OpenSCAD scripts for syntax errors - Use when checking generated scripts before rendering ### references/ - **primitives.md**: Complete list of OpenSCAD primitives with examples - **transformations.md**: Transformation operations and patterns - **modules.md**: Common reusable modules and patterns - **export_formats.md**: Export format specifications and use cases ### assets/ - **templates/simple_box.scad**: Basic box template - **templates/mechanical_part.scad**: Mechanical part template - **templates/parametric_design.scad**: Parametric design template - **templates/assembly.scad**: Assembly template ## Resources See [references/primitives.md](references/primitives.md) for complete primitive reference. See [references/modules.md](references/modules.md) for reusable module patterns. See [assets/templates/](assets/templates/) for starting templates. Use `scripts/validate_openscad.py` to validate scripts before rendering. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/co-labs-co) — claim your Tome and manage your conversions.