IsoGridScad

OpenSCAD library for generating isometric grid (isogrid) patterns on 2D and 3D objects.

Overview

IsoGridScad provides parametric isogrid pattern generation for both rectangular and arbitrary polygonal shapes. Isogrids are triangular lattice structures commonly used in aerospace and engineering for lightweight, high-strength panels. This library makes it easy to add these patterns to your OpenSCAD designs.

Key Features:

• ✨ Pure OpenSCAD implementation (no BOSL2 required for core functionality)
• 📐 Support for rectangles and arbitrary polygons
• 🎯 Fully parametric: control triangle size, line thickness, and extrusion depth
• 🔗 Compatible with BOSL2 attachments for easy integration
• 🎨 Generate 2D patterns or 3D extruded geometry

Installation

1. Copy isogrid.scad to your project directory
2. Include or use it in your OpenSCAD file:

use <isogrid.scad>

For BOSL2 attachment support (optional), also include:

include <BOSL2/std.scad>
use <isogrid.scad>

Quick Start

Basic Rectangular Isogrid

use <isogrid.scad>

isogrid_rect(200, 150, triangle_size=20, thickness=1, extrude=1);

3D Extruded Rectangular Isogrid

use <isogrid.scad>

isogrid_rect(200, 150, triangle_size=20, thickness=1, extrude=3);

Polygon Examples

Hexagon:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

isogrid_polygon(regular_polygon(6, 80), triangle_size=15, thickness=1, extrude=1);

Pentagon:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

isogrid_polygon(regular_polygon(5, 80), triangle_size=15, thickness=1, extrude=1);

Star Shape:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

points = 6; outer_r = 80; inner_r = 40;
star = [for (i=[0:2*points-1]) 
    let(r=(i%2==0)?outer_r:inner_r, ang=i*180/points) 
    [r*cos(ang), r*sin(ang)]];
isogrid_polygon(star, triangle_size=12, thickness=1, extrude=1);

Multiple Shapes Comparison:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

translate([-120, 0]) 
    isogrid_polygon(regular_polygon(3, 60), triangle_size=12, thickness=1, extrude=1);
translate([0, 0]) 
    isogrid_polygon(regular_polygon(6, 60), triangle_size=12, thickness=1, extrude=1);
translate([120, 0]) 
    isogrid_polygon(regular_polygon(8, 60), triangle_size=12, thickness=1, extrude=1);

Attached to 3D Objects (BOSL2)

Box with Rectangle:

include <BOSL2/std.scad>
use <isogrid.scad>

cuboid([200,150,12], anchor=CENTER) 
    attach(TOP) 
        isogrid_rect(200, 150, triangle_size=20, thickness=1.5, extrude=1);

Hexagonal Cylinder with Hexagon:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

cyl(h=12, d=160, anchor=CENTER, $fn=6)
    attach(TOP)
        isogrid_polygon(regular_polygon(6, 80), triangle_size=15, thickness=1.5, extrude=1);

API Reference

isogrid_rect()

Generate an isogrid pattern within a rectangular boundary.

Parameters:

• width - Width of the rectangle (required)
• height - Height of the rectangle (required)
• triangle_size - Side length of individual triangles (default: 10)
• thickness - Thickness of the grid lines (default: 1)
• extrude - Height to extrude in Z direction; 0 for 2D (default: 0)

Examples:

// Fine detail pattern
isogrid_rect(200, 150, triangle_size=10, thickness=0.8, extrude=1);

// Thick structural pattern
isogrid_rect(200, 150, triangle_size=20, thickness=2, extrude=3);

// Wide panel
isogrid_rect(300, 100, triangle_size=20, thickness=1, extrude=1);

Notes:

• The pattern is centered at the origin
• Triangle size determines density: smaller = finer detail
• Thickness affects line width and structural strength
• Set extrude=0 for 2D laser cutting patterns

isogrid_polygon()

Generate an isogrid pattern within an arbitrary polygon boundary.

Parameters:

• polygon - List of [x,y] points defining the polygon boundary (required)
• triangle_size - Side length of individual triangles (default: 10)
• thickness - Thickness of the grid lines (default: 1)
• extrude - Height to extrude in Z direction; 0 for 2D (default: 0)

Examples:

// Helper function for regular polygons
function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

// Pentagon
isogrid_polygon(regular_polygon(5, 80), triangle_size=15, thickness=1, extrude=1);

// Octagon
isogrid_polygon(regular_polygon(8, 80), triangle_size=15, thickness=1, extrude=1);

// Irregular polygon
custom = [[0,0], [100,20], [120,80], [80,120], [20,100], [-20,40]];
isogrid_polygon(custom, triangle_size=15, thickness=1, extrude=1);

// Star shape
points = 6; outer_r = 80; inner_r = 40;
star = [for (i=[0:2*points-1]) 
    let(r=(i%2==0)?outer_r:inner_r, ang=i*180/points) 
    [r*cos(ang), r*sin(ang)]];
isogrid_polygon(star, triangle_size=12, thickness=1, extrude=1);

Notes:

• Polygon must be a simple (non-self-intersecting) polygon
• Points should be ordered consecutively (clockwise or counter-clockwise)
• The pattern is clipped precisely to the polygon boundary
• Works with any convex or concave simple polygon

Advanced Usage

Thickness Variations

Create different structural densities by varying line thickness:

include <BOSL2/std.scad>
use <isogrid.scad>

function regular_polygon(sides, radius) =
    [for (i = [0:sides-1]) [radius * cos(i * 360 / sides), radius * sin(i * 360 / sides)]];

for(i=[0:3]) {
    translate([i*70-105, 30]) 
        isogrid_rect(60, 60, triangle_size=12, thickness=0.5+i*0.5, extrude=1);
    translate([i*70-105, -40]) 
        isogrid_polygon(regular_polygon(6,30), triangle_size=12, thickness=0.5+i*0.5, extrude=1);
}

Shown with thickness values of 0.5, 1.0, 1.5, and 2.0mm.

Density Variations

Control pattern density with triangle size:

use <isogrid.scad>

translate([-80, 0]) 
    isogrid_rect(120, 100, triangle_size=8, thickness=0.6, extrude=1);
translate([80, 0]) 
    isogrid_rect(120, 100, triangle_size=25, thickness=1.5, extrude=1);

Fine grid (left, triangle_size=8) vs coarse grid (right, triangle_size=25).

2D Patterns for Laser Cutting

Set extrude=0 to generate 2D patterns suitable for laser cutting:

// Export as 2D pattern
isogrid_rect(400, 300, triangle_size=20, thickness=1.5, extrude=0);

// Save as DXF: File → Export → Export as DXF

Design Guidelines

Choosing Parameters

Triangle Size:

• 5-10mm: Fine detail, decorative panels, small parts
• 10-20mm: General purpose, good balance of strength and weight
• 20-40mm: Structural panels, large format parts

Thickness:

• 0.5-1.0mm: Lightweight, decorative, non-structural
• 1.0-2.0mm: General purpose, light structural loads
• 2.0-4.0mm: Heavy structural loads, high strength

Extrusion Depth:

• 0-1mm: Surface detail, thin reinforcement
• 1-3mm: Moderate structural depth
• 3-10mm: Deep structural ribs, high strength

Performance Tips

1. Rendering Speed: Larger triangle sizes render faster
2. Printability: Ensure thickness ≥ 2× your nozzle diameter for 3D printing
3. Strength: Triangle size should scale with panel dimensions
4. Aspect Ratio: For rectangles, consider triangle size relative to both dimensions

Common Use Cases

• Aerospace panels: Lightweight structural panels
• Cases and enclosures: Ventilated side panels with style
• Decorative elements: Cyberpunk/sci-fi aesthetic details
• Weight reduction: Remove material while maintaining strength
• Heat dissipation: Open lattice for airflow

Testing

The isogrid_test.scad file includes comprehensive tests demonstrating all features:

// Run all tests
render_all_tests();

// Run individual tests
test_rect_basic();
test_poly_hex();
test_thickness_variation();
test_3d_attached_duo();

Technical Details

Pattern Generation

The library generates three sets of parallel lines at 0°, 60°, and -60° from horizontal, which intersect to form equilateral triangles. The spacing between parallel lines is calculated as:

h = triangle_size × √3 / 2

This ensures perfectly equilateral triangles in the resulting isogrid pattern.

Coordinate System

• Patterns are centered at the origin
• Z-axis is up for extrusion
• BOSL2 attachments follow standard anchor/spin conventions

Examples Gallery

See isogrid_test.scad for comprehensive examples including:

• Basic rectangular patterns
• Various polygon shapes (hexagon, pentagon, octagon, triangle)
• Irregular and star-shaped polygons
• Thickness and density variations
• 3D attachments to objects
• Scale progressions

License

MIT License - See LICENSE.txt for details.

Copyright (c) 2025

Contributing

Contributions welcome! Please test changes with isogrid_test.scad before submitting.

Version History

• v1.0.0: Initial release with isogrid_rect() and isogrid_polygon()