OpenSCAD Cut List Generation (woodworkers-lib)

Generate accurate cut lists from OpenSCAD furniture designs using the woodworkers-lib library's automatic ECHO output for panel dimensions and edge banding specifications.

Quick Start

include <woodworkers-lib/std.scad>

cabinet = [800, 400, 1200];  // width × depth × height

planeLeft(cabinet, f=-1, t=-1, b=-1, af=4);      // Side panel with front edge band
planeRight(cabinet, f=-1, t=-1, b=-1, af=4);     // Side panel with front edge band
planeTop(cabinet, f=-1, af=4, al=4, ar=4);       // Top with 3 edge bands
planeBottom(cabinet, f=-1, af=4, al=4, ar=4);    // Bottom with 3 edge bands
planeBack(cabinet, thick=4);                      // Thin back panel (fiberboard)

Render to see cut list:

openscad cabinet.scad 2>&1 | grep "ECHO: \"plane"

Output:

ECHO: "plane (left):   18 × 378 × 1164(4)"
ECHO: "plane (right):  18 × 378 × 1164(4)"
ECHO: "plane (top):    782(4,4) × 378(4) × 18"
ECHO: "plane (bottom): 782(4,4) × 378(4) × 18"
ECHO: "plane (back):   800 × 4 × 1200"

Interpretation:

• 18 × 378 × 1164(4) = 18mm thick panel, 378mm × 1164mm, with 4mm edge band on one edge
• 782(4,4) × 378(4) × 18 = 18mm thick panel, 782mm × 378mm, with edge bands on 3 edges (4mm each)

Usage

See Core Workflow below for complete step-by-step process.

Core Workflow

1. Design Furniture with Plane Modules

Define furniture dimensions:

include <woodworkers-lib/std.scad>

thick = 18;  // Override default panel thickness if needed
rounding = 2;  // Edge rounding radius

wardrobe = [1000, 400, 1200];  // W×D×H in mm

Decompose into panels using plane modules:

Example: Basic cabinet frame

translate([10, 0, 0]) {
    planeLeft(wardrobe, f=-1, t=-1, b=-1);
    planeRight(wardrobe, f=-1, t=-1, b=-1);
    planeTop(wardrobe, f=-1);
    planeBottom(wardrobe, f=-1);
    planeBack(wardrobe, thick=4);  // Thin fiberboard back
}

Add internal components (shelves, dividers):

// Shelf at 400mm height
translate([0, 0, 400])
    planeBottom(wardrobe, l=-1, r=-1, f=-1);

// Vertical divider at 500mm from left
translate([500, 0, 0])
    planeLeft(wardrobe, f=-1, t=-1, b=-1);

2. Understand Parameter System

The woodworkers-lib uses three parameter types:

A. Thickness-Relative Increments (multiplied by thick)

Parameters: l, r, t, b, f, B

Use case: Fit panels inside frames without manual calculation.

// Side panels fit between top and bottom (-1 on top, -1 on bottom)
planeLeft(cabinet, t=-1, b=-1);

// Top panel extends over sides (no reduction)
planeTop(cabinet);

B. Absolute Increments (exact mm values)

Parameters: ll, rr, tt, bb, ff, BB

Use case: Precise adjustments, gaps, door clearances.

// Door panel 4mm narrower on each side for clearance
planeFront(cabinet, ll=-4, rr=-4);

// Extend shelf 10mm past frame edge
planeBottom(cabinet, ff=10);

C. ABS Edge Banding (visualized and reported)

Parameters: al, ar, at, ab, af, aB

Use case: Specify which edges need edge banding tape (typically front-facing edges).

// Top panel with edge band on front, left, and right
planeTop(wardrobe, f=-1, af=4, al=4, ar=4);

// Output: "plane (top): 992(4) × 378(4,4) × 18"
//                           ^        ^^
//                        front    left,right

Parameter Interaction:

Edge banding affects absolute increments automatically:

planeLeft(wardrobe, f=-1, ff=10, af=4);
// Effective front dimension: base + (-1×thick) + 10 - 4
// The 'af=4' reduces effective dimension by 4mm

3. Capture Cut List Output

Method 1: OpenSCAD GUI Console

1. Open .scad file in OpenSCAD
2. Press F5 (Preview) or F6 (Render)
3. View Console window (bottom panel)
4. Copy ECHO lines starting with "plane (

Method 2: Command Line (Recommended)

# Capture all ECHO output
openscad --render furniture.scad 2>&1 | grep "ECHO: \"plane"

# Save to file
openscad --render furniture.scad 2>&1 | grep "ECHO: \"plane" > cutlist.txt

# Count unique panels
openscad --render furniture.scad 2>&1 | grep "ECHO: \"plane" | sort | uniq -c

Method 3: Script Integration

See scripts/extract_cutlist.py for automated extraction with CSV export.

4. Parse ECHO Output

Output Format:

ECHO: "plane (FACE):  DIM1(edges) × DIM2(edges) × THICK"

Parsing Rules:

1. Three dimensions always present: DIM1 × DIM2 × THICK
2. Thickness is smallest dimension (typically 18mm, 16mm, or 4mm)
3. Edge bands in parentheses after dimension: 782(4) = 782mm with one 4mm edge
4. Multiple edges separated by commas: 378(4,4) = 378mm with two 4mm edges
5. Panel orientation from face name: (left), (right), (top), (bottom), (front), (back)

Examples:

Identifying edge band locations:

The edge band notation appears on the dimension where the edge is applied:

• 782(4,4) × 378(4) × 18 = edges on 782mm side (2 edges) + 378mm side (1 edge) = 3 total edges
• For rectangular panels, this typically means 3 visible edges (4th hidden against wall/back)

5. Export for Optimization Tools

Manual CSV Creation:

Create spreadsheet with these columns:

Part Name, Width, Height, Thickness, Quantity, Edge1, Edge2, Edge3, Edge4
Left Side, 378, 1164, 18, 2, 4, 0, 0, 0
Top Panel, 782, 378, 18, 1, 4, 4, 4, 0
Back Panel, 1000, 1200, 4, 1, 0, 0, 0, 0

Using Utility Script:

# Generate CSV from SCAD file
python3 scripts/extract_cutlist.py furniture.scad -o cutlist.csv

# Import to CutListOptimizer.com or optiCutter.com

Upload to CutListOptimizer:

1. Visit cutlistoptimizer.com
2. Click "Import" → "CSV File"
3. Upload generated CSV
4. Set sheet dimensions (e.g., 2440×1220mm for standard plywood)
5. Set blade thickness (typically 3mm for table saw)
6. Click "Optimize"

Output formats supported:

• CSV (comma-separated)
• TSV (tab-separated)
• JSON (for programmatic integration)

See examples/cutlist_export.csv for reference format.

Resources

examples/

• wardrobe_example.scad - Complete wardrobe design from library README with annotations
• cabinet_variations.scad - Different cabinet configurations and cut list outputs
• cutlist_export.csv - Sample CSV format for CutListOptimizer import

scripts/

• extract_cutlist.py - Python script to automate ECHO parsing and CSV generation
  • Usage: python3 extract_cutlist.py input.scad -o cutlist.csv
• validate_cutlist.py - Checks for duplicate panels and calculates total material
  • Usage: python3 validate_cutlist.py cutlist.csv

references/

• parameter_reference.md - Complete parameter documentation with visual diagrams
• edge_banding_guide.md - Edge banding best practices and notation examples

Expected Outcomes

Successful Cut List Generation:

✅ Cut List Generated Successfully

Source: workshop/cabinets/workbench-cabinet.scad
Panels found: 15
Unique panels: 8

Panel breakdown:
  - 18mm panels: 12 (total area: 4.2 m²)
  - 4mm panels: 3 (total area: 1.8 m²)

Edge banding required:
  - 4mm ABS tape: 18 edges (total length: 24.5m)

Output saved: cutlist.csv
Ready for import to CutListOptimizer

Next steps:
1. Upload cutlist.csv to optimization tool
2. Set sheet size (2440×1220mm standard)
3. Generate cutting diagrams
4. Calculate material cost

Validation Warnings:

⚠️  Validation Warnings

Potential issues detected:
1. Duplicate panel: "378 × 1164 × 18" appears 4 times
   → Confirm quantity is correct (not accidental duplication)

2. Unusual thickness: "12mm" found (expected 18mm, 16mm, or 4mm)
   → Verify panel specification

3. Large panel: "1200 × 2400 × 18" exceeds standard sheet size
   → May require joining or special order

4. Missing edge bands: Panel "front (door)" has no ABS parameters
   → Add af/al/ar/at parameters if visible edge

Review design before ordering materials.

Requirements

Software:

• OpenSCAD 2021.01+ (tested with 2025.12.14 development snapshot)
• woodworkers-lib installed: ~/Documents/OpenSCAD/libraries/woodworkers-lib/
• (Optional) Python 3.8+ for utility scripts

Installation:

cd ~/Documents/OpenSCAD/libraries/
git clone https://github.com/fxdave/woodworkers-lib.git

Knowledge:

• Basic OpenSCAD syntax (modules, translate, include)
• Understanding of furniture construction (frames, panels, shelves)
• Familiarity with plywood/MDF sheet goods (standard thicknesses: 18mm, 16mm, 12mm, 4mm)

Red Flags to Avoid

• Using cube() instead of plane*() modules (no cut list output)
• Forgetting -1 thickness adjustments for nested panels (dimensions wrong)
• Mixing absolute increments and thickness increments incorrectly
• Not accounting for edge banding thickness in tight-fit joints
• Ignoring duplicate panel warnings (over-ordering material)
• Using non-standard thicknesses without supplier confirmation
• Exceeding standard sheet size (2440×1220mm) without planning joins
• Missing edge bands on visible edges (unprofessional finish)
• Not validating cut list against 3D model before ordering
• Capturing ECHO output from old/stale render (dimensions outdated)

Notes

Parameter Naming:

• f = front, B = Back (capital B to distinguish from b = bottom)
• Single letter = thickness-relative, double letter = absolute (e.g., l vs ll)
• a prefix = ABS edge banding (e.g., al = ABS left)

Edge Banding Best Practices:

• Apply to all visible front-facing edges
• Skip back edges (against walls) and hidden internal edges
• Standard widths: 19mm, 22mm, 40mm (4mm thickness for ECHO notation means ABS tape thickness)
• Use matching wood grain direction for professional appearance

Material Standard Thicknesses:

• Plywood/MDF: 18mm (most common), 16mm, 12mm, 9mm, 6mm
• Fiberboard (backs): 4mm, 3mm
• Verify supplier availability before designing with non-standard thickness

Performance:

• woodworkers-lib renders fast (uses basic cubes with hull() rounding)
• Complex furniture (20+ panels): <5 seconds preview, <30 seconds full render
• ECHO output generation: instant (happens during preview/render)

Troubleshooting:

• If no ECHO output: Check include <woodworkers-lib/std.scad> is present
• If dimensions wrong: Verify thick=18 matches your material thickness
• If edge bands missing: Ensure a* parameters specified on correct plane module
• If panels overlap: Check thickness-relative parameters (l, r, t, b, f, B)