StencilForge

StencilForge is a desktop tool for generating PCB stencil STL models from Gerber inputs.

Overview

StencilForge converts Gerber and Excellon exports into 3D STL models for PCB stencils and locator fixtures. It supports a desktop UI, configurable geometry processing, and both CadQuery and Trimesh backends.

Highlights

• Fast Gerber to STL pipeline
• CadQuery or Trimesh backend
• Stencil cutouts with configurable offsets
• Locator structure: step or wall
• VTK preview window without WebGL

Gallery

Printed stencil

UI main screen

STL preview

Quick start

1. Create a virtual environment and install dependencies: pip install -r requirements.txt
2. Install the package: pip install -e .
3. Update config/stencilforge.json as needed
4. Run:

stencilforge <gerber_dir> <output_stl>

UI

Build the UI:

cd ui-vue
npm install
npm run build

Launch the desktop UI:

stencilforge-ui

Config parameters

• paste_patterns: paste layer file patterns
• outline_patterns: board outline layer patterns
• thickness_mm: stencil thickness
• paste_offset_mm: aperture offset, negative values shrink openings
• outline_margin_mm: fallback outline margin when no outline file exists
• output_mode: holes_only or solid_with_cutouts
• model_backend: trimesh or cadquery
• locator_enabled: enable the locator structure
• locator_mode: step or wall
• locator_height_mm: locator wall height
• locator_width_mm: locator wall width
• locator_clearance_mm: locator clearance gap
• locator_step_height_mm: locator step height
• locator_step_width_mm: locator step width
• locator_open_side: open side (none/top/right/bottom/left)
• locator_open_width_mm: open width
• stl_linear_deflection: STL linear deflection in mm
• stl_angular_deflection: STL angular deflection in radians
• arc_steps: number of arc approximation steps
• curve_resolution: circle buffer resolution
• qfn_regen_enabled: enable QFN aperture regeneration
• qfn_min_feature_mm: minimum printable feature size
• qfn_confidence_threshold: confidence threshold for QFN regeneration
• qfn_max_pad_width_mm: maximum pad width considered for QFN

Conventions

• Changelog: CHANGELOG.md
• Commit messages and PR titles: Conventional Commits
• Community docs: CONTRIBUTING.md, SECURITY.md, CODE_OF_CONDUCT.md
• Issue and PR templates: .github/

License

GPL-3.0-only. See LICENSE.