Gridfinity Bin Generator

🌐 Live demo (browser-only build): https://sitnikov.github.io/gridfinity-bin-generator/

Web-based generator for Ultra Light Gridfinity Bins — Python port of HuMa_Meng's Parametric Gridfinity Ultra Light Bins SCAD source, with a Flask backend and a live Three.js 3D preview.

OpenSCAD is not used at runtime. The CSG runs in pure Python via manifold3d (a fast mesh-CSG library); a full bin generates in ~30–200 ms, fast enough to update the preview as you edit the form.

Credits & origin

This is a derivative work. All geometry decisions, dimensions, and the overall design come from the upstream SCAD source by HuMa_Meng. This repo is a port of that work to the web — nothing more.

• Original SCAD model: HuMa_Meng, Parametric Gridfinity Ultra Light Bins (CC BY-NC-SA 4.0) https://www.printables.com/model/925520-gridfinity-ultra-light-bin-generator
• Gridfinity standard: Zack Freedman (CC BY 4.0)
• Gridfinity specification (used for verification): grizzie17 (MIT) https://www.printables.com/model/417152-gridfinity-specification

If you like the model, support the original author on Printables / MakerWorld.

License

This project inherits CC BY-NC-SA 4.0 from the upstream SCAD source — see LICENSE. In short: free to share and adapt, attribution required, non-commercial only, derivative works under the same license.

Install

Python 3.10–3.12 (the build123d regression backend has no wheels on 3.13/3.14):

python3.12 -m venv venv
./venv/bin/pip install -r requirements.txt

Run

./venv/bin/python app.py
# open http://127.0.0.1:5050/

The left sidebar holds all parameters; right side is the 3D preview. Any parameter change re-generates the bin after a 150 ms debounce. Download STL saves the current configuration with a descriptive filename like gridfinity_3x2x6_w1_hr_ht_ulb_ull_lblFa-30x13_sc15.stl.

A built-in ? button in the top bar opens an in-page reference for every parameter and the filename suffix scheme.

Browser-only build (experimental)

There's also a fully client-side build under web/ — same UI, same parameters, but the geometry is generated in your browser via the WASM build of manifold-3d. No Python, no server, no cold start.

python3 -m http.server 5070 --bind 127.0.0.1 -d web
# open http://127.0.0.1:5070/

⚠️ Experimental. Compared to the Python build, the WASM manifold engine produces a slightly different triangulation (same volume and surface area to 4 decimals, ~1.5% more / differently-arranged triangles). The browser build is shipped for testing the UI and geometry pipeline; if in doubt, prefer the Python (Flask) version, which has more upstream coverage (compare_geometry.py against build123d, verify_reference.py against reference STLs).

The browser build is designed for static hosting (e.g. GitHub Pages) — it has no backend dependency. WASM and Three.js are loaded from unpkg CDNs.

Print-verification status

The geometry of both builds passes the dimensional checks below, but the maintainer has not yet run physical prints of any size to confirm real-world tolerances (foot fit on baseplates, lip stackability, magnet hole fit, label-tab strength, etc.). If you print something from this generator, treat the first print as a calibration — start with a small bin (1×1×3 or 1×2×3), check baseplate fit and lip stackability before committing to a large run, and please open an issue if you find tolerance problems.

Geometric checks that do pass (Python build):

• verify_spec.py — 24 / 24 dimensional checks against the official Gridfinity spec (within 0.001 mm).
• verify_reference.py — outer footprint + mutual stackability against the Printables 265271 reference STL set, 12 sizes from 1×1×3 to 5×5×12.
• compare_geometry.py — Δ volume < 0.4 % vs an independent build123d (NURBS / OpenCascade) implementation of the same SCAD source.

Features

• All parameters from the original SCAD: grid size (incl. half-grid), wall thickness, ultra-light base/labels, magnets, dividers, labels (Full / L / C / R, per-section), scoops.
• Extra over the original: label support density multiplier (controls the number of stiffening ribs under ultra-light label tabs).
• Settings persisted in localStorage and restored on next visit.
• Export / import of the current configuration as JSON.
• Server-side LRU cache (32 entries) — repeated requests for the same params return instantly.

Files

File	Role
gridfinity.py	manifold3d CAD engine (1:1 SCAD port)
gridfinity_b123.py	optional build123d backend — regression only
app.py	Flask: GET /, POST /generate, LRU cache
templates/index.html	Form + Three.js viewer + help modal (Flask)
web/index.html + web/gridfinity.js	Browser-only build (manifold-3d WASM, experimental)
verify_spec.py	Conformance check vs the official Gridfinity spec
verify_reference.py	Stackability check vs reference STLs (*)
compare_geometry.py	manifold3d ↔ build123d regression
UltraLightGridfinityBins.scad	upstream SCAD (kept for side-by-side review)
LICENSE	CC BY-NC-SA 4.0

(*) Reference STL set is not bundled in this repo to avoid redistributing files of unclear license. To run verify_reference.py, download the ZIP from Printables 265271 — Gridfinity Lite Economical Plain Storage Bins and unpack it into gridfinity-lite-economical-plain-storage-bins-model_files/ at the repo root.

CLI

./venv/bin/python gridfinity.py /tmp/my_bin.stl

Uses defaults (1×2×3, ultra-light, no magnets/dividers/labels/scoop). For non-default parameters, import GridfinityParams and call export(p, path).

Architecture notes

The engine is a literal port of the SCAD source — no design changes, no optimisation tricks. Each construct maps directly:

OpenSCAD	manifold3d
cube, cylinder	Manifold.cube, Manifold.cylinder
translate, mirror	.translate(), .mirror()
union / difference	+ / -
hull() { 4 cylinders }	Manifold.batch_hull([…])

If you fix a bug or add a feature, please follow this 1:1 style — find the equivalent in the SCAD source first, then translate it to the same primitives.

Contributing

Issues and PRs welcome. By contributing you agree your changes are released under CC BY-NC-SA 4.0 (the project's license).

Ground rules:

• Do not introduce features that don't exist in the upstream SCAD without explicit need — this is a port, not a fork in spirit.
• Run verify_spec.py before sending geometry-touching changes (24/24 must stay green).