Bluesheet

A parametric printable-object foundry. Design in a browser, slice on this laptop, print on the A1 mini in the cupboard.

http://bluesheet.local        (or http://claudespace.local:8132)

What it is

A catalogue of generators: functions from a handful of numbers to a watertight solid. Gridfinity bins, lithophanes, threaded jars, drawer dividers, terrain tiles of real places, nameplates in real font outlines, gears that actually mesh, data sculptures. Move the numbers, watch the solid rebuild, slice it, print it.

It is deliberately not CAD. There is no sketch plane and no constraint solver, because the things worth printing at home are mostly not one-off shapes — they are known shapes at your dimensions, and typing four numbers beats drawing.

Layout

js/kernel/     the geometry: mesh, 2D polygons, builders, CSG, validation, STL, fonts,
               plus scalar.js — the small helpers every generator shares
js/gen/        one file per generator; index.js is the catalogue loader
js/render/     WebGL2 viewer — solid, overhang, cross-section, gcode toolpaths
js/ui/         the interface
server/        Python: OrcaSlicer, gcode parsing, the printer, the library
tests/         node tests/run.mjs runs everything, no dependencies
gates/         the acceptance gates each part was built against
docs/design.md the visual direction

Running the tests

node tests/run.mjs            # everything
node tests/run.mjs gridfinity # one suite
node tests/mesh.test.mjs      # or directly

node tools/mesh-snapshot.mjs write   # fingerprint every generator's geometry
node tools/mesh-snapshot.mjs check   # prove a refactor changed nothing

Every generator is held to the same executable contract in tests/lib/genconform.mjs, which builds it at every parameter's minimum and maximum and asserts the result is still a watertight solid resting on the plate. A generator that only works at its defaults fails there.

The rules the code follows

Millimetres, Z up, counter-clockwise winding seen from outside, positive volume. Every generator returns a mesh already centred in X/Y with its base on z=0. No npm dependencies, no build step, no frameworks — the browser loads the modules directly and Node imports the same files for the tests.

The plate

Several objects, one print. "Add to plate" puts the current object on it with a quantity; "Show plate" packs them onto the bed (MaxRects, js/kernel/pack.js) and shows the layout that will actually print; "Slice plate" sends them as separate objects at those positions with the slicer's own arranging off. The plate lives on the server (/api/plate) and survives a reload, and every object put on it has its provenance hash registered.

Terrain of any place

The terrain generator's "Elevation you supply" option gives a place search (/api/geocode, Nominatim, cached, biased to the British Isles but not limited to them — a bare "lat, lon" works too), coordinates, a square size in km and a fetch; the server samples real Terrarium tiles and caches them under assets/elev/.

Slicing

OrcaSlicer's AppImage, driven headlessly. Four traps are documented in the vault under "Headless slicing for Bambu printers" and every one of them is load-bearing; read it before changing anything in server/slice.py. The short version: never flatten a profile, overlays need their own compatible_printers, --outputdir is prepended to --export-3mf, and vase mode fails silently. The 3mf is always re-opened and its settings asserted, because the exit code lies.

Publishing the public copy

The kernel, generators, viewer and analysis are pure browser code, so they publish as static files; the plate, slicer, printer, saved designs, Made log and geocoder need the Python server and are hidden in the public build.

node tools/build-static.mjs ../scratch-it/public/bluesheet/app

The contract is data-needs-server on every control the server backs (the build refuses to run if fewer than four are marked) and css/static.css, which hides them when <body class="is-static">. The public copy lives at https://scratch-it.co.uk/bluesheet (landing page) and /bluesheet/app/ (the workshop). Renders for the landing page come from tools/contact-sheet.mjs.

Fit clearances

Every generator's default clearance comes from one table, js/kernel/fit.js (press 0.10 · snug 0.15 · push 0.20 · slide 0.25 · loose 0.30 · board 0.35 · free 0.35 · drop 0.50 mm). MEASURED there records the one print that has confirmed a value on a named machine, material and date; until it is set the help text says the number is a guess. The Skådis gauge measures pegboard fit. free is the provisional print-in-place clearance; the planned creature joint gauge must be printed before it is calibrated.