Gridfinity Builder

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Check the fit before printing a layout ​

Use Fit Test in the toolbar to download gridfinity_fit-test.zip. It contains two identical 1×1×1u bins with stacking lips and one 2×1 open-bottom baseplate. The three objects are separated on the print bed; your current layout stays intact. Extract the ZIP to use model.3mf or the three files under stl/. The toolbar's 3MF only option downloads gridfinity_fit-test.3mf directly instead.

  1. Extract the ZIP and import model.3mf into your slicer at 100% scale. Alternatively, import the three STLs in millimetres; do not import both formats together.
  2. Check dimensions: each bin is 41.5 × 41.5 × 10.8mm; the plate is 84 × 42 × 5mm.
  3. Print all three pieces with your usual material and calibrated profile, feet down. The file supplies geometry, not printer or filament settings.
  4. Place both bins side by side in the plate, then rotate each by 90° and repeat.
  5. Stack bin A on B, then B on A. They should enter with light pressure, sit stably, and lift apart without scraping or force. Also test against a known-good external baseplate.

If a piece binds, stop before printing the full layout. Record the slicer version, material, layer height, XY compensation, first-layer expansion compensation, measured widths, and where contact occurs. Do not scale the entire bin to fix a fit: that also changes the 42mm grid pitch and magnet spacing.

The drawing's 4.4mm lip ends in a sharp tip. This app trims 0.6mm from that tip, leaving a printable crown and 3.8mm actual lip height. The 7mm height unit includes the foot but excludes the lip.

Generate from the repository ​

bash
npm run export:fit-test

The result is artifacts/gridfinity-fit-test.3mf. This generated file is ignored by Git; rerun the command after geometry changes. It uses the same bin, baseplate, mesh extraction and 3MF packaging functions as the app.

Validation boundary ​

npm test checks profile dimensions, clearance, contact at the default stacking seat, mesh connectivity, and the actual 3MF round trip. Physical fit remains unverified until these printed checks pass. See the dimension reference for socket heights and datums.