Layout drawing
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Plate footprint
smallest → largest in this layout
Print list
| Plate | Qty | Size (mm) |
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Rigidity
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Gridfinity · 42 mm pitch · SnapClip baseplates
Give it the inside dimensions of a drawer or shelf. It returns the fewest SnapClip baseplates that fill it — and shows what one or two extra plates buys you in stiffness by breaking up the seams that let an assembled panel fold.
| Plate | Qty | Size (mm) |
|---|
Six rules, applied in order. The first is a hard result; the rest are what separate two layouts that use the same number of plates.
For a W × H grid built from plates no bigger than m, the fewest plates is
always ⌈W/m⌉ × ⌈H/m⌉ — verified by exhaustive search for every grid up to 12 × 12,
with 1 × 1 plates excluded. You cannot beat it, and staggering costs no extra plate, because each
course can split its width differently and still use the same number of pieces.
A seam crossing the whole panel is a hinge: nothing but the clips resists folding along it. Nine 5 × 5 plates in a 3 × 3 grid have four of them. Offsetting the joints course by course — the same reason brick is laid in a running bond — forces load through solid plate instead. Below six units of depth that stops working: at five units or less the run is one plate thick, and a search over every arrangement still leaves a through-seam. 252 mm is the shallowest run that can avoid one.
Slots sit at the interior 42 mm marks along a plate edge; the corners have none. So a 4 × 3 plate has 3 slots on each long side and 2 on each short side, two plates meeting over a 5-unit edge take 4 clips, and a 1 × 1 plate has no slots at all — which is why the set starts at 1 × 2.
A clip needs a slot on both sides, so both sides must be one plate running past the point. At a junction one side always changes — T-junctions and four-way junctions alike take no clip. A T is still the better joint, because the plate spanning it carries material across; a four-way carries nothing at all.
Offsetting a joint by one unit leaves two plates touching over a single unit — both its ends are junctions, so that contact gets no clip and the pair is joined by friction. Offset by two and the contact carries one clip; by three, two clips. This is the rule that decides most layouts here.
A 1 × 5 plate is a 42 mm ribbon: it warps on the bed and clips only on its two long sides. Worse, a one-unit-wide run longer than a single plate cannot be joined at all — every contact along it is one unit. Below 84 mm of width, use a single plate or nothing.
The rigidity number is a weighted index of those defects — 30% through-seams, 24% contacts left without a clip, 15% clip density along the seams, 13% plates fastened on one side only, 10% four-way junctions, 8% slivers — not a stiffness measurement. It ranks layouts against each other for the same opening; it is not comparable across different openings, and it says nothing about how well any particular clip holds.