Why generate a custom parts tray instead of downloading one?
Anyone who's organized a workshop drawer with 3D printed bins knows the problem: the model libraries are full of trays, and none of them are the right size. The drawer is 287 mm deep, the tray you found is 250 mm, and now there's a dead strip of space collecting loose screws. You can rescale a fixed STL in your slicer, but scaling a tray scales *everything* - the walls get thicker or thinner along with the footprint, and a 115% scale turns sensible 2 mm walls into wasteful 2.3 mm ones.
A parametric tray generator skips all of that. You type in the outer width, depth, and height you actually need, pick wall and base thicknesses that match your nozzle, and download an STL built to those numbers. Walls stay the thickness you chose no matter what footprint you set. If you're filling a drawer with a grid of bins, you can generate each size in under a minute and know they'll sit flush.
Choosing wall and base thickness for printable trays
For a 0.4 mm nozzle, wall thicknesses that are clean multiples of your line width slice the most predictably. A 1.6 mm wall (four perimeters) is sturdy enough for most storage trays; 1.2 mm (three perimeters) works fine for light-duty desk organizers; 2 mm and up makes sense for trays that hold heavy hardware or get tossed around in a toolbox.
For the base, 1.2 to 2 mm covers most cases. Thinner bases print faster but can flex under heavy contents; thicker bases add stiffness and a bit of weight that helps trays stay put in a drawer.
PLA is the easy default material for indoor storage trays - stiff, cheap, and dimensionally predictable. Go PETG if the tray lives somewhere warm (a garage in summer) or holds anything heavy enough to crack brittle plastic when dropped.
The optional divider
The generator can add one full-height divider across the width or depth of the tray. It's a simple way to split one bin into two compartments - screws on one side, nuts on the other - without designing a multi-compartment organizer from scratch. If you need a full grid of compartments, generating a few smaller trays usually beats one giant compartmentalized print: smaller trays print with less warping risk, and you can rearrange them later.
Runs entirely in your browser
The OpenSCAD engine that builds the model loads in your browser and runs on your device. Your dimensions and the generated geometry never touch our servers - useful if you're modeling trays around proprietary parts, and it means the tool keeps working even on a flaky connection once the engine loads.