parametric-box/README.md

Wargame Accessory Box & Dice Tray

A parametric OpenSCAD box for carrying tabletop wargaming accessories. Four printable parts:

Part	Purpose
box	Open tray. With the insert removed it doubles as a dice tray.
lid	Fully detachable lid, held shut by snap latches hinged on filament pins (or a classic friction fit).
latch	One-piece snap latch — print two per latch position.
insert	Removable compartment tray for tokens, measuring tapes, etc.

Quick start

Open wargame_box.scad in OpenSCAD and set the three total_* values to the free space in your backpack — they are outer dimensions and total_z already includes the closed lid, so the printed result fits the measured space exactly.

Pick what to render with the part variable (or the customizer): assembly (exploded preview), box, lid, insert, latch, print.

Or export everything from the command line:

make            # exports stl/box.stl, stl/lid.stl, stl/insert.stl, stl/latch.stl

The latch lid

By default (lid_style = "latch") the lid is held shut by snap latches that hinge on short pieces of filament:

• The lid carries pairs of lugs along its front and back edges.
• Each latch is a single printed part with a pivot barrel that fits between a lug pair. Its window snaps over a chamfered catch bar on the box wall; pull the flared tip outward to open.
• To assemble one latch: cut a ~23 mm piece of 1.75 mm filament, slide it through lug → latch barrel → lug, and fix it with a drop of glue on the outer lug holes only — the lug holes are sized tight and the barrel hole loose, so the latch keeps pivoting freely. Trim the pin flush.

Tuning knobs (all per side unless noted):

• latches_per_side — how many latches on each long wall (default 2, evenly spread).
• catch_proud — how far the catch bar sticks out = how hard the snap is (default 1.4 mm).
• latch_play — vertical play between latch and catch bar (default 0.1 mm). Use a small negative value to preload the lid shut.
• filament_d — hinge pin diameter, in case you want to use 2.85 mm filament or a piece of wire instead.

Note: lugs and latches stick out about 7 mm beyond the box on the front and back, so allow total_y + 14 of space in the backpack. With latches doing the holding, a looser lip (lid_clearance around 0.3–0.4) makes the lid pleasant to take off.

Prefer the original hinge-free push-fit lid? Set lid_style = "friction" and you get the old behaviour, including the thumb grooves for prying the lid off.

Configuring the insert layout

Compartments are defined by the layout list, one entry per row (front to back):

layout = [
    [1.0, [1, 1, 1, 1]],   // front row: 4 equal token bins
    [1.0, [2, 1, 1]],      // middle row: 1 double-width + 2 small
    [0.8, [1]]             // back row: full-width slot (tapes etc.)
];

• The first number is the row depth weight.
• The list is the column width weights within that row.

Weights are relative, so the layout always fills the insert exactly no matter what box size you choose. A row weight of 2 is twice as deep as a row of weight 1; a column weight of 2 is twice as wide as 1.

To print a second insert variant (e.g. for a different game system), just change layout, re-export, and swap inserts as needed. Two half-height stacked inserts are possible too: set insert_h_override to about half of the automatic height and print two with different layouts.

How the parts work together

• The lid is a flat plate with a lip that plugs into the box opening. With the latch lid the lip just aligns the lid (and keeps tokens in their compartments); with lid_style = "friction" it carries the whole fit. lid_clearance (default 0.2 mm per side) controls how snug it is — print a test fit and adjust for your printer/material. In friction mode, shallow thumb grooves on the box's front and back walls let you pry the lid off; they do not pierce the wall, so the dice tray stays fully closed.
• The insert sits below the lid's lip, so the lip also keeps loose tokens from jumping compartments in the bag. Finger notches on its short walls let you lift it straight out; then the empty box is your dice tray. tray_chamfer puts a 45° bevel around the floor edges so dice don't lodge in the corners.

Printing notes

• No supports needed for any part. Print all parts flat side down (the lid prints plate-down, lip and lugs up). The latch prints standing on its flat side — that gives a clean pivot hole and puts the layer lines along the strip, where the snap stress is.
• PLA or PETG, 2–3 perimeters, ~10 % infill (the parts are mostly walls).
• If the lid is too tight/loose, tune lid_clearance in steps of 0.05 mm. Same for the insert with insert_clearance (looser is fine there — it just needs to drop in and lift out easily).
• A piece of felt glued into the box floor makes dice rolling quieter; if you plan this, add the felt thickness to nothing — the inner depth is generous — but you may want tray_chamfer = 0 for a flat floor.