Marsh — Backlit Modular LED Swamp Terrain Runner (28-32mm, chainable)

Marsh — a backlit modular swamp terrain runner for 28-32mm tabletop games.

WHAT IT IS A corrupted, glowing bog. A winding translucent creek runs the length of the board and GLOWS from below when a small USB LED strip is slid into a hidden channel. Minis get hummock, rock and stump footing with impassable glowing water down the middle and a bog causeway to ford it once per segment.

PRINTS IN MODULAR SEGMENTS, NO SUPPORTS, NO GLUE A real 30cm strip is longer than a 256mm plate, so the runner is built from identical clickable segments that dovetail end-to-end (2 segments of 156mm, or 4 of 78mm). One strip threads straight through all of them. The creek centre-line and the mossy bog texture are built on periodic functions, so the river, banks and ground flow continuously across every joint — a chained runner reads as one unbroken bog, not tiled boards. It also chains to a 32mm dungeon grid via the long-edge dovetails.

THE THREE PRINTED PARTS (per segment) marsh_tray.stl the light box: floor + walls + the central strip channel. Print one per segment. marsh_tray_gate.stl the SAME tray for the cable end — its end wall is gated with a ~5.5mm slot. The thin USB lead passes through, but the wide LED tape cannot, so the strip is captive and can't be tugged out. Print ONE of these (the cable end); use plain marsh_tray.stl for the rest. marsh_plate_2color.stl the terrain top. Two named solids (marsh_bog + marsh_water). Print one per segment.

TWO-COLOUR TERRAIN PLATE Slice marsh_plate_2color.stl: Import, right-click, Split to Parts. Assign a TRANSLUCENT filament (clear/coloured PETG or clear PLA — red, blue, violet or amber all read as corrupted water) to marsh_water, and your bog colour to marsh_bog. The two solids are coordinate-locked, so do NOT use Add Part with separate files. The translucency is what lets the strip glow through.

THE LIGHT — BUY THIS (user-supplied hardware) A 30 cm, 5 V USB LED strip, up to 10 mm wide. The one in the photos is the LnLED 30 cm white: self-adhesive, dimmable, touch switch on the lead, 12 LEDs, USB-powered. Any equivalent 30cm USB strip fits the channel. A COB strip (continuous emitter) gives the most even glow; a discrete-LED strip like the LnLED shows gentle bright points through the water. Slide it in light-side up, run the lead out through the gate slot, power the USB and confirm the creek glows before capping with the plates.

Print Settings

• Every part prints flat on the bed exactly as exported. No supports, no brim, no mid-print pauses. Plate is bog-side up; tray is open-side up; reeds rise vertically.

• 0.2 mm layers, 3 walls, 15% infill.

• Tray + bog: PLA is fine. Water: translucent PETG or clear PLA. Reeds print crisp in PLA, tougher in PETG.

WHAT YOU PRINT FOR A 2-SEGMENT RUNNER 1x marsh_tray_gate, 1x marsh_tray, 2x marsh_plate_2color (split-to-parts). Click the trays in a row with the gate at the cable end, lay in the strip, then drop the plates into the trays. Friction holds them; a dab of glue at two corners makes it permanent.

The full parametric OpenSCAD source is included — tune segment count, creek width and wander, ponds, rocks, reeds and the ford.