Laser cutting an ocean floor relief map

Difficulty: Medium. Time: 2–3 hours including glue-up. The saltwater cousin of the lake depth chart, built from real global ocean bathymetry.

An ocean floor map is bathymetry pointed at the sea: the continental shelf, the drop-off, and the deep water around a coastline, drawn as depth contours and cut into a layered relief. It reads like a vintage nautical chart given physical height - shallow reef water on top, the shelf stepping down through teals, and the deep navy floor at the bottom.

The Coastal Depth Chart preset is built for exactly this, using real public ocean bathymetry so coverage is global. If you want the land above the waterline in the same piece - cliffs, headlands, an island's peak - reach for the Land and Sea Relief Map instead, which carries the topography and the sea floor together.

Open the Coastal Depth Chart preset

What You'll Need

Materials

5 sheets of 3 mm laser-grade plywood for the five depth bands, or five shades of blue acrylic to let color read the depth
1 backplate sheet stained or painted deep navy (#0A3F5E in the preset)
Glue or 3M tape, weights, masking tape, optional clear epoxy for a water finish

Tools

A CO2 or diode laser cutter and a flat surface for glue-up

Step 1 - Frame a coast with a real drop-off

Open the Coastal Depth Chart preset. It loads on Australia at zoom ~4.2, the continent ringed by its surrounding seas. Search your coast and zoom so the shoreline and the water around it both fit with a margin.

The key to a good ocean piece is choosing a spot with a real drop-off. Ocean bathymetry is coarse very close to shore, so pick an island, a bay, a reef, or a stretch of steep continental shelf where the depth actually changes - Hawaii, the Channel Islands, a Caribbean reef, a fjord mouth. If the preview shows flat water with no bands, the sea floor is too uniform there; nudge to a steeper coast.

Step 2 - Tune the depth bands

Two groups, top to bottom:

Ocean depth - bathymetry on the Ocean source with the water cut as holes, five bands from shallow #CDEBEA through #9FD6DB, #6FBFCD, #3F9FBE to deep #1E6F96. Each is a plate with the deeper water removed, so the sea floor steps down. Band 1 is the visible top face: the shallowest water at the shoreline.
Backplate - #0A3F5E deep navy, the deepest water.

Unlike a lake chart there is no separate land shore plate here - the shoreline is simply the edge of band 1. If your scene includes a chunk of land you want to read as land rather than shallow water, add a solid land layer in a sand or stone tone on top, or switch to the Land and Sea Relief preset.

Step 3 - Export for the laser

Export the per-layer SVG ZIP - one plate per band plus the backplate.
Keep the inversion / holes toggle on so each band exports as a stepped plate, not a solid water shape.
Turn on small-polygon cleanup: steep shelves throw slivers along the contours.
Add a Hanger hole ring if it will hang.

Choose Your Build Method

Cut and assemble the sea floor

Cut the Backplate from your darkest material first - or use a deep teal so the deepest water glows.
Cut the five Ocean depth plates, deepest (band 5) to shallowest. Each is a full plate with a successively smaller hole; label the back of each as it comes off the bed.
Dry-fit bottom-up: backplate, band 5, 4, 3, 2, 1, checking against the on-screen chart.
Glue bottom-up, weight flat, and sand the outer edges flush so the stack reads as a solid block. 3M tape 300LSE for ply, 467/468 for acrylic.
Finish with matte clear. For the showpiece version, pour a thin layer of clear epoxy over the assembled basin so the stepped sea floor sits under glassy 'water'.

Make It Yours

Great subjects: Hawaii and its volcanic drop-offs, a Caribbean reef, the Channel Islands, a Norwegian fjord mouth, the Great Barrier Reef edge.
Cut the bands from successively darker blue acrylics so the color alone reads the depth, then top with poured epoxy.
Engrave the place name and a depth scale into a band or a separate caption plate.
Mark a dive site, a wreck, or a favorite snorkeling spot with a small icon on band 1.
Swap the teal ramp for a cold northern palette: #0B2E4F deep to #B8D8E8 shallow.
Pair it with a coastal city map of the same shoreline for a land-and-sea diptych.

Open the Coastal Depth Chart preset

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