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Depth maps for laser relief engraving

A relief is only as good as its depth map — and the most common mistake is a map that is simply upside down. Here is how to read, fix and use one.

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01

The short answer

A depth map encodes height as brightness. The laser engraves deeper where the map is darker, so white parts stay at the surface and black parts become the deepest points. That matches the common height-map convention, where bright means high. Some tools export the opposite — bright for deep — and then the relief comes out like a mould. The fix is one switch: invert the depth. In Vextrify's Relief Studio that is the setting to flip the depth.

  • Darker = deeper, white = surface
  • Inside-out relief → the map uses the other convention
  • Fix: invert the depth
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02

Where depth maps come from

Depth maps can be drawn in greyscale, exported from 3D software as a height map, generated from a 3D model, or estimated from a photo. Vextrify's Relief Studio accepts greyscale images (PNG, JPG, WebP), vector shapes (SVG) that it turns into a raised or sunken form, and 3D models (STL, OBJ) that it converts into a depth map. A 2.5D shaded preview and a rotatable 3D preview show the result before anything is engraved.

  • Images: PNG, JPG, WebP
  • Shapes: SVG to a raised or sunken form
  • 3D models: STL and OBJ to a depth map
03

Why 16-bit depth maps look smoother

An 8-bit greyscale image has 256 levels; a 16-bit one has 65,536. For a photo that difference is invisible, but for a relief every level is a height step, and too few levels show up as terraces on gentle slopes. Keeping the depth map in 16-bit as long as possible — and exporting it in 16-bit where your workflow allows — keeps slopes smooth. Vextrify can export the finished depth map as a 16-bit PGM file for tools that accept it.

  • 8-bit: 256 height steps
  • 16-bit: 65,536 height steps
  • Vextrify exports 16-bit PGM depth maps
04

Depth settings come from a test strip

How deep a laser goes per pass depends on the laser source, power, speed, focus and the material — wood species alone can change it a lot. That is why Vextrify ships no relief depth values. You engrave a short test strip on your material, measure the real depth, and save it as a recipe; without that recipe the Relief Studio says the depth is not calibrated rather than inventing a number. Multi-pass strategies — roughing, smoothing and cleanup — then build on that measured depth.

  • No universal relief depth chart
  • Measure depth with a test strip on your material
  • Save it as a recipe, then plan passes

Common questions

Is white high or low in a depth map for laser engraving?

In the usual convention white is high: it stays at the surface, and black becomes the deepest point because the laser removes more material there.

Why is my laser relief inside out?

The depth map uses the opposite convention — bright for deep. Invert the depth map and the relief comes out the right way round.

Do I need a 16-bit depth map?

It helps. 16-bit has far more height steps than 8-bit, which reduces visible terracing on gentle slopes.

What settings do I use for a laser relief?

Measure them. Engrave a short test strip on your material, measure the real depth, and build the relief recipe from that — universal charts do not transfer between lasers and materials.