How do I laser-engrave on top of a 3D carve so the laser follows the curved surface?

The technique

The hybrid CNC-carve-then-laser-detail workflow is one of the Laser Module's best tricks, and the key is the same projection checkbox the V-carve toolpath uses:

1. Carve the 3D relief first (3D Rough and Finish as usual). Leave the piece fixtured, with the same zero and the same position.
2. Set up the laser artwork vectors over the carved area.
3. Create a Laser Sketch Engraving, Laser Cut and Fill or Laser Picture toolpath and check Project toolpath onto 3D model. This option is available when a 3D model has been defined. After the toolpath is calculated, it is projected (dropped) in Z onto the surface of the model, and the depth of the original toolpath below the material surface is used as the depth below the model surface. The laser head then follows the carved surface's Z contours to keep the focal distance consistent. Without projection, the laser is focused for the original surface height and goes soft or blurry down in the carved areas.
4. Swap to the laser head and run with a laser post-processor (never a spindle post; see the post entry).

Uses: burned lettering on carved ribbons, dark accents in relief backgrounds, fine linework no bit could cut, logos on domed surfaces.

Settings notes

• No. Repeats is the number of times the same toolpath is run (it defaults to 1). It does not add extra passes unless you raise it
• Focus matters more on projected work. If your surface spans large Z changes, check your focus setup and test first. Extreme depth ranges may need splitting into zones
• Test power and speed on scrap of the same species. Carved surfaces (with exposed end grain) burn differently than flat faces

Safety

Laser plus fresh wood dust is the highest fire-risk combination in the shop. Clean the dust off the carve first, never leave it running unattended, and keep an extinguisher within reach (see the safety entry).

• Official documentation: Laser Picture (Project toolpath onto 3D Model)
• Official documentation: Laser Cut - Fill
• Learn Your CNC: Q&A Meetup, May 19 2026
• Learn Your CNC: Q&A Meetup, June 17 2025
• Official product page: Laser Module