A CNC relief carving is all shape. Put it under a light from the side and it comes alive; hang it on a flat-lit wall and half of that depth disappears. Burning a little tone into it with a laser brings the depth back: a darkened background floor, a scorched outline, a few shadows where the carving already wants them. The piece reads from across a room instead of only up close.
The hard part is not the burn. It is putting the burn in exactly the right place on a piece that is already carved, sitting wherever you happened to set it on the laser bed. This guide covers how to do that, whether your laser has a camera or not, using a real customer job as the worked example.
In this guide
- Why lining up a burn on a carving is hard
- A real job, start to finish
- Two routes: with a laser camera, or without one
- Route one: lining up in the camera view
- Route two: no camera, and why that is fine
- If you own a WeCreat laser
- What to burn onto a carving
- Focus, power and the first test
- CNC Match in Laser Studio
- Questions people ask
Why lining up a burn on a carving is hard
On a flat blank you can put the design anywhere; the laser starts wherever you tell it. On a carving the design already exists in the wood, and the burn has to land on top of it within a millimetre or so, or the shading sits beside the shape it was meant to deepen. Three things get in the way.
- You do not know exactly where the piece is. You set the board down by eye. It is a few millimetres off and a degree or two turned, and on a carving that shows.
- Laser cameras are not perfectly accurate. A camera looks at the bed from an angle through a wide lens. Even after calibration the picture is slightly stretched towards the edges, and a raised carving adds its own parallax.
- The file and the carving must be the same size. The burn has to be scaled to the carved footprint exactly, not to the board, and a design scaled by 2 percent looks fine in the middle and wrong at the edges.
The good news is that if the burn image and the carving come from the same source, they share one outline. Our relief STL files ship with a matching PNG made from the same height map, so line the PNG up with the carving and everything you add lands where it should.
A real job, start to finish
These photographs are from Joseph of Almost Forgotten, who carved one of our relief files on his CNC and then burned it on his laser. He tested our alignment tool as it was being built, and two of the features in it today came from his suggestions.
Two routes: with a laser camera, or without one
How you line the burn up depends on whether your laser software can show you a live camera picture of the bed.
| Your setup | How you line up | Best for |
|---|---|---|
| Software with a bed camera | Drag an outline over the carving in the camera view | Quick one-offs |
| No camera available | Type the exact position, or use registration marks or a jig | Precision and repeat orders |
Both routes start the same way: a photo of the carved piece on the bed, and a burn file that is already the exact size of the carving.
Route one: lining up in the camera view
The trick that makes camera alignment easy is not to line up the burn file itself. Line up a ghost: a second file in exactly the same frame as the burn, containing only the carving's outline, a border and a centre cross. You can see the wood straight through it.
- Import the burn file and the ghost into your laser software.
- Centre them on each other and group them, so they move as one.
- Put the ghost on its own layer and switch that layer's output off. It is a guide, never a burn.
- Turn the camera view on and drag the group until the ghost outline sits on the carving. Burn.
One rule if you rotate the group: use a grayscale burn file and let the laser software dither it. Rotating an image that is already dithered smears its dots and softens the burn.
Route two: no camera, and why that is fine
A camera's only job here is to tell you where the carving is. If you work that out from a photo instead, you do not need a live camera at all, and you get a number you can type rather than a position you judge by eye.
- Position numbers. Photograph the bed with the piece on it, straighten the photo against the bed's four corners, and line the design up on the photo. You get the X and Y of the burn from the bed corner and its angle. Type those into your laser software with the centre of the burn file as the reference point.
- Registration marks. Carve or drill two small crosses outside the relief in the same CNC job. The laser software's print-and-cut feature jogs to each cross, and the burn follows. This is the most precise method of all, because no camera or photo is involved.
- A jig. Cut a pocket from scrap once, and never move it. Every carving drops into the same spot at the same angle, so repeat orders need no alignment at all.
Whichever you use, frame the job before you burn: most laser software can trace the outline with the laser off or at very low power, which shows you exactly where it is about to go.
If you own a WeCreat laser
WeCreat lasers can be run from WeCreat's own software, which uses the machine's camera, or from LightBurn over a USB cable. WeCreat publishes the LightBurn setup on its own support pages: it needs a LightBurn licence that supports G-code machines, a recent version of LightBurn, and WeCreat's configuration file. Owners running it that way report that the WeCreat camera and the autofocus are not available inside LightBurn.
That makes a WeCreat a good example of both routes. In WeCreat's own software you can use the camera and the ghost outline. In LightBurn you use the no-camera methods above, which are just as accurate, and for registration marks more so. We have not tested a WeCreat ourselves, so check WeCreat's current instructions before you start; they change as the software does.
What to burn onto a carving
Less is usually more. The carving is the subject; the burn should support it, not paint over it.
- Darken the background floor. The single biggest improvement. The relief stands out from a darker ground the way it does under raking light. Keep the burn a little away from the carved walls so it does not creep up the sides.
- Scorch the raised tops. A light toast on the highest surfaces gives an aged, two-tone look, lovely on rustic and reclaimed pieces.
- Outline the relief. A thin burned line around the carving's silhouette sharpens it, especially on busy grain.
- Burn the design's own shading. Tone that follows the height of the relief, darker where it is deep. Subtle on a deep carving, powerful on a shallow one.
- Add text. A name, a date, a message, placed on the carving itself rather than squeezed below it.
Focus, power and the first test
A relief is not flat, and a laser is focused at one height. Focus on the surface you are burning: the floor for background shading, the tops for scorching, the text area for text. On a deep carving the floor and the tops can be 20 mm apart, which is far outside most lasers' sharp focus range, so do the two as separate jobs if you want both.
Power and speed depend on your machine, your lens, your air assist and your wood, even on two boards from the same tree. Nobody can give you settings that are right for your laser; anyone who does is guessing. Burn a small test grid on an offcut of the same board once, pick the square you like, and use those numbers. It takes ten minutes and saves the carving.
CNC Match in Laser Studio
Everything above can be done by hand. We built it into our own laser app because we kept doing it by hand. Laser Studio is a desktop app for Windows, and its CNC Match tab does the whole job: load the design's PNG and a photo of the carved piece on your laser, and it lines them up for you.
- Auto-fit finds the piece in the photo and places the design on it. It runs on your own computer, offline, and tells you how sure it is; when it is not, you take over by hand.
- Hand grips on the frame move, resize, rotate and stretch the width or height on its own, with a see-through overlay and an opacity slider.
- Straighten the photo against the board or the bed, so the design lands at its real size and you get the exact position in millimetres or inches.
- A live burn preview on your own piece: darkened floor, scorched tops, outline, shading and text.
- One export with the burn files, the ghost outline, registration marks, a jig, a proof picture of the burn on your photo, and a read-me written for your laser software, including LightBurn without a camera.
It does not control your laser. It makes the files, and you burn them in the software you already use.
The design in the photographs at the top of this guide is our howling wolf and crescent moon, which carves beautifully and takes a darkened floor well:
Download the howling wolf and crescent moon · $7.99
Questions people ask
Do I need a laser with a camera?
No. A camera is convenient for quick one-offs, but typed position numbers, registration marks and a jig are all at least as accurate, and registration marks are the most accurate method of all.
How accurate is it?
From a straightened photo, typically within about a millimetre. Registration marks do better. Always check the outline against the carving and burn an offcut first.
Can I burn onto a carving I made from someone else's file?
Yes, as long as you have an image of the design at the same size and outline as the carving. It works best with files that ship with a matching PNG, as all of ours do.
My carving came out slightly squashed. Can the burn follow it?
Yes. Stretch the width or the height of the design on its own until it matches the carving. That feature exists because a customer asked for exactly this.
Does it work with my laser?
The files are ordinary PNG and SVG, so they work with any laser software that can import an image. The method is the same everywhere; only the menu names differ.