Add text to an STL – as a flush colour inlay
Most “emboss text on STL” tools stick letters on top of the surface. This one inlays them: the text is cut into the model to the depth you choose and the cut-out becomes its own part. Both parts fit exactly – together they are your original model again – so the surface stays level and the colour edge is sharp. That is what multi-colour printers do best.
How it works
- Open your model. STL, OBJ or 3MF, read with the same engine as our STL Repair tool. Files that aren’t watertight are sent to Repair first.
- Type and place. Click on the model – the text lands there and follows the surface: flat faces, cylinders (wrapped without stretching) and gentle domes. Drag it, or use the arrow keys and buttons to move, turn, resize and space it, in any of the 28 keychain fonts.
- Optionally paint an area with the brush, smart fill or eraser – the text is then fitted to that area.
- Download the colour 3MF (body on filament 1, text on filament 2), or the body and text inlay STLs.
Warnings you may see
- Crosses a sharp edge – the letters would bend round a corner; move them onto one face.
- Curves tightly – the radius is small for this text (under ~3× its height) or the depth is over a quarter of the radius.
- Small / thin letters – under 4 mm high, or strokes thinner than two nozzle lines (0.8 mm).
- Heavy model – over ~500,000 triangles everything is slower; simplify it in STL Repair.
Add a texture to an STL
Paint where the grip or pattern should go and pick one of six tileable textures – knurl, hex, wood grain, carbon weave, dots, stripes – or your own greyscale image. The preview is instant (no geometry yet); Generate then splits only the painted triangles finely enough for the pattern (detail, in mm), pushes each point along the surface normal by the texture height and fades it out over the edge blend, so there is no step at the border. Everything outside the paint is left exactly as it was. Big areas at fine detail make big files: the triangle count is shown before you generate, and anything over 2 million triangles is refused with a hint to use a coarser detail.
Single-colour printer?
On a flat face you can still get two colours: print with a pause / filament change at the layer where the text starts (lettered face up) or ends (lettered face on the bed). Pick a depth that is a whole number of layers.
Frequently asked questions
How do I add text to an STL file?
Open your STL (or OBJ / 3MF), type your text, then click on the model where it should go. Drag it, use the arrow keys or the buttons to move, turn, resize and space it. The text follows the surface – flat faces, cylinders and gentle domes – and is cut into the model as a flush inlay. Download the colour 3MF (or the two STLs) and print.
Is this embossed or engraved text?
Neither – it is an inlay. The letters are cut a fixed depth (0.6–1.2 mm, 0.8 mm by default) into the model along the surface, and the cut-out becomes a second part that fills it exactly. The outer surface stays perfectly level, so a lettered face can even lie on the print bed, and the colour boundary is crisp.
Which printers is it for?
Multi-colour printers: Bambu Lab AMS, Prusa MMU, Snapmaker U1, tool changers and other multi-material setups. The colour 3MF opens in Bambu Studio, OrcaSlicer and PrusaSlicer as one object with two parts already set to filaments 1 and 2.
Can I do it on a single-colour printer?
On a flat face that lies on the bed, or faces up at the top, yes: print with a pause / filament change at the layer where the text starts or ends (“Pause at layer” or M600 in your slicer). Set the depth to whole layers (e.g. 0.8 mm = 4 layers of 0.2 mm). On curved faces it only works with a multi-colour printer.
Why does it ask me to repair my file first?
Cutting an inlay needs a closed, watertight solid. If your file has holes, flipped or doubled faces, “Repair it first” opens it in our free STL Repair tool; after repairing, send it straight back here.
Can I limit the text to one area?
Yes – paint it. Brush, smart fill (spreads over a smooth area up to an angle you choose), eraser, grow and shrink mark triangles in an instant. Tick “Fit text to the painted area” and the surface under the text is fitted from the painted faces only, and you are warned if the text leaves them.
Can I add a logo too?
Yes. Click “+ Logo / image” and pick a built-in logo, an SVG (its filled shapes are used as they are, white shapes cut holes) or a PNG / JPG, which is traced to outlines – set the threshold, invert, smoothing and speck size and check the traced outline preview. A logo is placed, dragged, nudged, turned and sized exactly like text, and you can have up to four items (text and logos) on one model, each on filament 2 or 3.
Can I add a texture, like knurling, to an STL?
Yes. Paint the faces to texture, choose knurl, hex, wood grain, carbon weave, dots or stripes – or upload your own PNG / JPG / SVG as a heightmap – and set the pattern size, rotation and depth (0.2–1.5 mm). The pattern shows live on the painted area; Generate then subdivides only that area and pushes it out (raise) or in (sink, which keeps the outer size for parts that must fit), blending to nothing at the edge of the paint. Download it as a single-colour STL or 3MF.
Is it free? Is my file uploaded?
Free, no sign-up, no watermark. Your model is read and cut by your own browser – nothing is uploaded.