Use the biggest file you have
Edges are only as sharp as the pixels behind them. A 200 px icon stretched to 100 mm wide has steps half a millimetre across, and they show. We use up to 2048 px on the long side.
PNG to STL, as a relief or a real part
Attach your PNG and say what it should become. A relief takes its height from the picture. A keychain or a sign gets the ring holes and backing plate a picture can't show.
3 free generations, no credit card. Downloads need a pack from US$12 or a plan.
How to turn a PNG into an STL here
- 1
Drop in your PNG
A logo, an icon, a drawing or a screenshot. It stays in your browser until you sign up and send.
- 2
Say what it should become
A few words are enough, like "make a raised relief of this logo". Say which parts stand up if it matters.
- 3
Check it in 3D, then download
Turn the model around, ask for changes in plain words and download the STL or 3MF when it's right.
Two ways to get depth out of a PNG
A PNG is a grid of coloured pixels, with no depth and no edges. The usual PNG to STL converter makes a height map: each pixel becomes a little column, as tall as that pixel is dark or light. That suits a relief or a lithophane, and it's what you get here when you ask for one.
It's no good for a keychain. A ring hole isn't in the picture, a stamp has to be mirrored and a sign needs a backing plate. For those, the designer reads your PNG as a reference and builds the part from it, so the edges come close to your picture without being a pixel-perfect trace.
What to say in your message
Saying what it is will do: a relief, a keychain, a plaque. Add any of these if they matter to you.
- Which parts stand up: the dark ones or the light ones
- How big it ends up: "80 mm wide" settles it, since a PNG has no real size
- How thick the base plate is, and how tall the raised parts get
- What the picture leaves out: ring holes, screw holes, a stand
Getting a PNG ready for 3D printing
A clean picture makes a clean model. These four things make the biggest difference.
Mind the transparent parts
Transparent pixels count as white in a relief. A white logo on a transparent background comes out as a blank plate, so put it on a black background first and ask for the light parts to stand up.
Go black and white for logos
In a relief, grey means a slope. The soft grey edge around a logo becomes a ramp and a drop shadow becomes a bump. Two flat tones give you flat tops and steep sides.
Have the SVG? Use it
A vector file has real outlines, so nothing gets guessed. If your logo started in Illustrator, Inkscape or Figma, export an SVG and use our SVG to STL page.
How to convert PNG to STL for free, by hand
If a height map or a traced outline is all you need, you don't need us. All three of these are free.
PNG to STL in OpenSCAD
Scripted, and its surface() function reads a PNG as a height map directly.
linear_extrude(height = 1)
square([40, 20], center = true);
translate([0, 0, 4])
scale([0.2, 0.2, 0.03])
surface(file = "logo.png", center = true, invert = true);- Save the lines above next to logo.png and set the plate to your picture's size: pixels x 0.2 mm.
- Press F6 to render, and give it a minute.
- Press F7 to export the STL.
PNG to STL in Blender
Free and much more capable, with a real learning curve.
- Add a Grid mesh with about 500 x 500 subdivisions and scale it to real size.
- Add a Displace modifier, give it a new Image texture with your PNG and set Coordinates to UV.
- Set the Strength for your height, then add a Solidify modifier to close the shape.
- Use Object > Apply > Visual Geometry to Mesh, then File > Export > STL.
PNG to STL with Inkscape and Tinkercad
The way to clean outlines, if your logo has flat colours.
- Open the PNG in Inkscape and use Path > Trace Bitmap.
- Delete the original picture and save the result as an SVG.
- Import the SVG into Tinkercad and set its size and height.
- Click Export and choose .STL.
Height map converter, CAD app or GrandpaCAD?
They do different jobs. Pick by what your PNG has to turn into.
 GrandpaCAD | Height map converters | Tinkercad, Blender | |
|---|---|---|---|
| What you get | The part you described | A relief of the picture | Whatever you build by hand |
| Holes, handles, backing plates | Say so in the message | No | Model them yourself |
| Change it later | One sentence | Convert again | Back into the editor |
| Skill needed | None | None | Some to a lot |
| Price | 3 free generations, downloads from US$12 | Free | Free |
2,000+ people making real prints
Unedited feedback from the in-app rating prompt. We only show country to keep makers anonymous.
"generated a printable design on the first try!"
"Fast easy and good quality"
"It's working good. Grandpa!"
"yay so fun"
Pulled from real CSAT survey responses inside the GrandpaCAD app.
PNG to STL questions
Is this a free PNG to STL converter?
Partly, and I'd rather say so up front. Your first 3 generations are free with no credit card, so you can see your PNG built and turn it around in the 3D viewer. Downloading the STL needs a pack from US$12 or a plan. If a plain height map is all you want, OpenSCAD does that for free, and the steps are on this page.
Will the model match my PNG exactly?
It depends on what you ask for. A relief or a lithophane follows the pixels directly. A keychain, a sign or anything with added features is built by the designer using the PNG as a reference, so the outlines come close without being an exact trace. If you need exact outlines, start from an SVG.
What happens to a transparent background?
It counts as white. With a dark logo on a transparent background that's what you want, because the logo stands up from the base plate. A white logo on transparent has nothing to stand out from, so put it on black first.
Which parts stand up, the dark or the light?
Whichever you say. A black logo on white usually wants the dark parts raised. A lithophane always has the dark parts thickest, because they have to block the light.
What size will it print at?
Whatever you ask for. A PNG has pixels and no real size, so say "80 mm wide" and the height follows the picture's proportions. If you don't say, the designer picks a sensible size or asks you.
Why are height map STLs so big?
Because every pixel needs its own triangles. A 200 x 100 px picture comes to about 80,000 triangles in OpenSCAD's surface(). If a file from a free converter chokes your slicer, shrink it with our free Reduce STL File Size tool.
Can I download a 3MF instead of an STL?
Yes. You can download STL, 3MF, OBJ, GLB and GLTF. For a one-colour print either works, and a 3MF is smaller and keeps real millimetres.
Do I need CAD software or any 3D modeling experience?
No. It runs in the browser and you never touch a CAD program. The STL opens in Bambu Studio, PrusaSlicer, Orca and any other slicer.
Related guides and tools
- JPG to STLGot a photo instead? Lithophanes, lamp shades and figurines from a JPG.
- SVG to STLGot the vector file? Exact outlines, with nothing guessed.
- Image to 3D modelTurn a sketch or a photo of a part into an editable 3D model.
- Reduce STL file sizeHeight map too heavy for your slicer? Shrink it in your browser, free.
- Repair an STLFix holes and bad normals in an STL from another converter, free.
- Scale an STLCame out the wrong size? Rescale it in the browser, free.
Got the PNG?
Say what it's for.
3 free generations, no credit card. See your part in 3D before you pay anything.