PNG → Printable STL: contours for stamps, or heightmaps for reliefs & lithophanes. Free online.
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Designed for PNG images, the tool uses transparent channels to extract precise contours, making it ideal for stamps and logos. For regular photos, the heightmap mode converts them into reliefs or lithophanes. You can adjust the resolution before exporting the STL file, and all processing is done locally in your browser.
Use Outline Extrude: only the visible shape becomes solid.
Transparent pixels are left empty, so the outline is cut cleanly with no background to remove.
Choose Extrude Height. If the logo has separate pieces, set Base to Follow Outline or Rectangle so they stay joined.
Download the STL and scale it to its final size in your slicer.
Use Heightmap: brightness becomes height.
Use Raise By to decide which parts stand up: dark areas for a lithophane, light areas for a raised picture.
Set Relief Height and Minimum Base Thickness. Add a little Smoothing if the photo is noisy.
Download the STL. For a lithophane, print it upright in a light colour and hold it up to a light.
A keychain or stamp from a logo
Try: Outline Extrude, Base: Follow Outline, and a few millimetres of Extrude Height.
A backlit photo lithophane
Try: Heightmap, Raise By: Dark Raised, and a thin Minimum Base Thickness.
A smoother surface from a noisy photo
Try: Raise Smoothing a little and lower Detail.
Fewer stray shapes around a logo
Try: Raise Ignore Small Specks and adjust Threshold.
Outline Extrude100mm10mm – 500mmonBy BrightnessBy Brightness · Remove by Color · Keep Background
#ffffff150 – 100WhiteWhite · Black
1280 – 255101 – 100 · step 0.10.50 – 5 · step 0.131 – 8375 – 9010.1 – 2 · step 0.1NoneNone · Rectangle · Follow Outline · Circle
2mm0.5mm – 10mm · step 0.1mm3mm0mm – 20mm · step 0.1mm6416 – 256#e1e1e1Dark PartsDark Parts · Light Parts
121 – 16150 – 20000 – 4 · step 0.0550.5 – 20 · step 0.110 – 5 · step 0.120 – 10400100 – 400 · step 50onDark RaisedDark Raised · Light Raised · Vivid Raised · Custom per Color
0.50 – 3 · step 0.100 – 3 · step 0.131 – 10stl|Open With: Slicer Software、MeshLab、Windows 3D Viewer、STL Viewer Online
PNG files with a transparent background give the cleanest outlines, because empty areas are dropped instead of printed. Then match the printer settings to what you are making.
| What you are making | Slicer settings | Reason |
|---|---|---|
| A cookie cutter or stencil | Flat, 0.2 mm layers, 2 walls, no infill needed. | Thin walls cut cleanly and print in minutes. |
| A two-colour logo | Pause at the layer where the raised part starts and swap filament. | Gives a second colour without a multi-colour printer. |
| A lithophane | Upright, 100% infill, 0.12 mm layers, white PLA. | Even thickness gives even light. |
| A wall sign | Flat, 0.2 mm layers, 15% infill, brim on. | A brim stops corners lifting on large flat parts. |
In Outline Extrude mode, transparent areas typically generate no geometry (hollow), leaving only the opaque subject, ideal for stamps and silhouettes. In heightmap mode, brightness determines thickness; transparency is processed as previewed.
No. STL only stores geometry. For colored models, use the 'PNG to 3MF' converter, or paint after printing.
Outline Extrude mode extracts regions by brightness, so a busy or colored background, or anti-aliased edges, can produce stray shapes. Crop the subject, use a clean transparent background, and adjust the threshold to ignore faint areas.
The exported file is written in millimeters. The vertical settings (depth, max height, base thickness) are mm, but the horizontal footprint follows the image's pixel grid, so check the size in your slicer and scale the model to the dimensions you need.