# PNG to STL Converter

> To convert a PNG to STL, turn its opaque pixels into a solid shape of a chosen height and leave the transparent pixels out. Kenerate's free tool does this in your browser, so a logo with a transparent background becomes a printable cut-out. Opaque PNGs use a brightness threshold instead. Download STL or 3MF in millimetres.

URL: https://kenerateai.com/png-to-stl
Publisher: Kenerate AI (https://kenerateai.com)
Last updated: 2026-10-01

## Key facts
- Price: Free, no account
- Solid parts: Opaque (≥50% alpha) pixels; on opaque PNGs, pixels darker than the threshold
- Default: 80 mm wide · 4 mm shape · no plate
- Modes: Extrude shape · Relief · Lithophane
- Output: STL, 3MF, OBJ, GLB in millimetres
- Privacy: Processed in your browser — no upload
- Transparency is the cut line: A logo exported with a transparent background already says what's object and what's not. The tool uses that edge directly.
- Sharp, lossless edges: No JPEG blocks or halos, so outlines and small text come out cleaner.
- Plate or no plate: Print just the shape, or put it on a backing plate for a sign or badge.
- Threshold control: For black-on-white PNGs without transparency, move the threshold until the shape is clean.
- Read alpha: The PNG's transparency and brightness are sampled on a grid every 0.1–1 mm.
- Decide solid: Opaque pixels (or pixels darker than the threshold) are marked solid.
- Build: Solid cells become a block of your chosen height, with walls along every outline.
- Export: The watertight mesh is written as STL, 3MF, OBJ or GLB.
- STL (Stereolithography): Triangle mesh (binary or ASCII); by 3D Systems, 1987. Holds: Triangle surfaces, Facet normals. Lacks: Colour and textures, Units, Materials. Best for: 3D printing — every slicer opens it. Opens in: Cura, PrusaSlicer, Bambu Studio, OrcaSlicer, Blender.
- 3MF (3D Manufacturing Format): ZIP package with XML; by 3MF Consortium, 2015. Holds: Meshes with units (millimetres), Colours and materials, Several objects and build plates. Lacks: Animation. Best for: Modern 3D printing and multi-colour prints. Opens in: Bambu Studio, PrusaSlicer, OrcaSlicer, Cura, Windows 3D Builder.

## Steps
1. Add the PNG — Drop your .png onto the box above, or try the sample logo.
2. Check the outline — For opaque PNGs, adjust the threshold until the shape is clean.
3. Set height and size — Choose the width, shape height and an optional base plate.
4. Download — Download the STL or 3MF and slice it.

## In depth

### Alpha is the cleanest outline you can get
A transparent PNG stores an alpha value per pixel, so the edge between logo and background is explicit. That's better than guessing it from colour, which fails on white parts of a logo against a white background.

### Grid size and smoothness
The outline steps at the grid size you choose — 0.25 mm by default, finer than most FDM nozzles can draw. Below about 0.45 mm wide, features can't print at all with a 0.4 mm nozzle; 0.9 mm is a safer minimum [11].

### When to use SVG instead
Vector files describe curves exactly, so they extrude without steps at any size. If you have an SVG of your logo, the SVG to STL tool gives smoother edges and can raise each colour to its own height.

References:
[1] Wikipedia — STL (file format): https://en.wikipedia.org/wiki/STL_(file_format)
[2] Wikipedia — Wavefront .obj file: https://en.wikipedia.org/wiki/Wavefront_.obj_file
[3] Wikipedia — FBX: https://en.wikipedia.org/wiki/FBX
[4] Khronos Group — glTF: https://www.khronos.org/gltf/
[5] 3MF Consortium — 3MF specification: https://3mf.io/specification/
[6] Wikipedia — Universal Scene Description (USD / USDZ): https://en.wikipedia.org/wiki/Universal_Scene_Description
[7] Wikipedia — PLY (file format): https://en.wikipedia.org/wiki/PLY_(file_format)
[8] Khronos Group — glTF 2.0 specification: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html
[9] Apple — AR Quick Look: https://developer.apple.com/augmented-reality/quick-look/
[10] three.js — documentation: https://threejs.org/docs/
[11] Prusa Knowledge Base — Modeling with 3D printing in mind: https://help.prusa3d.com/article/modeling-with-3d-printing-in-mind_164135
[12] Prusa Blog — lithophanes and filament transparency: https://blog.prusa3d.com/lets-play-with-filament-transparency-how-to-make-amazing-lifelike-color-photos-with-just-a-simple-color-change_104338/
[13] Polymers (2024) 16(20):2862 — FFF parameters and translucency of PLA: https://doi.org/10.3390/polym16202862
[14] Wikipedia — Lithophane: https://en.wikipedia.org/wiki/Lithophane
[15] W3C — CSS Values and Units Level 3 (absolute lengths): https://www.w3.org/TR/css-values-3/
[16] Adobe Substance 3D — OpenGL vs DirectX normal maps: https://experienceleague.adobe.com/en/docs/substance-3d/bakers/common-questions/what-is-the-difference-between-the-opengl-and-directx-normal-format
[17] Blender Manual — Normal Map node: https://docs.blender.org/manual/en/latest/render/shader_nodes/displacement/normal_map.html
[18] Wikipedia — Normal mapping: https://en.wikipedia.org/wiki/Normal_mapping
[19] SIL Open Font License: https://openfontlicense.org/

## FAQ
Q: Can you convert PNG to STL?
A: Yes. A PNG is flat, so the converter turns either its opaque area (transparent PNGs) or its dark area (opaque PNGs) into a solid shape, or turns brightness into height for photos.

Q: What happens to transparent pixels?
A: They're left out. Pixels at 50% opacity or more become solid; the rest are empty space.

Q: My logo has a white background — will that work?
A: Yes. Without transparency, the threshold decides: pixels darker than it become solid. Tick Invert for a light logo on a dark background.

Q: Why are the edges stepped?
A: The outline follows a grid. Use a smaller grid step for smoother edges, or start from an SVG for perfectly smooth curves.

Q: Should I convert PNG to SVG first?
A: For logos you'll print large or often, yes — an SVG gives smooth curves. For quick prints, extruding the PNG directly is fine.

Q: Can I keep the colours?
A: Not in STL. To print colours, use a multi-material printer and split the design into layers — the SVG tool can raise each colour to its own height.

Q: Is my PNG uploaded?
A: No. It's processed in your browser.

## Related pages
- AI 3D Model Generator: https://kenerateai.com/ai-3d-model-generator
- Image to 3D: https://kenerateai.com/image-to-3d-converter
- AI STL Generator: https://kenerateai.com/ai-3d-printing-model-generator
- Text to 3D: https://kenerateai.com/text-to-3d-generator

## Sources
- Wikipedia — STL (file format): https://en.wikipedia.org/wiki/STL_(file_format)
- Wikipedia — Wavefront .obj file: https://en.wikipedia.org/wiki/Wavefront_.obj_file
- Wikipedia — FBX: https://en.wikipedia.org/wiki/FBX
- Khronos Group — glTF: https://www.khronos.org/gltf/
- 3MF Consortium — 3MF specification: https://3mf.io/specification/
- Wikipedia — Universal Scene Description (USD / USDZ): https://en.wikipedia.org/wiki/Universal_Scene_Description
- Wikipedia — PLY (file format): https://en.wikipedia.org/wiki/PLY_(file_format)
- Khronos Group — glTF 2.0 specification: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html
- Apple — AR Quick Look: https://developer.apple.com/augmented-reality/quick-look/
- three.js — documentation: https://threejs.org/docs/
- Prusa Knowledge Base — Modeling with 3D printing in mind: https://help.prusa3d.com/article/modeling-with-3d-printing-in-mind_164135
- Prusa Blog — lithophanes and filament transparency: https://blog.prusa3d.com/lets-play-with-filament-transparency-how-to-make-amazing-lifelike-color-photos-with-just-a-simple-color-change_104338/
- Polymers (2024) 16(20):2862 — FFF parameters and translucency of PLA: https://doi.org/10.3390/polym16202862
- Wikipedia — Lithophane: https://en.wikipedia.org/wiki/Lithophane
- W3C — CSS Values and Units Level 3 (absolute lengths): https://www.w3.org/TR/css-values-3/
- Adobe Substance 3D — OpenGL vs DirectX normal maps: https://experienceleague.adobe.com/en/docs/substance-3d/bakers/common-questions/what-is-the-difference-between-the-opengl-and-directx-normal-format
- Blender Manual — Normal Map node: https://docs.blender.org/manual/en/latest/render/shader_nodes/displacement/normal_map.html
- Wikipedia — Normal mapping: https://en.wikipedia.org/wiki/Normal_mapping
- SIL Open Font License: https://openfontlicense.org/