Convert OBJ to AMF
Free OBJ to AMF converter that runs in your browser. See real dimensions before you download.
How to convert OBJ to AMF
- Drop your OBJ file (with its textures, if separate) onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose AMF as the output and click Convert. Several files download as one ZIP.
What carries over from OBJ to AMF
| OBJ | AMF | Result | |
|---|---|---|---|
| Colour / materials | Yes | Yes | Kept |
| Textures | Yes | No | Dropped |
| Units stored in file | No | Yes | Written as mm |
| Separate parts | Yes | Yes | Kept |
| Usual up axis | Y | Z | Rotated (switchable) |
About OBJ files
OBJ comes from Wavefront Technologies' Advanced Visualizer software in the 1980s, and it has outlived the product. A file is plain text: lines starting with v define vertices, vt texture coordinates, vn normals, and f faces that reference those lists by index. Faces may be triangles, quads or larger polygons, and the g and o keywords group faces into named objects. Appearance is not in the OBJ at all; a line called mtllib points to a separate .mtl file that lists materials with diffuse colours and texture image names. The format is verbose, has no official unit and no scene hierarchy or animation, but it is trivial to read and write. That is why scanners, photogrammetry tools, sculpting programs and game pipelines still use it to move static meshes around.
About AMF files
AMF was standardised as ASTM F2915 and later ISO/ASTM 52915, with the aim of fixing the shortcomings of STL for additive manufacturing. A file is XML, optionally compressed as a ZIP, and describes one or more objects made of a vertex list and volumes of triangles. Unlike STL, it declares units, such as millimetre, inch or micrometre, and can attach colours and materials to volumes or even to individual triangles, with gradients between them. The specification also allows curved triangles, constellations that arrange several objects, and custom metadata. In practice it was overtaken by 3MF, which came from industry backers and gained support in Windows and the main slicers. AMF files still appear from some multi-material printers and research tools, and from older exporters in Cura, Slic3r and Meshmixer.
3D printing notes
Slicers import OBJ geometry and ignore the material file, so what you print is the shape only. Bambu Studio and OrcaSlicer can use the colours from an OBJ for multi-colour assignment on import, but results depend on the exporter. The main trap is orientation and scale. Blender usually writes Y-up files while slicers expect Z-up, so a model may arrive lying on its back, and a model sculpted at one unit per metre can be tiny. MeshShift has an Up-axis fix that rotates Y-up models so they stand upright, shows real dimensions before conversion, and can convert OBJ to STL or 3MF in the browser.
Frequently asked questions
Is this OBJ to AMF converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your OBJ file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.
Why does my OBJ import without its colours or textures?
The colour information is in a separate .mtl file and image files. If the MTL or textures are missing, renamed or in another folder, the importer shows plain grey geometry. Keep the OBJ, MTL and images together, or convert to GLB, which packs them in one file.
Is AMF better than STL?
On paper, yes: it has units, colour, materials and several objects. In practice STL is accepted everywhere and AMF is not, and 3MF now fills the same role with much wider support. Use AMF only when a specific tool or workflow requires it.