How to open STL, OBJ, 3MF and PLY files on Android
Open 3D print files in STL Viewer from the file picker, Open with, the share menu or a ZIP, add OBJ colors from the MTL file and handle large models.
STL Viewer opens 3D print files straight from your phone or tablet, wherever they came from: a download, an email attachment, a chat, a cloud storage app or a USB stick. Everything is read on the device, so it works without internet and nothing is uploaded.
Open a model in four ways
- Open file. On the home screen, tap Open file and pick the model in the Android file picker. You can select several files at once, which matters for OBJ models (see below).
- Open with. In a file manager, email or chat app, tap the file and choose STL Viewer in the "Open with" list.
- Share. In apps that offer a share button instead, share the file to STL Viewer.
- Recent files. Every model you open is added to the home screen with a thumbnail, so you can reopen it with one tap.
Nothing to open yet? Tap Try a sample model and pick one of six originals: a gear, a vase, a bracket, a phone stand, a calibration cube or an owl in five colors.
Which files work
| Format | What STL Viewer reads |
|---|---|
| STL | Binary and ASCII |
| OBJ | The mesh, plus colors from its MTL file |
| 3MF | Units, colors and several objects |
| PLY | ASCII and binary, for example from a 3D scan |
| ZIP | The largest model inside the archive |
The app checks each file by its content, not only its name, so a model with a wrong or missing extension usually still opens.
OBJ with colors
An OBJ keeps its colors in a separate .mtl file. Select both files together in the picker. If you open only the OBJ, the model appears in your model color and a note tells you which MTL file is missing.
ZIP archives
Many model sites deliver a ZIP. STL Viewer opens the largest model inside it and shows a short note with its name. Other archive types (such as RAR or 7z) need to be extracted first.
Files it can't open
STEP, IGES, glTF/GLB, FBX, SCAD, DXF, DWG and similar formats aren't supported yet. Export the model as STL, OBJ or 3MF from the program it was made in, then open that file. A G-code file is a slicer's instructions for the printer, not the model itself: open the STL, OBJ or 3MF it was sliced from instead.
Large files
Big models load with a progress bar and a Cancel button. Models with millions of triangles show a simplified view on screen, but model info and export always use the full model. Files shared from other apps have a size limit; if you hit it, save the file on your device first and open it with Open file.
Without Premium, the home screen shows your 10 most recent files. Older ones are hidden, not deleted, and Premium shows them all.
Once the model is open, learn the gestures and view modes. For more ways to get a file onto your phone, read how to open STL files on Android.
Learn more on the blog
- How to Open STL Files on Android (Offline, No PC Needed)
- OBJ Viewer: Open OBJ Files with Colors (OBJ + MTL) on Android
- 3MF Viewer: What a 3MF File Is and How to Open It on Your Phone
Questions and answers
Why does my OBJ model have no colors?
The colors are stored in a separate .mtl file. Select the .obj and the .mtl together in the file picker and the colors appear.
Can STL Viewer open STEP or GLB files?
No. Export the model as STL, OBJ or 3MF in the program it was made in, then open that file in STL Viewer.
What happens when I open a ZIP file?
STL Viewer opens the largest STL, OBJ, 3MF or PLY model inside the ZIP and shows a note with its name.
More guides
Check your next print on your phone
Free STL, OBJ, 3MF and PLY viewer for Android. Works offline.