# OBJ File Viewer

> Open Wavefront OBJ files from Blender, ZBrush, scanners or AI generators with their colors and textures. Drop the .obj with its .mtl and images, or the whole folder as a .zip.

Page: https://printpal.io/tools/obj-viewer
Updated: 2026-11-12
Use it: open https://printpal.io/tools/obj-viewer in a browser and drop a file. Free, no account, files are processed locally and never uploaded.

An OBJ is plain text: vertices, faces, UVs and normals, with materials in a separate **.mtl** file that points at texture images. That split is why OBJs so often open grey: the viewer only got the .obj. Drop the .obj, .mtl and images together, or a .zip of the folder, and the viewer matches every reference by file name, even when the .mtl was written with absolute Windows paths.

OBJ has no units and no fixed up axis. The viewer assumes Y up, the convention of Blender and most 3D apps, and reads the numbers as millimetres. If the size looks wrong (a figure 1.8 mm tall was made in metres) it suggests a fix; switch to Z up if the OBJ came from CAD or a slicer.

## How to use the OBJ viewer

1. **Open the file.** Drop the .obj with its .mtl and texture images, or a .zip of the folder.
2. **Check size and orientation.** The model stands on the plate in millimetres. Switch to inches, or change the file units or up axis if it looks wrong.
3. **Run the checks.** Read the mesh check, pick your printer to see whether it fits, and use Measure (M) or Section (X) for a closer look.
4. **Save or convert.** Take a PNG screenshot, or save the model as STL, 3MF, OBJ, GLB, PLY or USDZ.

## What you can check

- Materials and textures from the .mtl, or vertex colors written in the OBJ
- Size in mm or inches, with a one-click fix for files made in metres
- Triangle count, separate objects and a watertight check for printing
- Wireframe and smooth shading to inspect topology
- Save as STL, 3MF, GLB or USDZ

## OBJ at a glance (Wavefront OBJ)

OBJ came out of Wavefront Technologies' animation software and became the plain-text lingua franca of 3D. The geometry is in the .obj; colors and texture references live in a companion .mtl file, which is why OBJs so often arrive grey.

- **Stores:** Vertices, faces (triangles, quads, n-gons), UVs and normals as text
- **Color:** Materials and textures in a separate .mtl file; vertex colors as an unofficial extension
- **Units:** None, the numbers are bare
- **Up axis:** Y by convention (Blender, Maya, most 3D apps)
- **File size:** Text: about a binary STL's size for bare geometry, up to twice that with UVs and normals
- **Opens in:** Blender, Maya, 3ds Max, ZBrush, Cinema 4D, game engines, most slicers

## Tips

- **Grey model?** The .mtl or textures are missing. The note under Model lists the files the OBJ asked for, so you know what to add.
- **Lying on its back?** Switch the up axis to Z. OBJs exported from CAD and slicers are usually Z up.
- **Printing in color?** Convert to [3MF](https://printpal.io/convert/obj-to-3mf) to turn material colors into filaments, or use the [AMS converter](https://printpal.io/tools/ams-converter) for textured models.

## FAQ

### Why does my OBJ show without textures?

OBJ keeps colors in a separate .mtl file and textures in image files. Drop all of them together, or zip the folder. The viewer matches files by name, so absolute paths in the .mtl are fine.

### Can I open an OBJ file on my phone?

Yes. The viewer works in Safari and Chrome on iOS and Android. Zip the folder first to bring the .mtl and textures along.

### What is the difference between OBJ and STL?

Both store surfaces. OBJ shares vertices and can keep UVs, normals, quads and materials; STL stores only loose triangles. Slicers read both, but STL is the safer choice for print services and OBJ for 3D apps.

### Is the viewer free? Are there limits?

Free, with no sign-up, watermark or file limit. The practical limit is your device's memory: files of a few hundred MB open on most laptops.

### Are my files uploaded anywhere?

No. Files are read by JavaScript and WebAssembly in your browser and never sent to PrintPal. Only the code is downloaded, and the STEP and IGES reader once, from a public CDN.

## Related

- [OBJ to STL Converter](https://printpal.io/convert/obj-to-stl)
- [OBJ to GLB Converter](https://printpal.io/convert/obj-to-glb)
- [OBJ to 3MF Converter](https://printpal.io/convert/obj-to-3mf)
- [OBJ to USDZ Converter](https://printpal.io/convert/obj-to-usdz)
- [STL to OBJ Converter](https://printpal.io/convert/stl-to-obj)
- [STEP to OBJ Converter](https://printpal.io/convert/step-to-obj)
- [GLB to OBJ Converter](https://printpal.io/convert/glb-to-obj)
- [FBX to OBJ Converter](https://printpal.io/convert/fbx-to-obj)
- [3D model viewer](https://printpal.io/tools/3d-model-viewer)
- [3D model converter](https://printpal.io/tools/3d-model-converter)
- [Mesh Repair](https://printpal.io/tools/mesh-repair)
- PrintPal for LLMs: https://printpal.io/llms.txt