Free OBJ test files and sample generator
Plain-text 3D geometry (vertices and faces). Widely supported for testing 3D viewers, converters and asset pipelines.
What is a .obj file?
OBJ: Wavefront 3D Model. Wavefront OBJ is the most widely supported 3D geometry format, plain text listing vertices and the faces that connect them. Almost every 3D tool imports it, which makes it the interchange baseline.
Why generate a test OBJ file?
- Test a 3D asset import or conversion pipeline.
- Verify vertex and face parsing, including index conventions.
- Check performance on a mesh with many polygons.
What you can put inside a .obj file
You get 2 content options for OBJ, so the file holds something meaningful rather than random padding: Solid mesh, Point cloud. For OBJ these are alternatives, so choose the one that matches what you need to test.
How a .obj file is identified
A .obj file has no signature at the start. A text format has no identifying leading bytes, so the extension and the reported media type are the only claims about it until a parser actually reads it, which is why validating uploads by extension alone is unsafe.
How the size lands on the exact byte
The format allows comments, so the padding is comment lines, legal, inert, and visible if you open the file.
Negative testing with broken OBJ files
- Invalid. Identifiable, but wrong inside, so it fails during parsing.
- Corrupted. The leading bytes are destroyed. Same length as the valid file.
- Incomplete. Truncated part-way, so it is genuinely shorter.
- Empty. Chosen under Content rather than File Condition: valid structure, no data.
Which failure to reach for, and what to assert for each, is covered in how to make a corrupted file for testing. For upload limits and type checks see testing file upload validation, and for this format's encodings, UTF-16 and BOM test files.
Sample OBJ content
v 0.0 0.0 0.0 v 1.0 0.0 0.0 v 0.0 1.0 0.0 f -3 -2 -1
This shows the shape of the file. Your download is generated fresh at the size you choose, so the values will differ.
How to open and verify the file
Open in Blender, MeshLab, Windows 3D Viewer or an online OBJ viewer.
Media type model/obj · extension .obj · category 3D
Generate a .obj file → · questions about sizes, privacy or cost are answered on the site FAQ.
Frequently asked questions about OBJ files
What identifies a .obj file?
Nothing at the start of the file does. A text format has no identifying leading bytes, so the extension and the reported media type are the only claims about it until a parser actually reads it, which is why validating uploads by extension alone is unsafe.
How can a .obj file be an exact number of bytes?
The format allows comments, so the padding is comment lines, legal, inert, and visible if you open the file.
What can go inside the OBJ file?
There are 2 content options for .obj: Solid mesh, Point cloud. For OBJ these are alternatives, so pick the one matching what you need to test.
Can I download several broken OBJ files at once?
Yes, select more than one File Condition and you get one ZIP containing a .obj per condition, each named after its condition.
Can the OBJ file use UTF-16 or a byte-order mark?
Yes. .obj is a text format, so it can be generated as UTF-8, UTF-8 with a byte-order mark, UTF-16 LE or UTF-16 BE. The body is shortened before re-encoding so the finished file still lands on the exact size you asked for. Note that a UTF-16 file always has an even byte count.
How do I open or verify the OBJ file?
Open in Blender, MeshLab, Windows 3D Viewer or an online OBJ viewer.