Convert 3DS to OBJ Online
Upload a .3ds file and download a Wavefront .obj containing the geometry of every object merged into one mesh. Two things to expect: no materials come across, and the model arrives rotated 90 degrees, so plan on standing it upright after import.
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What a 3DS file holds, and what the OBJ gives you
.3ds is the chunk-based file written by Autodesk 3D Studio and still produced by 3ds Max exports. It comes from the DOS era: object names are short, and vertex counts live in 16-bit fields, which caps each object at 65,535 vertices. Many older model libraries still ship .3ds, but 3DS import is now missing, optional or unreliable in a lot of current tools and in practically every web viewer, so the file often will not open where you need it.
On our servers the upload goes to a Python reader written for this format. It walks the chunk tree and takes only the parts it needs: the main chunk, the 3D editor chunk, the object and mesh blocks, the vertex array and the face array. Those meshes become a single trimesh object with every object in the scene merged together, facet winding is made consistent, and the result is written as .obj. No Autodesk software or plugin is involved.
What you get back is geometry and nothing more. Material definitions, texture file names, UV coordinates, smoothing groups, object hierarchy and pivots, cameras, lights and keyframes all sit in chunks the reader skips, so the download is a lone .obj with no .mtl beside it. The coordinates are also written through without an axis change, and because OBJ is a Y-up format while the data is Z-up, the mesh imports rotated 90 degrees about X, as if lying on its back. Rotate it back in your importer or in the 3D app before you start work.
This is the route to take when a legacy asset has to enter a current pipeline: an old architectural prop headed for Blender or Maya, a library download you intend to re-texture, or geometry for ArchiCAD, Unity or a web viewer that reads OBJ but not 3DS. If the asset still exists as a .max scene, exporting OBJ or FBX straight out of 3ds Max will keep far more than this path can.
How to convert 3DS to OBJ
- Check that the file really is a 3D Studio mesh. The reader verifies the leading chunk ID 0x4D4D and stops with a "Not a valid 3DS file" message on anything else, including renamed .max scenes.
- Drop the .3ds onto this page or pick it with the file button. Up to 10 files can go in one batch, and each one is converted on its own.
- Leave textures out of it. Material and bitmap chunks are never read, and this page accepts a single .3ds file, not an archive of model plus images.
- Start the conversion and wait. A model of a few megabytes is usually done in a few seconds; dense meshes take longer.
- Download the .obj, import it, then rotate the object 90 degrees about the X axis to stand it upright. If it lands upside down, rotate the other way.
- Assign materials in your 3D app, and set the scale there as well, since the numbers from the 3DS file are copied over as they are and OBJ carries no unit.
What this converter actually does
- A dedicated 3DS chunk parser, so files that modern 3D applications refuse to import still convert here.
- Every object in the scene arrives as one mesh with consistent facet winding.
- A single plain .obj to download, with no .bin, no texture folder and nothing to keep in sync.
- Clear failure text rather than a blank error: a file that is not a 3D Studio mesh is named as such by its magic number, and a file whose mesh chunks are missing or whose face list is damaged reports the engine's own reason.
- Up to 50 MB per file without an account, 100 MB with a free account, 200 MB on Plus and 1 GB on Pro.
- Everything runs on our machines, so a tablet or a locked-down work laptop handles the job as well as a workstation.
Video Tutorial
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3DS to OBJ questions
Why is my model lying on its back after import?
The 3DS data is Z-up and OBJ is a Y-up format, and our pipeline writes the coordinates through unchanged, so the mesh ends up rotated 90 degrees about X. Select the object and rotate it 90 degrees about X (or -90 if it comes out upside down), then apply the rotation.
Where did the materials and textures go?
The parser reads only the vertex and face chunks, so material names, bitmap paths and UV coordinates are not carried into the OBJ and no .mtl file is written. Keep the original .3ds if you need to look up those material names in another program, and assign shaders in your 3D app.
Can I upload a .max file instead?
No. .max and .prj scene files are not accepted. In 3ds Max, export the scene as .3ds for this page, or better, export OBJ or FBX directly; if you already have FBX, our FBX to OBJ page keeps materials and UVs that the 3DS route cannot.
I get "Not a valid 3DS file (magic: 0x...)". What now?
The first two bytes are not the 0x4D4D chunk ID, so the file is not a 3D Studio mesh: usually a renamed file, a partial download, or a Nintendo 3DS game dump, which is an unrelated format with the same extension. Re-export the model from the program that made it.
Does the OBJ keep the real-world size of the model?
No step in this conversion changes units. The coordinate numbers are copied over, and OBJ declares no unit at all, so whichever unit the 3DS was authored in, the receiving app will interpret the numbers by its own rule. Measure one known dimension after import and scale once.
Can I convert several 3DS files in one go?
Yes, within the batch limit: 10 files per request for guests and free accounts, 25 on Plus, 50 on Pro. Each file produces its own .obj and is downloaded separately; there is no combined archive download. Guest and free traffic is also capped at 10 conversion jobs per hour per IP address.
Will quads and smooth shading come back?
No. 3DS stores triangles, and the smoothing group data is not read, so the OBJ is a triangle mesh with no shading hints. Use shade smooth, auto-smooth by angle, or a remesh step in your 3D application if you want smooth surfaces.
What happens to my file after the conversion?
The uploaded .3ds is deleted as soon as the job finishes, whether it succeeded or failed. The .obj stays available through its download link for about four hours and is then deleted automatically. The link is a long random token, not tied to your account and not single-use, so treat it as private; file names, sizes and outcomes are logged for operations.