Convert 3DM to OBJ (Free)
Also converts STL, GLB, PLY, USDZ, 3MF, WRL from the same file.
Runs in your browser. No upload, no signup, nothing to install.
Also from Innerscene: Circadian Lab, a free lighting calculator for room illuminance, melanopic EML, and glare.
How to convert 3DM to OBJ
- 1
Open your .3dm file
Drag it onto the viewer above, or click "Open a 3DM File". Files up to 200 MB open directly; the parse runs in a worker so the page stays responsive.
- 2
Pick Wavefront OBJ in the Export menu
Click Export in the toolbar, then OBJ (.obj).
- 3
Download
The .obj is written in the browser and saved straight to your downloads folder. No queue, no email, no watermark.
What survives the conversion
A file conversion is a translation, and formats do not carry the same things. Here is exactly what moves from 3DM into OBJ, and what does not.
| Geometry | Reduced | 3DM stores exact B-rep solids and OBJ stores triangles, so the surfaces are tessellated. Curved faces become faceted at the display tolerance, which is fine for visualization, printing and clash checking, but not for further parametric CAD work. |
|---|---|---|
| Colors and materials | Kept | OBJ carries material colors, which is at least what 3DM stores, so the colors come across. |
| Layers and structure | Kept | Layers survive as real layers in the OBJ file, so you can still isolate and toggle them. |
| Units and scale | Dropped | OBJ stores no unit. Coordinates are written in meters, so set the import unit to meters if the destination asks. |
What the OBJ writer emits: OBJ plus a companion MTL, zipped together. Each layer becomes an object block and each mesh a named group with its material color.
The source: Rhino 3D Model (.3dm)
Rhino meshes, NURBS surfaces and polysurfaces, SubD, curves, point clouds, layers with their colors, and the file unit system.
The target: Wavefront OBJ (.obj)
The lowest common denominator of 3-D interchange. Practically every 3-D application reads it.
Opens in: 3ds Max, Maya, Rhino, Cinema 4D, Blender, MeshLab.
Your file never leaves your computer
Both the 3DM parser and the OBJ writer are JavaScript and WebAssembly running in your own browser tab. There is no upload step, no server-side conversion queue, and no copy of your file anywhere but your machine. That matters for drawings under NDA, for client work, and for anything you would not email to a stranger.
Frequently asked questions
▶Is this 3DM to OBJ converter free?
Yes. No signup, no watermark, no per-file limit and no paid tier. Innerscene.
▶Is my 3DM file uploaded anywhere?
No. The file is read with the browser file API and converted in the same tab. Nothing is sent to a server unless you explicitly click Share, which is a separate, opt-in feature.
▶Will my colors and materials survive the OBJ export?
OBJ carries material colors, which is at least what 3DM stores, so the colors come across.
▶Do layers and named parts carry into the OBJ file?
Layers survive as real layers in the OBJ file, so you can still isolate and toggle them.
▶Will the OBJ open at the right size?
OBJ stores no unit. Coordinates are written in meters, so set the import unit to meters if the destination asks.
▶How large a 3DM file can I convert?
Up to 200 MB, and the ceiling adapts to how much memory your device reports. The conversion runs on your own hardware, so a desktop with plenty of RAM will handle more than a phone.
▶Can I convert OBJ back to 3DM?
Yes, the other direction works too. Bear in mind that anything the first conversion dropped is not restored by converting back. OBJ → 3DM
▶Which browsers does it work in?
Chrome, Edge, Firefox and Safari, on Windows, macOS, Linux, iOS and Android. No plugin and no extension.
Convert 3DM to something else
Convert something else to OBJ
Or start from the universal 3D viewer.