Convert 3DM to OBJ
Rhino to OBJ, converted in your browser and written with a proper MTL file. Nothing is uploaded and nothing is stored.
What breaks when you convert Rhino 3DM to OBJ
The triangulation is permanent
OBJ stores triangles, and once your Brep has been converted there is no path back to the original surfaces — you cannot refine the mesh afterwards the way you can inside Rhino. Decide the mesh density before you convert, not after, because the OBJ is the end of the line for that geometry.
OBJ carries no units at all
There is no field in the format for them. Your Rhino millimetres become bare numbers, and whatever opens the file decides what they mean — which is why the same OBJ imports at wildly different sizes in Blender, Unity and 3ds Max. Use the output-units control above to pick the scale your target application expects.
MTL is a pre-PBR material format
It has slots for diffuse colour, specular colour and a specular exponent, and nothing else. A Rhino physically-based material with metalness and roughness has to be approximated into those three, so the material will read as broadly right rather than identical. We write the diffuse colour and base-colour texture; the rest has nowhere to go.
Layers become groups, and blocks are flattened
Rhino layers map onto OBJ object groups, which is close enough to be useful. Block instances are a different story: OBJ has no concept of an instance, so every placement is written out as its own full copy of the geometry. A model built from a few repeated blocks can grow enormously in the process.
Questions
- Do I get an MTL file too?
- Yes, along with any textures the materials reference. Download all of the files and keep them in the same folder — the OBJ points at the MTL by name, and the MTL points at the textures the same way.
- Why is my model the wrong size in Blender?
- Because OBJ declares no units and Blender assumes metres. If your Rhino file was in millimetres, set the output units above to millimetres or metres depending on what you want the numbers to mean, and check the dimensions we report after converting.
- Can I convert several 3DM files at once?
- Not yet — one model at a time. Batch conversion is one of the things a server-side version would add, but everything here runs on your own machine.
- Does this work offline?
- Once the page has loaded, yes. The conversion itself needs no network connection because there is no server involved in it.