How to open a Rhino .3dm file without Rhino
A .3dm is a model from Rhino (Rhinoceros 3D), the modeller architects, jewellers and product designers use. If a designer sends you one and you don't own Rhino, neither Windows nor macOS will open it. Here are five options. (We make Xiaoer Omia (xiaoeromia.com), option 4 — the others are described as fairly as we can.)
Last checked: October 2026
1. Rhino's free 90-day evaluation
McNeel offers a fully working evaluation of Rhino for Windows and Mac.
- The real program: every curve, surface and layer exactly as the designer saw it.
- After 90 days, saving and plug-ins stop working unless you buy a licence; a big install to look at one model.
2. A web 3D viewer
Free sites such as Online 3D Viewer (3dviewer.net) list .3dm among the formats they open in the browser.
- Free; nothing to install.
- Needs an internet connection; for client or unreleased designs, check how the site handles your file first; layers and units may be shown only partly.
3. Blender with the import_3dm add-on
A free community add-on lets Blender import Rhino models.
- Free; once imported you can render or edit the model.
- Installing the right add-on build for your Blender version takes some care, and Blender is a lot to learn for a quick look.
4. An offline 3DM viewer: Xiaoer Omia
Xiaoer Omia (xiaoeromia.com) is a desktop viewer for Mac and Windows. Drag the .3dm in to rotate, zoom and pan it; the corner shows the model's size and units. Objects are coloured by layer or object colour, blocks sit where they belong, and hidden layers stay hidden. It reads the file with McNeel's own rhino3dm library, offline. Nothing is uploaded.
- No Rhino, no account, works offline; the same app opens STEP, STL, SketchUp, DWG and 150+ other formats.
- View only: no editing and no export. Files up to 128 MB. Files saved as "small" without render meshes show as wireframes. 3DM is a pro format: 5 free opens, then $19.90 once.
5. Ask the sender for an export
Rhino can export to OBJ, STEP, STL or PDF, formats that far more apps open.
- Free for you; the export opens almost anywhere.
- You depend on the sender, and you lose layers and Rhino-specific details.
Side by side
| Mac | Windows | Works offline | Shows layers | Cost | |
|---|---|---|---|---|---|
| Rhino evaluation | Yes | Yes | Yes | Yes | Free for 90 days, then paid |
| Web 3D viewer | Browser | Browser | No | Varies | Free |
| Blender + import_3dm | Yes | Yes | Yes | Yes, as collections | Free |
| Xiaoer Omia | Yes | Yes | Yes | Layer colours, hidden layers stay hidden | 5 free opens, then $19.90 once |
| Export from the sender | Yes | Yes | Yes | No | Free |
FAQ
How do I open a 3DM file without Rhino?
Use Rhino's free 90-day evaluation, a web 3D viewer, Blender with the import_3dm add-on, or a desktop viewer such as Xiaoer Omia (xiaoeromia.com), which opens .3dm offline on Mac and Windows.
Is there a free Rhino viewer?
Rhino's evaluation is free for 90 days, after which saving stops working. Web viewers such as Online 3D Viewer are free. Xiaoer Omia opens your first 5 .3dm files free, then costs $19.90 once.
Can I open a .3dm file on a Mac?
Yes. Rhino has a Mac version, web viewers run in any browser, and Xiaoer Omia is a native Mac viewer that opens .3dm offline.
Why does my 3DM file show only lines?
The file was probably saved without render meshes (Rhino's "Save Small"). Viewers that rely on those meshes then show the model as a wireframe. Ask for the file to be saved normally, or for an OBJ or STEP export.
Can Xiaoer Omia open Grasshopper files?
Yes, it shows a .gh definition's components, wires, slider values and the preview the author saved, read-only. It doesn't run the calculation; the resulting geometry still needs Rhino.
Can I convert 3DM to STEP or STL without Rhino?
Blender with import_3dm can import the model and export STL or OBJ. Viewers, including Xiaoer Omia, don't convert. For STEP, ask the designer to export it from Rhino.
Related: 3D model viewer · How to open a STEP file · How to open a SketchUp file · How to open a .blend file · All guides · 150+ formats in one app