# Free online 3DM (Rhino) viewer

> View Rhino .3dm files in your browser without a Rhino licence. Meshes, cached render meshes, SubD and blocks are shown in millimetres — free, no upload, no account.

Source: https://freestlviewer.com/3dm-viewer/  
Updated: October 22, 2026

Open Rhino .3dm files in your browser without Rhino. Meshes, saved render meshes, SubD objects and blocks are shown — nothing is uploaded. The tool is interactive: open https://freestlviewer.com/3dm-viewer/ and drop a file onto the page.

## What is a 3DM file?

`.3dm` is the native file format of Rhinoceros (Rhino), McNeel's NURBS
modeller used in industrial design, jewellery, architecture and marine work.
The format is documented and implemented by McNeel's open-source **openNURBS**
toolkit. A 3DM file can hold NURBS curves and surfaces, polysurfaces (Breps),
extrusions, SubD objects, meshes, blocks, layers, materials and annotations.

Sharing a 3DM with someone who does not own Rhino is a common headache: most
general 3D viewers do not open it at all, and Rhino's own viewer options
require installing software.

## How Mes3D reads 3DM

Mes3D uses **rhino3dm**, McNeel's WebAssembly build of openNURBS, the first
time you open a `.3dm` file (about 2.7 MB, downloaded once). It then collects
everything that can be drawn as triangles:

| Object type | What is shown |
| --- | --- |
| Mesh | The mesh itself |
| Polysurface / Brep, Extrusion | The render meshes Rhino cached in the file |
| SubD | A mesh generated from the subdivided control net |
| Block instance | The block's geometry, at every placement, nested blocks included |
| Curves, points, annotations, lights | Not shown (nothing to draw as a surface) |

The model's unit system is converted to millimetres when it is set in the
file, and object or layer colours are applied in the **Original** view.

## The render-mesh catch

Rhino stores NURBS geometry exactly, and keeps a triangulated **render mesh**
next to it for display. Mes3D, like most lightweight viewers, draws that cached
mesh. Two ways of saving leave it out:

- **SaveSmall** (or "Save small" in the save options) deliberately strips
  render meshes to shrink the file;
- some scripts and exporters write geometry without ever shading it.

If a polysurface you expect is missing, open the file in Rhino, switch a
viewport to Shaded or Rendered so meshes are created, and save normally. For
files you plan to share widely, exporting a copy as STEP (for engineers) or
STL/3MF (for printing) is still the most portable choice — Mes3D opens those
too.

## How to open a 3DM file here

1. Drag the `.3dm` file onto the drop zone above, or click **Choose 3D file**.
2. Rotate, zoom and pan; use preset views and orthographic projection for
   straight-on views.
3. Choose **Original** as the model colour to see object and layer colours.
4. On a computer, measure point-to-point distances in millimetres, read the
   overall dimensions, and open the analysis panel for volume, surface area
   and estimated weight — useful for jewellery and casting estimates.

## Who this is for

- **Clients and reviewers** who receive a `.3dm` and just need to look at it.
- **Jewellers and makers** checking a model's size and volume before casting
  or printing.
- **Teams** where only the designer has a Rhino licence.

## On a phone

A 3DM sent by email can be opened in a mobile browser here for viewing and
dimensions. The Mes3D app for iPhone, iPad and Android opens 3DM files from
Files or Mail and adds measuring, mesh analysis and cross-sections, and can
export the result as STL, OBJ or 3MF.

## Limits

- Up to 200 MB per file in the browser.
- NURBS surfaces without cached render meshes are not displayed (see above).
- Materials are shown as display colours; Rhino render materials, textures and
  lighting are not reproduced.

## Frequently asked questions

### How do I open a .3dm file without Rhino?

Drop it into Mes3D in any modern browser. It reads the file with McNeel's openNURBS library compiled to WebAssembly and shows the geometry in 3D, with measuring and dimensions. No Rhino licence or installation is needed.

### Why is part of my 3DM model missing?

Rhino's NURBS surfaces and polysurfaces can only be displayed through the render meshes Rhino caches in the file. If the file was saved with SaveSmall, or exported without render meshes, those objects have nothing to draw. Open the file in Rhino, shade the viewport so meshes are generated, and save it normally.

### Are layer colours shown?

Yes. Object display colours are read from the object, or from its layer when the object uses its layer's colour, and shown in the Original view.

### Is my file uploaded?

No. The openNURBS engine (about 2.7 MB) is downloaded once and runs in your browser; the .3dm file is processed locally.