Convert Rhino 5 to Rhino 3
Rhino 3 (released 2004) can't read files saved by Rhino 5 (2012) — a 2-version gap in the OpenNURBS archive format. This tool rewrites your .3dm from v50 down to v30 in seconds, translating newer object types to their Rhino 3-native equivalents.
Files will be converted to Rhino 3 (if compatible).
Why convert Rhino 5 files to Rhino 3?
You're modeling in Rhino 5 but need to hand the file to someone on Rhino 3 — a client, subcontractor, university lab, or team member who hasn't upgraded. Rhino 3 is still used by archived engineering files, and Rhino 5 is used by legacy studios, university labs, workflows tied to older plugins. Rather than asking them to upgrade or waiting for a re-export, convert the file here and send them a Rhino 3-native .3dm.
- Open Rhino 5 files in Rhino 3 without upgrading your license
- Official OpenNURBS 50 → 30 write pipeline
- NURBS surfaces, curves, meshes, layers and blocks preserved
- Runs in seconds, right in your browser — files stay private
- No plugins or software installation required
- Works on Windows, macOS and Linux
How it works
- 1
Upload your Rhino 5 .3dm file (drag & drop or browse)
- 2
We detect the file version instantly from the file header
- 3
Click Convert — the file is rewritten in Rhino 3 format using the official OpenNURBS libraries
- 4
The converted file downloads automatically
What actually changes between Rhino 5 and Rhino 3
Features introduced between Rhino 3 and Rhino 5 are downgraded to their closest Rhino 3 equivalent: clipping planes, refined history records, 64-bit-only object flags, Gumball transforms, and modern surface analysis data.
The archive header is rewritten from OpenNURBS v50 (Rhino 5) to v30 (Rhino 3) so Rhino 3 recognises the file natively.
Rhino 5 (2012) to Rhino 3 (2004) is a 2-version step. Core geometry survives cleanly; a handful of newer object types get flattened to older equivalents.
Geometry preservation
NURBS surfaces, curves, meshes, layers, blocks and materials are preserved. clipping planes, refined history records, 64-bit-only object flags, Gumball transforms, and modern surface analysis data are the ones that need translation: they get replaced with the closest Rhino 3-native representation (e.g. SubD → mesh or NURBS, newer annotations → base annotation types).
Tips for a clean Rhino 5 → Rhino 3 conversion
- Save a copy of the original Rhino 5 file before downgrading — some newer features can't be perfectly round-tripped back.
- If you're on Rhino 3 yourself and just want to hand the file to Rhino 3 colleagues, this is a one-click job.
- Rhino 3 predates modern annotation styles. Add dimensions and text after conversion in Rhino 3 rather than trying to preserve Rhino 5 styles.
Rhino 5 to Rhino 3 — FAQ
Can Rhino 3 open Rhino 5 files?
No. Rhino 3 uses OpenNURBS archive v30 and can't parse files saved with Rhino 5's newer v50 archive. Converting the file to the Rhino 3 format with RhinoFileConverter solves this in seconds.
What actually changes when I convert Rhino 5 to Rhino 3?
The archive version is rewritten from v50 to v30, and features that didn't exist yet in Rhino 3 — clipping planes, refined history records, 64-bit-only object flags, Gumball transforms, and modern surface analysis data — are translated to their closest Rhino 3-native equivalent, exactly like Rhino's own "Save As Rhino 3".
Will my SubD or ShrinkWrap geometry survive from Rhino 5 to Rhino 3?
Rhino 3 predates SubD (added in Rhino 7). SubD objects are converted to a mesh or NURBS approximation on the way down. If you need editable NURBS geometry, run ToNURBS on SubDs in Rhino 5 before converting.
Is my file uploaded to a server?
No. The conversion runs entirely in your browser using the official OpenNURBS WebAssembly build. Your Rhino 5 model never leaves your computer.
Is there a file size limit?
Free conversions support .3dm files up to 25 MB. Paid plans raise the limit to 200 MB (single) and 250 MB (unlimited) — enough for most architecture and product-design files.