G-code (Numerical Control) .nc
The CNC spelling of G-code. Same commands, machining dialect.
What an .nc file holds
An .nc file is G-code under the name CNC machining has always used for it, numerical control. The command vocabulary is the same as a 3D printer’s, though the dialect leans on tool changes, spindle speeds and coolant rather than extrusion. Like any G-code, it describes a path a machine will follow, not a shape.
Commonly seen in: Fusion 360, Mastercam, LinuxCNC, GRBL, Haas controllers.
| Data | Stored in NC |
|---|---|
| Geometry | No |
| Materials and colour | No |
| Texture maps | No |
| Animation and rigs | No |
| Scene hierarchy | No |
| Read here | Yes |
| Written here | No |
Tested against a real file
The last sweep loaded benchy.nc from three.js examples, renamed with its 1 sidecar files through the viewer on this site: 0 triangles across 0 meshes and 2 materials, in 2.0 seconds. Every format's result is on the test results page, run 2026-09-08.
Convert NC to another format
Every pairing has a page saying what survives the trip.
Other things to do with an .nc file
Questions about NC
How do I open an .nc file?
Drop it into the viewer on this site and it opens in the browser, with the scene tree, the materials and the mesh statistics. Nothing is uploaded. If you want it in another program instead, convert it to GLB, which almost everything reads.
Is NC a good format to archive in?
NC stores . Anything outside that list will not be in the file at all, so archive the original alongside it if the surfacing or the rig matters.
Does converting NC lose quality?
Geometry is copied vertex for vertex, so the shape does not degrade. What gets lost is whatever the target format has no field for: convert to STL and the materials go, convert to OBJ and the animation goes. The comparison table on each converter page says exactly which.
Formats that hold the same things
Or go back to the full format reference.