Cookies for analytics and advertising
We use cookies for analytics and advertising, both sent to Google. Refusing changes nothing you can see.Read the privacy page
3MF
What is a 3MF file?
The modern replacement for STL. Keeps colour, materials and units instead of bare triangles.
What 3MF is
3MF is a container: a wrapper that holds streams encoded by something else. It stores shapes and coordinates rather than pixels, so it stays sharp at any size — a logo scaled to a billboard loses nothing. It is used for 3D printing.
The extension is .3mf, and the full name is 3D Manufacturing Format. Both matter less than what the file can hold, which is what the rest of this page is about.
Where 3MF came from
3MF Consortium published it in 2015. The specification is 3MF Core Specification.
Age is worth knowing here for one practical reason: the older a format is, the more programs have had time to learn it.
The specification is public
Anyone can implement it without asking permission or paying a licence, which is why it turns up in so many programs and why files written twenty years ago still open.
Nothing is thrown away
3MF stores its content exactly. Saving it again changes nothing, so it can be opened, edited and re-saved as often as you like without accumulating damage — which is what makes it a working format rather than a delivery one.
What opens 3MF
PrusaSlicer, Cura and Microsoft 3D Builder read it, and so do most programs of the same kind.
If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.
Opening it in a browser
No browser reads it.
That is the single most common reason to convert it: not that the format is bad, but that the place you want to show the file cannot read it.
It is a working format
3MF is meant to be opened and changed. Keep the file in this format for as long as the work is going on, and export from it whenever a finished copy is needed.
The facts, in one place
| Extension | .3mf |
|---|---|
| Media type | model/3mf |
| Published by | 3MF Consortium |
| First published | 2015 |
| Specification | 3MF Core Specification |