3MF Viewer for macOS
====================

A lightweight, native Mac app for viewing 3MF files (.3mf) — the 3D format
used by Bambu Studio, OrcaSlicer, PrusaSlicer, and most modern slicers.

Once installed, it adds three things to your Mac:

  • Finder thumbnails — .3mf files show a little 3D preview instead of a
    blank document icon.

  • Quick Look — select a .3mf file in Finder and press the Space bar to get
    an interactive 3D preview you can spin and zoom, right from Finder.

  • A viewer app — double-click a .3mf file (or drag one onto the window) to
    open it in a resizable window.

It renders everything natively, handles multi-color models, and opens large
slicer files quickly. It runs entirely on your Mac — no data is collected and
it never connects to the internet.


Requirements
------------
  • macOS 14 (Sonoma) or later
  • Any Mac — Apple Silicon or Intel (universal binary)


Installing
----------
  1. Unzip the download, if it hasn't already unzipped.
  2. Drag "3MF Viewer.app" into your Applications folder.
  3. Open it once (see the note below the first time), so macOS switches on
     the Finder thumbnail and Quick Look features.

Keep the app in your Applications folder — the thumbnail and Quick Look
features only stay active while the app lives somewhere permanent.


First launch: the "unidentified developer" warning
--------------------------------------------------
3MF Viewer is free and isn't yet signed with an Apple Developer certificate,
so the first time you open it macOS shows a caution that it "cannot be opened
because Apple cannot check it for malicious software." This is expected for a
free app distributed outside the App Store — nothing is wrong. Here's how to
open it:

  Method 1 — Privacy & Security settings (recommended)
    1. Double-click 3MF Viewer. You'll see the warning; click Done/Cancel.
    2. Open  System Settings → Privacy & Security.
    3. Scroll down to the Security section. You'll see a line saying
       "3MF Viewer was blocked to protect your Mac." Click "Open Anyway".
    4. Confirm, and use Touch ID or your password if asked.
    5. It opens — and won't ask again.

  Method 2 — Terminal (if Method 1 doesn't show an "Open Anyway" button)
    1. Open the Terminal app (in Applications → Utilities).
    2. Paste this and press Return:

         xattr -dr com.apple.quarantine "/Applications/3MF Viewer.app"

    3. Now open 3MF Viewer normally.

(On older versions of macOS you can also Control-click the app and choose
Open. Recent versions use Method 1 instead.)


Using it
--------
  • Thumbnails: .3mf files show 3D previews in Finder automatically. The very
    first time, give it a moment — or close and reopen the folder.

  • Quick Look: click a .3mf file once and press the Space bar. Drag to
    rotate, pinch or scroll to zoom, two-finger drag to pan.

  • Open in the app: double-click a .3mf file, or drag one onto the window.
      - Drag           rotate
      - Pinch / scroll zoom
      - Two-finger or  pan
        Option-drag
      - Flat / Smooth  shading toggle, in the toolbar


Uninstalling
------------
Drag "3MF Viewer.app" from your Applications folder to the Trash.


About
-----
Free to use — see LICENSE.txt for the terms. It's currently unsigned; if people
find it useful I'll look into having it signed and notarized by Apple so the
first-launch warning goes away. Feedback is welcome.

Version 1.0
