How to convert the .unity3d web archives to .stl files for 3D Printing.

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The .unity3d contain a (sort of) compiled version of Unity3D assets in a generic form. We’re going to convert them back to Unity3d source assets, export those assets to .fbx then convert that to a .stl file. To do this “my way” you’ll need;

• uTinyRipper
• Unity3D
  • I’m using the 2020 LTS version
  • a minimal install with just Desktop/Editor stuff is fine
• the Unity3D FBX Exporter
  • you’ll need to install this through the editor. we’ll get to that.
• Blender
  • i’m using 2.91
  • the “Portable” versions are fine

Extract the Unity3D assets from the .unity3d file

Make a “web archive” folder with your .unity3d files in it. Make a second empty “ripped” folder to hold the extracted ones.

Launch uTiny and you’ll see a usual three-pane editor. Drag the .unity3d file into the uTiny editor (you can do only do one at a time) and it’ll get to work. Now click the “Export” button and select the “ripped” folder to save the data there.

Once the tool is done, you can close uTiny.

If something goes wrong, you’ll (probably) have to close and reopen uTiny.

Use Unity3D to create a .fbx file

Create a new empty Unity3D project.

Really Dave, create a new one. Don’t try to do this as part of an existing project.

Once that’s initialised;

1. open Window > Package Manager to open the package manager.
2. select Packages: Unity Registry
3. enter fbx in the search bar
4. press the Install button on the lower right

When that’s done, or while that’s working - copy the ripped folder into the project’s Assets/ folder. This should kick off Unity’s asset importer … so … there’s that.

When the import is done (and the exporter has installed the FBX Exporter) find the/a mesh or prefab and drag it into the open scene. It will likely be “pink” as in …

Roses are Red

Models are pink

Someone broke the

Materials I think

… but that’s fine if it has the correct silhouette. Set the “Shading Mode” to “Shaded Wireframe” if you want to check.

Right-click, in the scene, on the object and select Export To FBX ... and you can export this. You need to set Export Format to Binary so that Blender can read it. You should save it outside of the Assets/ folder so that Unit3d doesn’t try to import it … but there’s no real harm if that happens.

Once this is done, you can close Unity3D.

Convert with Blender3D

Open Blender, create a new 3D file/scene and delete the cube that the scene starts with.

You can delete the “Cube” by right-clicking on it in the top-right “Scene Collection” window

Use the menus to File > Import > FBX (.fbx) and select the file you exported from Unity3D.

Now, use File > Export > Stl (.stl) and save the .stl file as you wish.