.glb file fail to import to Unity

[DeepChallengerVR]

Issue

• OpenBrush .glb fails to import to Unity.
• On first time opening the unity project with added .glb files you will see below error message.
• Subsequent Unity project opens you will likely not see the below error message, but you will see your .glb files have not imported.

Error message
InvalidOperationException: Cannot find TiltBrushToolkitSettings.asset TiltBrushToolkit.TbtSettings.get_Instance () (at Assets/TiltBrush/Scripts/TbtSettings.cs:38)

Steps to reproduce

1. Have a .glb file exported via OpenBrush
2. Install this SDK in your Unity project
3. Import the .glb file and add to scene. Observe the file imports correctly and you can see the .glb model in your scene.
4. Copy and paste your Unity project into another directory, open this 'new' copy of your project.
5. Observe issue.

Workaround

• to make your life easier, in your Unity project keep all of your .glb / tiltbrush files in folders dedicated to tiltbrush files.
• For this example steps to fix, I assume all of your .glb files are stored in Assets/3dModels/TiltBrush
  Steps to fix issue when it appears:
• Copy the contents of Assets/3dModels/TiltBrush to somewhere on your PC outside of your Unity project
• In Unity, delete the contents of Assets/3dModels/TiltBrush
• Drag and drop the contents from Windows File Explorer back into Assets/3dModels/TiltBrush
• You should not see any .meta files changes and your local install of the unity project should not have this issue anymore.

This issue was originally logged on tilt-brush-toolkit with no resolution other than workaround googlevr#43