Installation
1. Download and unpack the Umbra Package
Find the zip-file and unzip it
2. Import the Umbra package
Import the .unitypackage into your Unity project from Assets --> Import Package --> Custom Package.

3. Click Import in the pop-up window
*(N.B. This window sometimes disappears behind the main Unity-window.)*

4. Access the Umbra Computation GUI the Umbra menu item
Open the Umbra GUI to begin the fun!
