Alloy has a preview shader designed to work with Allegorithmic's Substance Painter tool to provide a mostly accurate preview of how the resulting material set will look in Unity 5 using Alloy.
- Go to your "Documents" folder and locate the "Substance Painter" folder.
- Navigate to "..\Documents\Substance Painter\shelf\shaders".
- Copy the "Substance Painter Custom Shader.zip" file from your Alloy project packages directory into the "..\shaders" folder.
- Extract the file contents here so that the "*.glsl" files are in this folder.
- Open up Substance Painter, and confirm that the "Alloy" shaders are available in your shelf.