When you download textures from model / texture websites, the texture set typically doesn't match what you need in Unity. You can use this utility to re-pack the texture set so that it matches the Unity default shader configuration.
Here's how it works:
- Open the Editor Window
- For each Output channel, select an Input Texture or pick a default value (Range: 0->1).
- Pick the Channel you want to rip from the Input Texture
- You can invert the channel if needed
- Bake and save.
Pretty easy, works, nice little utility.