title: How to use Graphic Raycaster with WorldSpace UI?
body: <p>I'm trying to figure out how Graphic.Raycaster works, but documentation doesn't  help. I want to use it to cast raycast from some position at a certain angle and hit the UI. The other thing is that I don't know how to make it interact with the UI(drag, click etc.). I know that's broad subject, but I just can't find any good explanation of how to use it, so I would be grateful for any explanation.</p>