Question about angles etc.

[oorosco]

Can someone explain to me the process of finding units off in a certain angle of a chosen unit, such as if i wanted to find units behind a certain unit, or in front, etc. (Because offset is just depended on which way it is facing) Thanks!

 

[Exide]

There's a tutorial about attacking units from behind (like Stealth Assassin's backstab ability, from Dota.)

Here:
Tutorial