Headhunter,
I wish I could predict how a target buck is going to walk past me, but I can't. However, I do know how to play the odds. I hunt in an area where terrain is the predominant driver of deer travel patterns. And deer will use terrain in a somewhat predictable fashion. I say "somewhat" because deer will do things that defy the odds. But the critical factor is most of the time they walk along terrain in a certain way. So I play those odds when playing the wind. If most of the time they walk a long a ridge in a certain way, I want to be downwind of that travel line. Now that doesn't mean a deer won't approach from a completely different direction and wind me. That happens. But most of the time it doesn't.