How does sneaking work?

[Legacy_iso12000]

               

I know that it's the opponent's listen/spot vs your hide/move silently, but how exactly is it executed in the game? When my ranger enters stealth mode and starts sneaking around, the NPCs immediately face and start walking toward him. I know that combat hasn't started at this point because I see that initiative rolls haven't started in the dialogue box (and the combat music hasn't started either). It does start when they get right up to my face though.My hide and move silently are 11 and my ranger is level 4.

 

I don't know if I'm doing something horribly wrong or if the NPC's spot/listen/whatever is really high.

               
               

               
            

[Legacy_Terrorble]

               

http://nwn.wikia.com/wiki/Stealth

 

I think the NPCs may simply be detecting you at some point before you reach them (note the part about "opposed" rolls).  Or, you may need to activate stealth further away from them.

               
               

               
            

[Legacy_iso12000]

               

Thank you!