Is a Line of Sight Possible?

well, i can say i can't test this out. And i wouldn't knwo where to begin, i'm guessing some knowledge of triggonomatry or whatever would help alot.

Does anyone know how to go about this hopefully without Jass, or if jass just using a few call functions. This could be really intresting in an hunter and prey type map.

Depends on what you mean. To make it so that unit only see within a certain angle of where there head is aimed -- sure, with triggers. To make it so a little triangle appears like in Metal Gear Solid or whatever, is probably possible but would require custom models.

Hmm, well I made a Tenchu map which used a tenchu/metal gear solid style gameplay feature, but it was highly simplified in that you don't fight the enemy if you're discovered rather you're simply defeated. So it's all about looking around corners with wards and sprinting up behind enemies. The object is to be the first to reach the centre of the map and punish the evil merchant. I personally enjoy playing the map as you're placed in teams of two, but usually half of the people leave the game after dying. Anyway I'll post the map to show how it works. I used unit comes within range events for every player's hero and then move a region infront of the entering unit and check if the player is in the region or not, if so then of course the enemy can see you otherwise it can't and then a stealth kill animation plays. There's 3 different heroes, one for each hero attribute, higher strength allows for quicker revival times, agility increases movement speed and intelligence works just like normal. I'm hoping you're question was leading towards a stealth style game...otherwise my map doesn't really suit you.