i understand how the smart sytem works. u run to an object and u can slide under it or vault over it. but i noticed in almost all teh vids your able to slide without being near an object. how will this affect shooting if your gunna have to look where ur going? as in, if i look down and people are shooting at me, if i look up to shoot, wont i pop up from sliding? also are there combos or a cooldown time for smart? like can i do 6 vaults really fast over railings or is their like a second delay?

I think it's a combination of buttons to perform a slide. I know people who had the chance to will be able to give you a decent answer on this matter.
While sliding, you will be able to shoot, so my guess is that you have to press "lower stance button" + SMART button to do the slide, while you can freely look around and take people down.

Normally there's no time delay between actions to make you move smoothly (SMOOTH MOVEMENT across random terrain) However, the time you need to perform certain actions depends on bodytypes, current movement speed/momentum and they way you approach the object you want to climb over.
I suggest you read http://brinkthegame.com/community/blogs/detail/?id=4 to get a better view on what I'm trying to explain.

i understand how body types affect how you move. i have read pretty much everypeace i could on the smart system. unfortunatly i live in teh US so i was unable to play at this years Eurogamer. also their is a crouch button and a smart button?

I didn't play it either, just using common sense ^^

Their has to be a crouch button. The SMART button is more or less the sprint button in other games, you should be perfectly capable of using them at the same time the gain the "combo-effect" of a slide. Atleast that's how I think it is. I think REVOLUZZER can confirm this, since he played the game.

There is the SMART/Sprint button (LB on XBox) and the Crouch Button (B on XBox). While sprinting, you can use Crouch to perform a (tackle-)slide. While sliding, you're able to shoot. However, it's really hard to aim while sliding (because it's really fast) and as you're holding LB already, you can't ADS with LT that easy.

Tnx for clarifying this. I already suspected that it would work this way.