Need help with a trick problem

[Lady MufflaN]

I need a way to check if a unit ( a boss in this case ) is aggroed.

Secondly I need a way to create a obstacle at a special place that expires.

The idea is of course to make a encounter non escapeable for the heroes, there are several places they could tank a boss at a well, quite meaningless as it's now, thus I want to prevent them from escaping, any good suggestions?

 

[Exide]

Aggroed? = Attacked?
There's an event:
A unit is attacked - under Generic unit.

Obstacle, does it have to be visible? If not, you can use pathing blockers - awesome for blocking. (Can block either Air or Ground OR Both, depending on which you choose. )
Else just use a doodad?

EDIT: I find using a simple door (destructible) great for blocking paths, such as "boss rooms". Don't forget making it invulnerable, though.

 

[Mr.Tutorial]

Aggroed? = Attacked?
There's an event:
A unit is attacked - under Generic unit.

The problem with that is you don't have to attack a creep to aggro it.

 

[Exide]

A unit is attacked
Answers to the event 'attack unit'. -Triggering Unit doesn't need to take damage. Which would be great if there was an 'Unit Takes Damage' event, which there isn't as far as I know.

 

[Lady MufflaN]

Aggroed? = Attacked?
There's an event:
A unit is attacked - under Generic unit.

Obstacle, does it have to be visible? If not, you can use pathing blockers - awesome for blocking. (Can block either Air or Ground OR Both, depending on which you choose. )
Else just use a doodad?

EDIT: I find using a simple door (destructible) great for blocking paths, such as "boss rooms". Don't forget making it invulnerable, though.

Give me an example on how to block the red area in the picture attached

 

[noworries]

To block a single line like such in the picture you provided, all you really have to do is use a loop to create the pathing blockers in a line, adding # amount to the X offset each time.

For each (Integer A) from 1 to 8, do (Actions)
    Loop - Actions
        Unit - Create 1 Peasant for Player 3 (Teal) at ((Position of Farm 0105 <gen>) offset by ((Real(Count)), 0.00)) facing Default building facing degrees
        Set Count = (Count + 80)

I used Peasants so I could actually see it happening, and that has leaks. Anyways, in the pictures I'll provide, I have a distance of two farms. The base for creation is the farm on the left.

To find the best amount of distance between the peasants or blockers, I highlighted over each of the farms in the editor and got their X values, I rounded, it was 1400 for the one of the left, and 2200 for the one on the right, which left with me a range of 800 between them. Add in that 160 of those are unreachable(position from center of farm to outside was around 80 as well) so I used 8 loops increasing at 80 a piece, with the count variables initial value starting at 80.

Farms without peasants:
http://img.photobucket.com/albums/v325/noworries777/line1.jpg

Farms with peasants:
http://img.photobucket.com/albums/v325/noworries777/line2.jpg

If this made no sense then I'm sorry and will try better explaining. I don't do a very good job.

 

[Lady MufflaN]

Well actually, I solved it by making a invisible force wall that is 3 times it's own size, and whenever a boss fight ended, I'd just destroy "last created destructible"

 

[Exide]

There are many ways of blocking a path. The easiest way (imo) is to use pathing blockers (since that's what they're in the game for, in the first place). I would add and remove them by triggers. (Obviously. )
Apparently a force wall works as well. -One thing, though. Don't use (Last Created Destructible), use a variable. Or it might be lost by other triggers and the players would be trapped.