Fire Traps

How can I make it so whenever the fire side trap doodad shoots flames, it damages the units that are getting hit by the flame, but whenever it isnt shooting it, it doesn't damage the units inside the flame?

Ok, first of all let me point out one thing: There exist no way for war3 to know when a doodad's animation look like a flame and when it doesn't. To war3, the firetrap is just a static object. The flame you see spurting out from time to time is entirely visual. To repeat, doodads are almost nothing in the war3 engine.

What you CAN do however, is create a unit that uses the side-flame animation as a model. At the very instant you create it, it will play the "bursting flame" animation. About half a second later, the fire is invisible, only to repeat itself later.

So, when you create the unit (and it displays the flame for half a second) just deal damage to the units that happen to be where the flame hits. Then you remove your flame-unit and recreate it periodically whenever you want the flame to burst.

Got it? And can you think of a way yourself to decide where the flame hits?

Do I use a timer, do I use imolation so it kills the units that walk into it; if i do that will the unit be like this: (X is the unit)
0000000
000X000
0000000

or this:
000X000
000X000
000X000

You could just use a dummy unit to cast a carrion swarm with an invisible model that covers the area the fire is supposed to damage. (just make sure you cast the spell in sync with the fire).

Like make a trigger that every 2 seconds creates the fire model unit, then a dummy units that casts carrion swarm at the area (use a high missile speed) and waits 0.5 seconds and then removes the fire-model (so it doesnt restart its animation outside your control)

But whats the trigger to use, to make it cast the ability?
I've done fire and frost, how do I make it so it slows you down also(in the frost one)

I think the "Cone of Frost" ability should have a slow field.