add mana cost through triggers?

I made a ability called multiarrow based of barage, and no matter what I put under the mana fields, it still cost 0 mana. This skill is cheap omega, and I need it to cost mana somehow.
I tried unit cast ability
condtion: ability = to multiarrow
action: set mana of triggering unit to mana of triggering unit -1.
Also theres a bug where you need it to at least shoot 2minimum targets. It would be cool if the extra arrows did %based damage, but I cant do that :(. Also writting -15dmg in the damage field dont seem to do anything either. So is it possible to add mana cost through triggers?

You could maybe base a dummy spell off of immolation that does 0 damage and then set triggers to add the Barrage spell to the hero when the ability it activated and remove it when its deactivated.

If i add the ability, it being passive wont matter if cant fit in any button position does it? Cause all my heros have 6 abilities and have no room for more buttons

I actually had problems with adding abilities, then removing them from a hero... I might suggest you create an invisible unit, add the ability to the new unit, order the new unit to cast the ability, and remove the new unit from the game.

Edit: oops sorry I forgot what barrage did... forget everything I said.

:(. Darn, this skill is so overpowerd, and adding a mana cost is the only thing I can think of, I wish there way a way to make it an autocast ability :(.

still no responses?

Cool I havnt tried it yet but I think I found a way, kinda odd but not being a gosu map map maker like most of you here ive got to try it.
Event: unit is attackd
condtion: owner of attcking unit has 1lumber
action set mana of attcking unit to mana of attacking unit -1

then just make a trigger when I learn multiarrow add 1lumber, I have no use for lumber so it dont matter, however I just thought of something, is there a way to disable resource sharing? on just lumber though? Or nvm Ill just use an interger variable or somthing. ARG ! I want this skill to cost mana !. however by doing this no matter wht it cost mana, even if only 1unit is hit :(, spells such as stormbolt wont count as unit is attackd will it?

i have this same spell and i also have the same overpowered problem. first off ur trigger would work but don't make it one lumber. make it triggering unit knows hero ability multiarrow. of course you would have to know a little jass or have an advanced editor like we unlimited. but i tell you what i will make the trigger to cost mana and i will let you know how i did it. i know i can i just haven't actually tried. i was going to get to that part later. if i don't post it ne time soon pm me to remind me. i tend to forget things sometimes.

cool, tanks :). I dunno anything about jazz at all, and I dont have we unlimited anymore, ever since FT I just use that now, it seems to do everything. Theres no possible way to make it autocast right? cuz that is what I want most, also the amount of arrows still seems to be a tiny bit buggy

make ability yet? :)

1)event: unit cast ability
condtion: ability = to multiarrow
action: set mana of triggering unit to mana of triggering unit -1.

i had same problem with some trigger you should put:

event:
unit begin casting an abilty
condition:
casting unit = (name of your hero)
ability cast = multiarrow
action:
set mana of casting unit to (mana of casting unit - 1)

this way it will cost only 1 mana each time u use it (well it should for i have tryed only on roar based spell and other similar to roar)

2) Event: unit is attackd
condtion: owner of attcking unit has 1lumber
action set mana of attcking unit to mana of attacking unit -1
this way the units isn't using an ability??
event:
unit is being attacked
condition:
owner of attacked unit = ( name of your hero)
color of owner of attacking unit = black (or whatever unused color by player)
action:
set mana of attacking unit to (mana of attacking unit - 1)

instead of giving one lumber just change the color (easy :p )
but i am pretty sure the first trigger should work try it please.

nope didnt work :(

Would there be any other spell I could edit to get the same effect?

That trigger didnt work becuase barrage isnt an ability that can be cast, its passive. I still think you should try the immolation as a dummy spell and have a trigger that adds and removes barrage from the character. Since its passive you could make it appear on a spell space that already contains a passive skill or put it on the skill learn button which should put it under it and will only be visible if the player reaches his max level and uses all his skill points.

Ok ya thats what im going to do, I got some1 to help me out however I ran into a problem, I need a action that says
action: add(multi arrow points) to multiarrow.
I have a variable thats an integer that goes up +1 every time I learn dummy spell that way it keeps track of the level. How do I action: add (multi arrow points) to multi arrow then also the other way around.
action: add (multi arrow points) to dummy spell. Also how will I get the target? I need somthing like get last target