Questions about the heal ability

When settning the heal ability heal amount to a negative number it becomes a cool attack ability, but there are a few problems like:
1. You canoot cast heal on a unit that has full health, even if it does negative healing.
2. You can activate auto-casting.....I've had this problem many times before, How do i stop the user from activating an auto-casting ability?

You cant, look for a non-autocast ability. Heal isnt a great basespell to use as damagespell. Try another one :P

hmmmm...just my luck.

Are there any other abilities that mimic it? (having repeated cast)

Repeated cast?
That's auto-cast, right?

Try Rejuvenation.

Also, triggering a damage effect on a spell isn't that hard.

Are you asking for an auto cast damage spell? In that case i can suggest Searing arrows with no missile, no missile speed, instant attack and a art on the target.

I would use Faerie Fire and trigger damage

Hum, that wouldn't be a great idea, because Searing Arrows doesn't deals direct damage; it just boosts your attack damage.

you can also see the ability to not be able to cast it on a unit that has full hp as a pro, it gives the ability extra flavor. Personally i love a damaging heal, like Open Wounds in tides of blood. Simple set the amount healed to 0 and trigger the damage though.

what I ment with repeaded cast was the way heal is automaticly casted over and over again.

The hole point of using it was that the unit does not have an normal attack. So the damaging heal ability is sort of an attack ability with cooldown.

Not aving an attack sora rules out the searing arrows abillity

Heal won't auto-cast on enemies. Many a newbie failed to realise that on Tides of Blood...

But if you do cast it on a target, it carries on casting it on the target until you give another order.

Use erwt's suggestion, and make it heal 0 and trigger the dmg.

You are not making a hell of alot of sense.

If you don't like the carry-on-till-ordered-not-too behavour, use ANY OTHER DAMAGING ABILITY instead.

If you do like that behavour you can prolly use (as suggested) a 0.01 duration 1 cooldown fairie fire and trigger the damage. This also gets around the max hp problem.