[Spell] Hero ability AoE & DoT

[Haxerflaxer]

Hi! I've just started using the editor to create some fun maps for me and my friends and so far it's going great; except one encounter, which I seem to be unable to do and can't find any solutions on the world wide web.

I'm trying to create an ability for a hero which is more or less like the meat wagons attack. I want to make a turn on/turn off ability which drains mana and throws a chunk of flesh which will cause poison damage on the enemy and at the same time leave a timed area of poison which other creeps will get poisoned from if they step into it.

I can't seem to find an already existing spell that does that within hero unit abilities.
Is it something that is possible to do or should I just drop it?

 

[Jampion]

If I understand it correctly, your hero is a ranged hero and you want an ability similar to Searing Arrows or Frost Arrows, that deals damage over time and leaves an area of poison at the position of the attacked unit.

First you need to decide for a base ability. You should use Frost Arrows, because it applies a buff on the target. You should use a custom buff that is not used for anything else. If your ability needs multiple levels, you need to create a buff for every level.
With this buff, we can detect when a unit is hit by the ability. Once you know that a unit has been hit by the ability the rest should be pretty straight forward:
Use a dummy caster to apply the damage over time effect
Create poison unit at the target location (disease cloud also uses a unit for the cloud)

For detecting when a unit gets the buff you should use a damage detection system.