How to make a smooth blight

[Majin]

I want to make a spell that temporary creates a blighted area (like desecration in wow), but i'd like the blight to be created smoothly and not all at once (which is what happens if you use the SetBlight() function), also the blighted area has to disappear once the spell ends, except where it was already blighted before the spell.

The only idea i had to do this was to make several regions and use the SetBlight function on all of them, one by one, checking if the area is already blighted or not (if it is, it'll set some variable to 1 so it won't get removed once the spell ends), but i'm hoping in something simplier

Any ideas on how to do that? i was thinking maybe to use doodads or locusted unit that will emulate the blighted terrain, but i don't think it's possible (though it would've been better than creating blighted terrain)

 

[Bantas]

What about using the undead buildings' ability to create blight around them ?

 

[Majin]

which is as smooth as using a loop with a timer and creating blight in bigger areas (which is what at the moment i'm using)

 

[takakenji]

and thus making smooth blight does not exist.

 

[Majin]

it exists, at least in theory (haven't tested)...i'm just hoping there's an easier way