Hi all.

I've searched on forum why sometimes units under swarm were getting hit by Tanks splash and sometimes they didnt.

Any answers?

Because the tank's main attack won't go through but the splash damage will.

Ok...... I've seen a lot of replays of tanks splash on lurkers and they don't get dmg.

Splash hits burrowed units. Toss attacks their own zealots(the zealot being ontop of lurker) with archons to kill lurkers all the time.

Units with a ranged attack targeting a unit under dark swarm always miss. For units with splash damage, the center of the splash damage of the missed attack is a certain distance away from the target towards the attacking unit. This distance is just enough that a burrowed lurker under dark swarm won't take damage from a sieged tank. Unburrowed lurkers have slightly larger sprites (or maybe burrow interacts weirdly with splash damage, I'm not really sure), and will take damage. Also, if the missed shot is close to a different lurker than the tank was targeting, that lurker will take damage.

Great! Thank you for that answer Kyadytim.

It is much simpler.

A unit that is the target of a tank shot does not receive splash damage. This is it.

This means if you have only one unit under a swarm, it cannot die to tanks. Burrowed lurkers also do not receive damage from tank splash. But if you have 3 lurkers under one swarm and unburrow one of them and a tank shhots at one of the other two, so the unburrowed one will be hit by splash.

There was a thread about on teamliquid about dark swarm that answers your question:

Link Text

Dark swarm means the attack always miss and land a few pixels CLOSER to the attacking unit. A small unit, zergling instance, standing still in a dark swarm, a siege tank will never kill it. An unburrowed lurker is bigger, so the tank splash still hits part of the lurker sprite. Another big thing is whether or not you are running TOWARD the tank. Notice sometimes when tank fires at a running zergling, the fire lands BEHIND the zergling? Coz it's running foward. In side a dark swarm, if you are running toward the tank, it means you run right into the splash that's in front of you and takes damage.

I'm pretty sure the damage is applied at the start of the damage animation and not at the end.

Lets get this straight.

1. All ranged units miss when firing upon units under the dark swarm. The exceptions are as follows, firebat, lurker, reaver.

2. All melee units do full damage under a dark swarm. The exception is workers who do no damage under the dark swarm.

3. All magic (irradiate, plague, stasis, do I really have to list them all? I hope not.) works 100% under the dark swarm.

4. Splash still works under the dark swarm. If it is delivered in a line (firebat, lurker) there is no change to the damage. If it delivered by a missile the missile will land 0.5 matrices before the target unit, i.e. between the attacker and the attackee. The splash will the do full damage according to what it usually does in the new area it landed.

The upshot of rule 4 is that units that do splash damage delivered in a missile form (tanks, archons) do less damage to units under dark swarm since the splash is not in an ideal location.

The upshot of the upshot is the special case lurkers. When they are unburrowed inside a dark swarm the tank shot misses them but still does damage as their hit box is large enough to be hit by the splash. However when they burrow the lurker hit box shrinks in size. This should still be fine for tanks as tank splash is bigger than 0.5 matrices.

Now for the weird stuff. The lurker actually does not take damage. Whether this is intentional or a bug i do not know. What happens is the hit box for the lurker shrinks as it burrows, however the tanks still miss according to the old lurker hit box. When the reduced hit box is combined with the 0.5 miss of the dark swarm the lurker actually takes no damage WHEN THE TANK IS SHOOTING DIRECTLY AT IT. If the tank is shooting at something behind the lurker it might still do damage to it and kill it.

I hope there will be no more confusion about dark swarm mechanics.

Post edit: I feel i should include a couple more things to be complete.

-Dark swarm has absolutely no affect on building other than making them miss shooting units under the dark swarm (cannons, bunkers)

-The dark swarm is actually a square occupying a 6x6 matrix area.

-It has a casting range of 9 which means that when added to the area of the dark swarm defilers can cast it out of range of everything including siege tanks.

-dark swarm has indeed been verified to be 'completely imba"

-Reaver splash is not delivered in a line or by a missile. Rather it is delivered by a unit, the scarab. It applies full damage and splash when fired under a dark swarm. It has a damage of 100(125 upgraded), a range of 8, and a splash range just short of ludicrous. Reavers have been verified to be even more imba then dark swarm when "the stupid AI works" which is never.