Swarms

[Lord Pendragon]

From a DM point of view, I would be comforatable granting a 20 to 35% concealment with the same chance to block LOS.

So you'd be comfortable saying the bats have a 20 to 35% chance to completely block vision for a solid 6 seconds?

 

[billd91]

I'm actually quite content with blocking line of sight. This is a really large number of bats flapping around a fairly small area. Works for me.
Without the rules in front of me, I'd say it's quite reasonable for the flying swarm to block line of sight to anyone behind it, and grant concealment to anyone in it.

 

[Primitive Screwhead]

Comfort level

{Originally Posted by Primitive Screwhead
From a DM point of view, I would be comforatable granting a 20 to 35% concealment with the same chance to block LOS.}
So you'd be comfortable saying the bats have a 20 to 35% chance to completely block vision for a solid 6 seconds?

Think about your question for a second or two...please... and if in doubt, re-read the above.

 

[Lord Pendragon]

Think about your question for a second or two...please... and if in doubt, re-read the above.

I'm not sure what you're getting at. What say you just spell it out for me? Your post to which I was responding said you'd give 20-35% concealment, "with the same chance to block LOS." Since you're only giving a "chance" to block LOS, and the only percentages you offered were 20-35%, I figured you meant you'd give the bats a 20-35% chance to block LOS.

Now, I assumed this would change each round (i.e. each round you'd have to see whether the bats blocked LOS), and since a round is 6 seconds....voila! You seemed to be comfortable giving the bats a 20-35% chance of completely blocking LOS (which comes down to 100% concealment,) for a full round, or 6 seconds. This seems like a lot to me, so I asked my question.

Apparently you meant something different. What exactly then did you mean to convey?

 

[Primitive Screwhead]

Meanings and stuff

My apologies if my grammatical structure caused miscommunication. I have a habit off being consice is my wording, even when the subject of the message may benefit from a slightly more verbose effort.
Allow me to rephrase.

As a DM, I am comfortable with granting a 20 to 35% concealment to any creature in, or beyond, a swarm of bats due to the mass of mouse sized flying critters flitting about their squares. Use the normal ranged attack rules for applying concealment.

Also, I am comfortable with ruling that there is a 20 to 35% chance for any spell cast through the area occcupied by the swarm that requires LOS to the target, to have the LOS blocked by the swarm. The spell effect would occur at the point it is blocked, similar to the famous example of placing a fireball seed through an arrow slit. This chance can be avoided just as the concealment issue, via application of the ranged attack rulings.
Essentially, there is a chance at the time of any attack for a small mass of bodies to temporarily block the ability to see beyond them or for objects to pass through unhindered.

I am fully aware that this ruling affects the tactical use of Summon Swarm and needs to be considered when calculating some encounter ratings. I have not given enough consideration to the subject to determine the exact amount of a chance to apply.

Hopefully that better explains my meaning.

 

[Lord Pendragon]

Thank you Screwhead, that definitely clears things up.

 

[Abraxas]

In the game in which this came up the DM ruled that the swarm provided 100% cover (blocking line of effect and line of sight).