Area affect spells and their affects on area [Archive] - Wizards Community

Area affect spells and their affects on area [Archive] - Wizards Community

Post/Author/DateTime Post
Xyplex
03-07-04, 09:28 PM Ok, I was thinking this morning about the environmental effects of dedonating a fireball in a standard D&D setting, but more importantly how much affect it would have on the surroundings (to be specific I was thinking of ways that a society would respond to spread spell effects ... metal doors that would close over arrow slits, and covered parapets, etc.)

Anyway, using the numbers from the "Stronghold Builders guide" I pulled out these numbers for packed Earth - Hardness 2, 10 HP / foot per 10 x 10 area ... so a standard Fireball, say 5d6, doing on average 17 points of damage ... divided in half to (rounding down) 8 points, minus 2 points of Hardness, would do 6 points of damage to the earth.

Now I envision it burning off the top 3/5 of a foot, or about 7 inches.

Area affect spells, by their nature, apply their damage and force over the full area, not to a specific point like a direct attack against an object like a battering ram. So when a Fireball doesn't do enough damage to break through an object, it stands to reason that the damage that it does do is spread evenly over the surface of the object, weakening it against further damage.

In my own mind, this realiziation makes a big difference. Using Fireballs in one's own castle to defend oneself might sound like a great idea, until you blow the doors off their hinges, crumble the rock (a 5d6 Fireball wouldn't be able to damage stone, on average, but a 10d6 Fireball would shave off, on average, half an inch off of every stone surface that you have), and indescriminately light fires, melt goods ...

The numbers in the PHB, DMG, and Stronghold guide all suggest these are the damages required to breach an object ... what are people's thoughts on this? It may not come up very often, but a savy spellcaster would pick up Sonic or Acid based spells (or energy substituion) and start blowing up a lot more than the opposition.
Escef
03-07-04, 09:53 PM The question is "What does the damage actually do to the object?". A fireball does not necessarily "shave off" anything. Since a fireball expands with negligable force, it couldn't blow the doors off a hamster cage. It can melt metal and stone (I'd include earth/soil in that catagory), incinerate anything it deals enough damage to that would destroy it, burn and blister flesh, boil liquids, and little else. Being of instantaneous duration, it can't even ignite fires technically.

Also, dealing enough damage to an object to destroy it does not simply make it vanish. A sundered sword can be reforged, a hinge that takes all the damage it can take will be a twisted, useless thing, but still there, etc. When a structure takes fatal damage it means that its structural integrity is gone. That could mean that something blew it apart, or that after taking so much damage it collapsed under its own weight.
badger3k
03-07-04, 09:56 PM Personally, I wouldn't use it unless the attack was directed against the wall/floor/whatever. Mainly for reasons of speed - if you want to calculate how much damage a wall takes when a fireball explodes nearby, you can. For me, its enough to say that the furnishings are on fire and the wall is scorched.

Now if the spell is specifically targeted to the wall, to breach it, then I'd determine the damage normally. Then there is a game-reason for it. Unless you want to have a lot of combats where the players have walls fall over, the floor drops away (well, really, the spell would either melt the dirt (?) or cause it to splatter around like a bomb explosion). I don't think the heat is enough to incinerate dirt to ashes, then take care of them too, not if there is anybody who is alive inside it.

The other option is only use such things when it's dramatic - the floor is wooden, and over a long, long fall, or they need to attack over the wooden bridge (or stone even), and it could be dramatic to have the bridge damaged. Or else they use fireball and cone of cold in an area in rapid sequence, where the heat and cold can cause stone to shatter. Unless that was towards the wall, though, I'd probably just say that splinters of rock fly off the wall and leave it at that.
Loren Pechtel
03-07-04, 11:34 PM I don't think a fireball would do anything more than cosmetic damage to earth or stone. I don't think it would transfer enough heat to melt enough material to actually cause it to flow away. The surface would be somewhat melted, images would be burned off etc, but I think you could throw them every day for a century without seriously eroding the walls.

On the other hand, try throwing them around in a wooden city and you'll certainly see some effects!

Post/Author/DateTime	Post
Xyplex 03-07-04, 09:28 PM	Ok, I was thinking this morning about the environmental effects of dedonating a fireball in a standard D&D setting, but more importantly how much affect it would have on the surroundings (to be specific I was thinking of ways that a society would respond to spread spell effects ... metal doors that would close over arrow slits, and covered parapets, etc.) Anyway, using the numbers from the "Stronghold Builders guide" I pulled out these numbers for packed Earth - Hardness 2, 10 HP / foot per 10 x 10 area ... so a standard Fireball, say 5d6, doing on average 17 points of damage ... divided in half to (rounding down) 8 points, minus 2 points of Hardness, would do 6 points of damage to the earth. Now I envision it burning off the top 3/5 of a foot, or about 7 inches. Area affect spells, by their nature, apply their damage and force over the full area, not to a specific point like a direct attack against an object like a battering ram. So when a Fireball doesn't do enough damage to break through an object, it stands to reason that the damage that it does do is spread evenly over the surface of the object, weakening it against further damage. In my own mind, this realiziation makes a big difference. Using Fireballs in one's own castle to defend oneself might sound like a great idea, until you blow the doors off their hinges, crumble the rock (a 5d6 Fireball wouldn't be able to damage stone, on average, but a 10d6 Fireball would shave off, on average, half an inch off of every stone surface that you have), and indescriminately light fires, melt goods ... The numbers in the PHB, DMG, and Stronghold guide all suggest these are the damages required to breach an object ... what are people's thoughts on this? It may not come up very often, but a savy spellcaster would pick up Sonic or Acid based spells (or energy substituion) and start blowing up a lot more than the opposition.
Escef 03-07-04, 09:53 PM	The question is "What does the damage actually do to the object?". A fireball does not necessarily "shave off" anything. Since a fireball expands with negligable force, it couldn't blow the doors off a hamster cage. It can melt metal and stone (I'd include earth/soil in that catagory), incinerate anything it deals enough damage to that would destroy it, burn and blister flesh, boil liquids, and little else. Being of instantaneous duration, it can't even ignite fires technically. Also, dealing enough damage to an object to destroy it does not simply make it vanish. A sundered sword can be reforged, a hinge that takes all the damage it can take will be a twisted, useless thing, but still there, etc. When a structure takes fatal damage it means that its structural integrity is gone. That could mean that something blew it apart, or that after taking so much damage it collapsed under its own weight.
badger3k 03-07-04, 09:56 PM	Personally, I wouldn't use it unless the attack was directed against the wall/floor/whatever. Mainly for reasons of speed - if you want to calculate how much damage a wall takes when a fireball explodes nearby, you can. For me, its enough to say that the furnishings are on fire and the wall is scorched. Now if the spell is specifically targeted to the wall, to breach it, then I'd determine the damage normally. Then there is a game-reason for it. Unless you want to have a lot of combats where the players have walls fall over, the floor drops away (well, really, the spell would either melt the dirt (?) or cause it to splatter around like a bomb explosion). I don't think the heat is enough to incinerate dirt to ashes, then take care of them too, not if there is anybody who is alive inside it. The other option is only use such things when it's dramatic - the floor is wooden, and over a long, long fall, or they need to attack over the wooden bridge (or stone even), and it could be dramatic to have the bridge damaged. Or else they use fireball and cone of cold in an area in rapid sequence, where the heat and cold can cause stone to shatter. Unless that was towards the wall, though, I'd probably just say that splinters of rock fly off the wall and leave it at that.
Loren Pechtel 03-07-04, 11:34 PM	I don't think a fireball would do anything more than cosmetic damage to earth or stone. I don't think it would transfer enough heat to melt enough material to actually cause it to flow away. The surface would be somewhat melted, images would be burned off etc, but I think you could throw them every day for a century without seriously eroding the walls. On the other hand, try throwing them around in a wooden city and you'll certainly see some effects!