How much can you melt with fireball

[Umbran]

Presuming the average of 3.5 points per dice, and a 10 dice fireball, you'll melt a bit less than 12 inches away from each exposed face.

Well, maybe.

What actually happens is you "destroy" a bit less than 12 inches from each exposed face. Melting is one interpretation. But so is shattering so it falls away from the walls (you can claim thermal stress) without actually melting it.

 

[Celebrim]

Energy attacks already do half damage to objects, by default, and Acid ignores hardness.

My focus is more on getting the physical interaction right, though acid's hardness bypassing mechanic was taken account in the discussion.

Unless alloyed specifically to be a weapons grade material, copper would be softer, not harder.

Copper is harder than silver. More importantly, it pretty much across the board has higher shear strength and resistance to deformation, and not by a little but by a lot (50% or more higher). I have no idea what 'alchemical silver' is so I would not use it as a reference point. I think the more appropriate reference point is iron. Copper has very different properties than iron, but overall I think 75% of the hardness and 2/3rds the hit points is reasonable. I don't think it is reasonable to classify iron and steel as the same material, but that's a different problem.

Brass refers to too wide a range of materials to say anything definitive about it. Some of them are softer than copper, and some of them much harder.

Bronze varies from about the strength of copper to roughly the strength of a steel depending on the quality and exact alloy.

Wood, in D&D, is all lumped into one standard, ignoring the softness of pine (or the extreme softness of balsa) compared to hardwoods like oak. Ash and hickory are both good for tool or weapon hafts, being hard, springy and resilient, while other,harder woods like walnut tend to be more brittle. I think they were considering structural grade wood, like oak, for the most part.

Agreed, though again, wood is a material that gains a lot of hardness with thickness. During the great age of sail, they'd have overlapping oak planks up to 24" thick, and would bounce shot from 12lb smoothbore cannons with no appreciable damage. That suggests a hardness much higher than 8 is possible.

As for the example of a spear v flesh being compared to a spear v wood or stone: Flesh doesn't have a Hardness in the game. Wood has a Hardness rating and Stone has a higher one. That more or less accounts for the difference you describe.

I think you misunderstand what I'm saying. Both a spear and a battle axe do base 1d8 damage. Each is equally effective at damaging soft tissue. In terms of game mechanics, each is equally effective against wood as well. But as a practical matter in the real world only the battle axe is going to effectively deal damage to wood because the mechanisms involved in dealing the damage are very different. Soft tissue is very vulnerable to piercing damage, but wood is very resistant to it. A spear, which relies on tissues inability to resist being punctured, doesn't have to deal a heavy blow, so is fairly terrible for chopping on wood regardless of how effective it is as a weapon against a person. An axe on the other hand deals the same sort of blow that is necessary to split the grain of wood and sever and splinter it. If your goal is high verisimilitude in the interaction with objects, hardness alone does not account for this difference.

In the real world, blades get dull pounding against armor, shields or other weapons used to block or parry. D&D makes no provision for things like that. The complexity of weapon degradation would be an insane addition to play.

It is, but only for cases where you are using the tool for its intended purpose. I would for example ignore degradation of an axe being used to chop wood, because the tool is designed to do that. If you took a spear or a sword and tried to chop wood, then I tend to handle that by apply the damage you inflict to the tool as well. If this damage exceeds the hardness of the tool, then you inflict damage on the tool as well. That isn't particularly hard to keep track of, and it doesn't come up often because it tends to cause players to simply not try to damage an object with an inappropriate tool. No more chopping through 10' of stone with your basic longsword, which is perfectly feasible in the RAW. By my rules, to do damage to the stone at all, you'd have to inflict so much damage that you'd be guaranteed to also damage your sword. Now of course, you could have a +5 adamantium sword and maybe that stone wall doesn't stand a chance, but now you are superhero probably, so chopping holes in stone is just something you can do.

 

[Greenfield]

My focus is more on getting the physical interaction right, though acid's hardness bypassing mechanic was taken account in the discussion.

Copper is harder than silver. More importantly, it pretty much across the board has higher shear strength and resistance to deformation, and not by a little but by a lot (50% or more higher). I have no idea what 'alchemical silver' is so I would not use it as a reference point. I think the more appropriate reference point is iron. Copper has very different properties than iron, but overall I think 75% of the hardness and 2/3rds the hit points is reasonable. I don't think it is reasonable to classify iron and steel as the same material, but that's a different problem.

I use Alchemical Silver as a reference point simply because the book does. It's described in the DMG as the silver alloy used to make "silver" weapons. That is, it's hard enough to hold an edge and take a hit in combat.

That alone makes it harder than even the cupranickel alloys used in coins, and much harder than straight copper.

Brass refers to too wide a range of materials to say anything definitive about it. Some of them are softer than copper, and some of them much harder.

Bronze varies from about the strength of copper to roughly the strength of a steel depending on the quality and exact alloy.

Agreed, though one could presume that the Bronze used to make the classic Gladius (Roman short sword) would be an alloy hard enough to make a useful blade.

Modern Bronze alloys approach the strength and resiliency of some steel alloys, particularly when you add phosphorus (Phosphorus does for Bronze what Carbon does for iron, making it possible to harden via heat treating.) This is, however a strictly modern adaptation.

I think you misunderstand what I'm saying. Both a spear and a battle axe do base 1d8 damage. Each is equally effective at damaging soft tissue. In terms of game mechanics, each is equally effective against wood as well. But as a practical matter in the real world only the battle axe is going to effectively deal damage to wood because the mechanisms involved in dealing the damage are very different. Soft tissue is very vulnerable to piercing damage, but wood is very resistant to it. A spear, which relies on tissues inability to resist being punctured, doesn't have to deal a heavy blow, so is fairly terrible for chopping on wood regardless of how effective it is as a weapon against a person. An axe on the other hand deals the same sort of blow that is necessary to split the grain of wood and sever and splinter it. If your goal is high verisimilitude in the interaction with objects, hardness alone does not account for this difference.

Not exactly a fair comparison. The axe was originally designed to cut wood, and the spear to penetrate flesh. A solid spear or arrow strike may well penetrate deeper into the wood that the axe blade, but the axe cuts a broader swath of damage.

Should we make damage adjustments in game for piercing v bludgeoning v slashing damage, based on the material? We could. I don't think, personally, that the added complexity would be worth it.

In game design, you are looking at three goals: Realism, playability, and believability. A combination of either realism or believability with playability is good, but playability must always be present. There are realistic results that often run counter to what our gut reaction says should happen, but rules that adopt either or both of these, but aren't practically playable, are a failure.

It is, but only for cases where you are using the tool for its intended purpose. I would for example ignore degradation of an axe being used to chop wood, because the tool is designed to do that. If you took a spear or a sword and tried to chop wood, then I tend to handle that by apply the damage you inflict to the tool as well. If this damage exceeds the hardness of the tool, then you inflict damage on the tool as well. That isn't particularly hard to keep track of, and it doesn't come up often because it tends to cause players to simply not try to damage an object with an inappropriate tool. No more chopping through 10' of stone with your basic longsword, which is perfectly feasible in the RAW. By my rules, to do damage to the stone at all, you'd have to inflict so much damage that you'd be guaranteed to also damage your sword. Now of course, you could have a +5 adamantium sword and maybe that stone wall doesn't stand a chance, but now you are superhero probably, so chopping holes in stone is just something you can do.

I can hack firewood with a sword and dull the edge no more than I would dull the edge of an axe. I can chip away at firewood by digging in it with a spear point the same way.

The axe, being designed for the job, will cut the wood faster than the sword. The spear, not being designed to "cut" at all, is going to come in a distant third.

But steel blades have a greater hardness than wood. If I were to integrate weapon degradation rules, I'd have it based on relative hardness. The softer material, based on that hardness rating, would suffer "degradation".

Your comparison of the axe to the sword is interesting though. Perhaps there needs to change of phraseology, where we change the "Slashing" designation to "Cutting", and then subdivide that into "Slashing" and "Chopping", when it comes to relative effectiveness against various materials.

As for the +5 Adamantine longsword v the stone wall: Under current rules, that blade is just short of a lightsabre against that wall. It ignores the stone hardness completely, and just carves at it as if it were thick clay.

 

[Morlock]

The fireball description mentions that it can melt things such as copper. Of the materials listed copper has the highest latent heat of fusion and melting point. The question I'm trying to answer is, how much mass can the fireball effect? Could a fireball melt a 20ft hemisphere of copper? (assuming the passage to the center has negligible effect on the mass) Something smaller like a copper piece?

My end goal, after determining how much heat is generated by a fireball, is to see how much ice you could melt with a fireball.

I have no idea why I'm advising a guy who uses terms like "latent heat of fusion" on this subject. That said, I was going to say pretty much what Koloth said.

I'd add that a good place to investigate would be the effects of bombs. I get the impression that a typical bomb partially melts stuff like plastics, but doesn't really do that much heat damage. Though you could make the argument that a fireball is more like an incendiary bomb, like napalm, or white phosphorous, which, I presume, does more fire damage than a typical bomb does.

 

[Celebrim]

I use Alchemical Silver as a reference point simply because the book does. It's described in the DMG as the silver alloy used to make "silver" weapons. That is, it's hard enough to hold an edge and take a hit in combat.

Taking an edge and hardness aren't completely related. Titanium for example doesn't take an edge easily nor retain an edge well despite being fairly hard.

Agreed, though one could presume that the Bronze used to make the classic Gladius (Roman short sword) would be an alloy hard enough to make a useful blade.

Presumably, yes. During the iron age, the finest swords were still made of bronze. Iron replaced bronze in weapons mostly because of issues of cost and quality control, and steel didn't completely replace it until sometime in the dark ages. I wouldn't be entirely too sure that bronze allies to modern standards were unknown, as 'evolved' technology can achieve pretty remarkable results with only limited understanding of the whys and hows. Individual examples of swords with ideal ratios of copper, tin, and phosophor and relatively free of impurities are known, particularly among Egyptian bronze.

Not exactly a fair comparison. The axe was originally designed to cut wood, and the spear to penetrate flesh. A solid spear or arrow strike may well penetrate deeper into the wood that the axe blade, but the axe cuts a broader swath of damage.

I think that's pretty much exactly my point and why it is a fair comparison.

I can hack firewood with a sword and dull the edge no more than I would dull the edge of an axe. I can chip away at firewood by digging in it with a spear point the same way.

The axe, being designed for the job, will cut the wood faster than the sword. The spear, not being designed to "cut" at all, is going to come in a distant third.

In D&D, damage => time. The more damage the object does to the material, the faster that it whittles it away. Your own analysis establishes that we know axes do more damage to wood than swords, and swords more than spears.

But steel blades have a greater hardness than wood. If I were to integrate weapon degradation rules, I'd have it based on relative hardness. The softer material, based on that hardness rating, would suffer "degradation".

Effectively, this his how it works out. If I attack a hardness 8 object with a hardness 12 object, I can do up to 4 damage to the object I'm whittling on while doing none to the implement I'm wielding. Conversely, if I try to attack a hardness 12 object with a hardness 8 object, I'll soon damage eventually break the softer object.

 

[bone_naga]

I'd add that a good place to investigate would be the effects of bombs. I get the impression that a typical bomb partially melts stuff like plastics, but doesn't really do that much heat damage. Though you could make the argument that a fireball is more like an incendiary bomb, like napalm, or white phosphorous, which, I presume, does more fire damage than a typical bomb does.

That is correct. Even with a plastic-cased anti-tank landmine containing anywhere from 10-20 lbs of high explosives, you can find pieces of the plastic case after the fact (assuming you're willing to spend the time and effort to search and dig for them). They'll be melted, but still somewhat recognizable if you were familiar with the original shape. And that's something that was physically touching the explosives. Plastic and even foam have survived pretty large explosions with just a little bit of separation from the explosive charge. Of course, in these cases the heat is generated in an instant, plus nearby objects are being pushed away by the blast wave.

For an incendiary bomb, you get a better heat effect because the compound is still burning following its employment, so it would be better at burning things. However, they don't typically burn through metal. Even thermite is much less effective against thick metal than most people expect.

I think a fireball would be weaker than an explosion. It would basically be a deflagration, a rapid but subsonic burn. So less energy than a detonation of high explosives, but still almost instantaneous, so you wouldn't get the continued burning like napalm or white phosphorus could cause. So kind of like firing a bullet, where gunpowder rapidly burns inside the cartridge case, which doesn't melt even the small amount of copper jacketing a typical bullet. Naturally, a fireball could ignite flammable materials nearby, just like an explosion, but that would just be a normal fire and would be unlikely to melt metal.

In the end, it does whatever you want it to do. After all, it's magic. It's already breaking the rules of the real world. What's important is that it is internally-consistent. In that respect, I would be careful about giving its heat overly-powerful effects since that will almost certainly be exploited again down the road.

The 2nd Ed Player's Option: Spells & Magic had an entire section about the additional effects generated by spells like fireballs. IIRC, it generally boiled down to igniting flammable materials and consuming oxygen in enclosed environments.

 

[Greenfield]

Unlike a bomb, Fireball exerts minimal explosive pressure. Think of the circus performer who sips flamable liquid, then sprays it through a small torch: They get a cloud of fire, but it's all heat, no "boom". It won't send pieces of anything anywhere.

Many super-hero games talk about "special effect", meaning "what does this power look like". So an "Energy Blast" can be described as looking like fire, or lightning, lasers or simply a blast of glowing, undefined "energy".

I see the "Melts soft metals" description in that light. It's simply defining the form the damage from the Fireball takes on that class of materials: If it has a "low" melting point, any damage it takes is in the form of melting.

Harder materials, like stone, might show damage as thermal fracturing. (Anyone who ever held a welding torch against concrete knows what I'm talking about (and no, don't try that at home.))

Other materials might char. Steel weapons could take damage by softening, as "having the temper of the steel ruined", or oxidized into rust.

These are all visuals, different ways of describing the damage items and materials take so as to be constant with a flash of magically hot flame.

At least, that's what seems like the simplest explanation that falls in line with the RAW. YMMV, of course.

 

[S'mon]

I might have a fireball melt the outer surface of coins, so in a big pile the outer coins might fuse together. I generally wouldn't have iron be seriously affected.
On ice over water, a fireball might weaken thin ice enough for characters standing on the ice to fall through. It won't vapourise large quantities of ice, but a snowball certainly would be vapourised.
The biggest effect of Fireball is vs ships - tar caulking, cloth sails, rope rigging, wooden hull - the hull per se probably won't ignite directly, but all the other stuff will, causing a fire that will likely burn to the waterline. A single 40' diameter fireball can take out a small ship, 2 fireballs can take out most ships.

 

[Celebrim]

A single 40' diameter fireball can take out a small ship, 2 fireballs can take out most ships.

The recognition that this was true prompted me to reconsider how ubiquitous low level magic was. Obviously, if a fireball can take out a ship, either people don't build warships or else they build warships to counter that - which requires those mages that can cast fireball to be continually engaged in the industry of proofing things against fireball and the like.

Quite the economic scheme if you think about it.

 

[Grogg of the North]

I might have a fireball melt the outer surface of coins, so in a big pile the outer coins might fuse together. I generally wouldn't have iron be seriously affected.
On ice over water, a fireball might weaken thin ice enough for characters standing on the ice to fall through. It won't vapourise large quantities of ice, but a snowball certainly would be vapourised.
The biggest effect of Fireball is vs ships - tar caulking, cloth sails, rope rigging, wooden hull - the hull per se probably won't ignite directly, but all the other stuff will, causing a fire that will likely burn to the waterline. A single 40' diameter fireball can take out a small ship, 2 fireballs can take out most ships.

In the Golden Age of Sail, many nations actually lined their ships with copper. This reduced plant growth on the hulls and protected the wood from worms. I recall reading that it was so effective that the French ships were able to outmaneuver the British navy and choose when and where to engage. Whether that would protect a ship against a fireball, I don't know.

The thing that would protect a ship versus fireball is gold. Ships are expensive and require a long time to build. If you have adventurers running around on the high seas, I bet that the local governments are going to offer a bounty on any captured ships they bring back with them. And if you sink that ship to the bottom of the ocean all your loot goes down with it.

Hmm ... I think I may have just hijacked my own thread....