A Sword Without a Hilt: A Song of Ice and Fire/D&D 3.5 Crossover
- Thread starter DragonParadox
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- a song of ice and fire a sword without a hilt d&d 3.5 dungeons & dragons 100% high octane dragon fuel ave corvidae battle action dragon diplomacy best sister bureaucromancy delicious soul-stuff dragon dreams come true dragon ta'veren greatest uncle hubris is a coward's word in defiance of gods and men mammon's folly mutually assured mage's disjunction qm murderhobo top tier coatl
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Listen up you primitive screw heads! This is my
Magitek Railgun
Warning: Contains Math, Mad Science and Hubris, Keep Away From Children Under Level 3
1. Physics
First thing first, we need to find out how much 1 point of lightning damage is in real world units. To find this out, we use 5 feet long iron pole with a diameter of 1 inch.
π * ( 0.5 in )² = 0.79 in²
0.79 in² * 5 ft = 776.7468 cm³
776.7468 cm³ * 7.847 g / cm³ (densitiy of iron) = 6.1161 kg
According to this, it will need roughly 550 kw/h of electricity to melt a ton of raw iron.
550 kw/h * 0.0061161 = 3.3639 kw/h
This would completely liquefy our iron pole.
Said pole has Hardness 10 and 30 Hitpoints, for a total of 40 electricity damage to completely destroy it. D&D says that electricity and fire usually do half damage against objects, but halving electricity damage to iron seems just as sane as halving that of fire against wood.
Let's now eliminate the time dimension by converting to MegaJoule and get the final power.
1 kw/h = 3.6 MJ
3.3639 kw/h * 3.6 = 12.11 MJ
12.11 MJ / 40 ED = 302.75 kJ / ED
Since this damage is done entirely by Joule Heating, we can now calculate the actual current.
Energy = Volt * Ampere = Volt² / Resistance
Resistance = Resistivity * Length / Crosssection
Resistivity of iron = 9.71×10−8
Therefore:
9.71×10−8 * 1.524 m (length in a sane unit) / 5.096764x10-4 m² = 2.90342x10-4 Ohm
SqrRoot( 302.75 kJ * 2.90342x10-4 Ohm ) = 296.4811 V
302.75 kJ / 296.4811 V = 1.0211 A
Given that the energy scales linearly with every ED and assuming that the voltage of a electricity attack remains static, we can assume that Ampere grow linearly with ED, giving us:
A(x) = A(1) * x
Now let's calculate what we get for our buck.
Normally a railgun has the problem with the very low inductivity of the the rails requiring tremendous amounts of energy to launch a projectile. This is a simple result of no coiled wire being able to withstand the forces of the launch. The projectile would destroy the rail before it has even reached the end of the barrel.
However, this isn't Real Life, but D&D and we are cheating bastards.
By making the rails into Adamantine coils which are fixed into place with a Wall of Force, we can get a optimized setup that can easily withstand the forces of firing. While regular Wall of Force seems not up to the task, Riverine is proof that the effect can be used to make nigh indestructible materials. Pricey, but worth it.
We thus use Adamantine wire around a iron core and encase everything in a Wall of Force effect, except for thin Adamantine contacts in the barrel, which allow the projectile to close the circuit. To make the whole thing even sturdier, we liberally apply Harden to the setup.
The inductivity of a coil is given by:
L = µ0 * µ * Coils² * Crosssection / Length
We assume an average of 5000 coils per meter of the coil, a crossection of 25 cm² and a length of one meter. Due to the length of the coil changing as the projectile moves through it, the rail isn't uniform if we want a constant inductivity, which is preferable for a uniform acceleration.
L = (4πx10-7) * 5000 * 5000² * 0.0025 m² / 1m
L = 392.6991 H
I won't go into too much detail of railgun design, since my browser history is already questionable enough, but Wikipedia supplies a simple formula:
F = L * I² / 2
Which gives us:
(1.0211 A)^2 * ED^2 * 392.6991 H / 2 = F
F = ED² * 204.7229 N / ED²
The final energy of the projectile is thus given by:
ED² * 204.7229 N / ED² * Barrel Length = x Joule
2. Costs
First, the rails. We assume that the weight of the coils per cm³ is the same as iron.
π * ( 2.5 cm )² = 19.634954 cm²
19.634954 cm² * 100 cm = 1963.4954 cm³
1963.4954 cm³ * 7.847 g / cm³ (densitiy of iron) = 15.407,5485 kg = ~34 pounds
Since the most weight comes actually from the iron core, not the Adamantine-Riverine bastardization around it, we will assume that we only have to pay for 20 pounds of material, the rest being dirt cheap iron. A chain shirt weighs 40 pounds, so we will assume that the material value of it will cover the cost for two parallel rails per meter of their length.
16,000 GP (Riverine) + 10,000 GP (Adamantine) = 26,000 GP per meter = 5,200 IM per meter
Turns out WMDs don't come cheap and we haven't even started on spells.
We can safely ignore Harden, since that is only cast at the rails once and doesn't need to be enchanted into the gun itself. However, we do need spellwork to make sure the gun doesn't break down after a few shots due to overheating or wear. The latter is covered for the rails themselves, but unless we want to shell out even more money to build the whole carriage out of hideously expensive materials, it's better to add Make Whole.
Make Whole: 1800 GP (Command Activated) * 2 (Spell Level) * 3 (Caster Level) = 10,800 GP = 1,080 IM -> 810 IM (Lya Price)
For overheating, we will use Chill Metal, which explicitly is capable of negating heat damage.
Chill Metal: 1800 GP (Command Activated) * 2 (Spell Level) * 3 (Caster Level) = 10,800 GP = 1,080 IM -> 810 IM (Lya Price)
Finally, we need energy. Ironically enough, we get the best ratio of ED / GP by the lowly Shocking Grasp. To get half-way regular values, we will assume a basic "Power Unit" of 4d6 ED, which we average out to 14 ED. Each unit costs:
Power Unit / Shocking Grasp: 1800 GP (Command Activated) * 1 (Spell Level) * 4 (Caster Level) = 7,200 GP = 720 IM -> 540 IM (Lya Price)
Which gives us a final table of:
3. Final Design
Now we plug everything together. For the final calculation of total kinetic energy of the projectile, we will assume a energy loss of 25% during acceleration. We will use a 2m long rail and 20 PU = 280 ED as the power source, while firing a 20kg projectile.
Thus we get:
(420 ED)² * 204.7229 N / ED² * 2m * 0.75 (Energy Loss) =24.0754 MJ
Punching this into the kinetic energy formula, we get our velocity:
SqrRoot( 24.0754 MJ * 2 / 20kg) = 1551.63 m/s
D&D is slightly crazy with falling object damage. A 20kg = ~44 lb projectile would need to travel 40ft per round to do 1d6 of damage. This is pretty bogus, but let's roll with it. We will assume that the projectile has lost 50% of its speed by the time it hits the target.
50 ft / 6s = 2.032 m/s
1551.63 m/s * 0.5 (Speed Loss) / 2.032 m/s = ~ 382d6 of damage -> average of 1337 HP on a direct hit
Total Cost:
Materials: 10,400 IM
Crafting Materials: 12,420 IM
Time in Days: 62.1
The face of Tywin Lannister when we shell Casterly Rock into rubble: Priceless
4. Ammunition
Due to the forces involved, the projectile has to withstand quite some punishment. Regular steel shells will melt after a while, making them unsuitable for long range fire. So these shells are only really useful for close engagements.
However, there are other options:
Adamantine Tipped(AT) - Directly mitigates the problems by making the tip more sturdy, but it will melt all the same given a few kilometers of flight and once the Adamantine is gone, the steel will evaporate immediately.
Adamantine Mantled(AM) - Unlike the version with just a tip from Adamantine, this one will last a lot longer, but obviously require more Adamantine.
Adamantine Tipped Flat Top Shell (AT-FT) - By making the tip of the shell into a flat surface, we are actually improving the air resistance of the shell. The tip will take quite a bit of punishment, but push the air out of the way and form a vacuum bubble around the shell, which massively cuts down on drag and friction. Also useful for underwater use.
Riverine Tipped Flat Top Shell (RT-FT) - Basically the same as AT-FT, but since Riverine flat out no-sells damage, the melting problem disappears entirely. Obviously a pricey option.
Steel Cannister (SC) - The shell is designed to break apart from drag shortly after launch, releasing shrapnel. Nice to clean up large groups near the gun.
Adamantine Cannister (AC) - Basically the same as above, but by using Adamantine instead of steel, we can extend the distance the shell travels before breaking apart, thus allowing shrapnel bombardments of long range targets.
Before somebody asks, no, we can't fire Wildfyre or other chemically non-inert stuff with this. It would go up in the barrel once the electricity is applied.
However, since the thing is just accelerating metal really, really fast, most of the common defenses against long range strikes become ineffective against it. No SR, no wards, no AM shielding, no nothing.
It's just the wrath of an angry dragon, delivered as a half molten chunk of hyper-sonic death.
@DragonParadox, too far?
Magitek Railgun
Warning: Contains Math, Mad Science and Hubris, Keep Away From Children Under Level 3
1. Physics
First thing first, we need to find out how much 1 point of lightning damage is in real world units. To find this out, we use 5 feet long iron pole with a diameter of 1 inch.
π * ( 0.5 in )² = 0.79 in²
0.79 in² * 5 ft = 776.7468 cm³
776.7468 cm³ * 7.847 g / cm³ (densitiy of iron) = 6.1161 kg
According to this, it will need roughly 550 kw/h of electricity to melt a ton of raw iron.
550 kw/h * 0.0061161 = 3.3639 kw/h
This would completely liquefy our iron pole.
Said pole has Hardness 10 and 30 Hitpoints, for a total of 40 electricity damage to completely destroy it. D&D says that electricity and fire usually do half damage against objects, but halving electricity damage to iron seems just as sane as halving that of fire against wood.
Let's now eliminate the time dimension by converting to MegaJoule and get the final power.
1 kw/h = 3.6 MJ
3.3639 kw/h * 3.6 = 12.11 MJ
12.11 MJ / 40 ED = 302.75 kJ / ED
Since this damage is done entirely by Joule Heating, we can now calculate the actual current.
Energy = Volt * Ampere = Volt² / Resistance
Resistance = Resistivity * Length / Crosssection
Resistivity of iron = 9.71×10−8
Therefore:
9.71×10−8 * 1.524 m (length in a sane unit) / 5.096764x10-4 m² = 2.90342x10-4 Ohm
SqrRoot( 302.75 kJ * 2.90342x10-4 Ohm ) = 296.4811 V
302.75 kJ / 296.4811 V = 1.0211 A
Given that the energy scales linearly with every ED and assuming that the voltage of a electricity attack remains static, we can assume that Ampere grow linearly with ED, giving us:
A(x) = A(1) * x
Now let's calculate what we get for our buck.
Normally a railgun has the problem with the very low inductivity of the the rails requiring tremendous amounts of energy to launch a projectile. This is a simple result of no coiled wire being able to withstand the forces of the launch. The projectile would destroy the rail before it has even reached the end of the barrel.
However, this isn't Real Life, but D&D and we are cheating bastards.
By making the rails into Adamantine coils which are fixed into place with a Wall of Force, we can get a optimized setup that can easily withstand the forces of firing. While regular Wall of Force seems not up to the task, Riverine is proof that the effect can be used to make nigh indestructible materials. Pricey, but worth it.
We thus use Adamantine wire around a iron core and encase everything in a Wall of Force effect, except for thin Adamantine contacts in the barrel, which allow the projectile to close the circuit. To make the whole thing even sturdier, we liberally apply Harden to the setup.
The inductivity of a coil is given by:
L = µ0 * µ * Coils² * Crosssection / Length
We assume an average of 5000 coils per meter of the coil, a crossection of 25 cm² and a length of one meter. Due to the length of the coil changing as the projectile moves through it, the rail isn't uniform if we want a constant inductivity, which is preferable for a uniform acceleration.
L = (4πx10-7) * 5000 * 5000² * 0.0025 m² / 1m
L = 392.6991 H
I won't go into too much detail of railgun design, since my browser history is already questionable enough, but Wikipedia supplies a simple formula:
F = L * I² / 2
Which gives us:
(1.0211 A)^2 * ED^2 * 392.6991 H / 2 = F
F = ED² * 204.7229 N / ED²
The final energy of the projectile is thus given by:
ED² * 204.7229 N / ED² * Barrel Length = x Joule
2. Costs
First, the rails. We assume that the weight of the coils per cm³ is the same as iron.
π * ( 2.5 cm )² = 19.634954 cm²
19.634954 cm² * 100 cm = 1963.4954 cm³
1963.4954 cm³ * 7.847 g / cm³ (densitiy of iron) = 15.407,5485 kg = ~34 pounds
Since the most weight comes actually from the iron core, not the Adamantine-Riverine bastardization around it, we will assume that we only have to pay for 20 pounds of material, the rest being dirt cheap iron. A chain shirt weighs 40 pounds, so we will assume that the material value of it will cover the cost for two parallel rails per meter of their length.
16,000 GP (Riverine) + 10,000 GP (Adamantine) = 26,000 GP per meter = 5,200 IM per meter
Turns out WMDs don't come cheap and we haven't even started on spells.
We can safely ignore Harden, since that is only cast at the rails once and doesn't need to be enchanted into the gun itself. However, we do need spellwork to make sure the gun doesn't break down after a few shots due to overheating or wear. The latter is covered for the rails themselves, but unless we want to shell out even more money to build the whole carriage out of hideously expensive materials, it's better to add Make Whole.
Make Whole: 1800 GP (Command Activated) * 2 (Spell Level) * 3 (Caster Level) = 10,800 GP = 1,080 IM -> 810 IM (Lya Price)
For overheating, we will use Chill Metal, which explicitly is capable of negating heat damage.
Chill Metal: 1800 GP (Command Activated) * 2 (Spell Level) * 3 (Caster Level) = 10,800 GP = 1,080 IM -> 810 IM (Lya Price)
Finally, we need energy. Ironically enough, we get the best ratio of ED / GP by the lowly Shocking Grasp. To get half-way regular values, we will assume a basic "Power Unit" of 4d6 ED, which we average out to 14 ED. Each unit costs:
Power Unit / Shocking Grasp: 1800 GP (Command Activated) * 1 (Spell Level) * 4 (Caster Level) = 7,200 GP = 720 IM -> 540 IM (Lya Price)
Which gives us a final table of:
| Part | GP | IM | Lya |
| Rails (per meter) | 26,000 GP | 5,200 IM | 5,200 IM |
| Make Whole | 10,800 GP | 1,080 IM | 810 IM |
| Chill Metal | 10,800 GP | 1,080 IM | 810 IM |
| Power Unit (per 14 ED) | 7,200 GP | 720 IM | 540 IM |
Now we plug everything together. For the final calculation of total kinetic energy of the projectile, we will assume a energy loss of 25% during acceleration. We will use a 2m long rail and 20 PU = 280 ED as the power source, while firing a 20kg projectile.
Thus we get:
(420 ED)² * 204.7229 N / ED² * 2m * 0.75 (Energy Loss) =24.0754 MJ
Punching this into the kinetic energy formula, we get our velocity:
SqrRoot( 24.0754 MJ * 2 / 20kg) = 1551.63 m/s
D&D is slightly crazy with falling object damage. A 20kg = ~44 lb projectile would need to travel 40ft per round to do 1d6 of damage. This is pretty bogus, but let's roll with it. We will assume that the projectile has lost 50% of its speed by the time it hits the target.
50 ft / 6s = 2.032 m/s
1551.63 m/s * 0.5 (Speed Loss) / 2.032 m/s = ~ 382d6 of damage -> average of 1337 HP on a direct hit
Total Cost:
Materials: 10,400 IM
Crafting Materials: 12,420 IM
Time in Days: 62.1
The face of Tywin Lannister when we shell Casterly Rock into rubble: Priceless
4. Ammunition
Due to the forces involved, the projectile has to withstand quite some punishment. Regular steel shells will melt after a while, making them unsuitable for long range fire. So these shells are only really useful for close engagements.
However, there are other options:
Adamantine Tipped(AT) - Directly mitigates the problems by making the tip more sturdy, but it will melt all the same given a few kilometers of flight and once the Adamantine is gone, the steel will evaporate immediately.
Adamantine Mantled(AM) - Unlike the version with just a tip from Adamantine, this one will last a lot longer, but obviously require more Adamantine.
Adamantine Tipped Flat Top Shell (AT-FT) - By making the tip of the shell into a flat surface, we are actually improving the air resistance of the shell. The tip will take quite a bit of punishment, but push the air out of the way and form a vacuum bubble around the shell, which massively cuts down on drag and friction. Also useful for underwater use.
Riverine Tipped Flat Top Shell (RT-FT) - Basically the same as AT-FT, but since Riverine flat out no-sells damage, the melting problem disappears entirely. Obviously a pricey option.
Steel Cannister (SC) - The shell is designed to break apart from drag shortly after launch, releasing shrapnel. Nice to clean up large groups near the gun.
Adamantine Cannister (AC) - Basically the same as above, but by using Adamantine instead of steel, we can extend the distance the shell travels before breaking apart, thus allowing shrapnel bombardments of long range targets.
Before somebody asks, no, we can't fire Wildfyre or other chemically non-inert stuff with this. It would go up in the barrel once the electricity is applied.
However, since the thing is just accelerating metal really, really fast, most of the common defenses against long range strikes become ineffective against it. No SR, no wards, no AM shielding, no nothing.
It's just the wrath of an angry dragon, delivered as a half molten chunk of hyper-sonic death.
@DragonParadox, too far?
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- Location
- United States
Too much math, head exploded
- Location
- being near locations is my passion.
Need either Hallow or Consecrate. Not a huge deal, but moderately inconvenient.
Consecrate :: d20srd.org
Second level spell, lya has it.
@DragonParadox @all Can we have 2-5 scrolls of this made by lya for all of our divine casters and Maelor and Glyra?
Not at all. It's enormously powerful but also hideously costly. Sounds about right for a major artifact equivalent, with the power of: if it hits you you are dead.
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- Location
- Mexico
@DragonParadox the others Alyneah was talking about were the Djinn and possibly her family after she was decursed? or did her oath prevent her from telling us even after we killed the dark djinn?
Her oath did not have such clauses in it, she could not tell you anything about the situation until you confirmed it by some other source, like Embar telling you who she is. In that situation she was allowed use her judgement.
- Location
- Germany
- Pronouns
- He/Him
Actually, for Iron it makes a lot of sense since it's a quite good conductor.
And now you have to find a reason why the Wall of Force doesn't stop the magnetic field.
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Since the tally looks contested I'll to an interlude next so give you guys time o discuss the matter properly.
- Location
- Germany
Which is my point. Electricity would have a much harder time affecting wood or stone then iron, since it wouldn't be able to really penetrate the material and just cause superficial damage.
egoo
Totally Not Creating Problems Where None Existed
- Location
- Russia
@Azel, you have won everything and everywhere forever.
*Zap*
*Whoooosh*
Well, now we need another dragon-god to take her place. Who that might be...
In all seriousness though, great job, I'm genuinely very much fucking impressed.
Even though I don't understand like 80% of math.
So, shall we start building it right away so we'll get it ready in time to shell the fuck out of Elder Brain?
Oh, hi Tiamath.
*Zap*
*Whoooosh*
Well, now we need another dragon-god to take her place. Who that might be...
In all seriousness though, great job, I'm genuinely very much fucking impressed.
Even though I don't understand like 80% of math.
So, shall we start building it right away so we'll get it ready in time to shell the fuck out of Elder Brain?
- Location
- United Kingdom
[X] Goldfish
Goldfish
Friendly Spider-Fish Abomination
- Location
- Formerly of the Far Realm
I can totally get behind this, but it probably isn't gonna happen.
Too far outside the conceivable mental and experiential paradigm of even Lya or the Bulbasaurs. She's more likely to puzzle out enough of the underpinnings of reality and the physical forces which govern it, then use that knowledge to invent a spell which creates short-lived micro-singularity.
EDIT: I stand corrected. DP approval given. The God Killer has the green light.
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- Location
- Germany
Technically it can't overcome DR/Epic, since it's firing only hunks of steel, so Tiamat should be safe. However, we can just load +6 RT-FT shells to fix that issue.
Mind you that the Doomblob in Lys has no DR/Epic. It would go down after two hits.
- Location
- being near locations is my passion.
So... how does Viserys think he can convince the Earth/Air genies to drop a few mindblanks and then get with the wish construction, 'cuz I imagine that they would want some of these for themselves.
.With mind blank imbued into the schematics and such.
License the design to one of the wealthiest polities in the planes. A lawful wealthy plane.
I think that might be worth their time and wishes to make
.And ask can we test it out on some purpose built adamantium walls (the adamantium can always be fabricated back into shape after).
A force wall will no-sell it.
Would it be possible to get a disintegration on-hit effect on the riverine tipped shells so as to break through force-walls, or would a cheaper, much much smaller launcher for tiny darts with on-hit disintegrate be worth developing?
Hmm, prismatic walls might be trickier - a series of lighter darts launched in order with the appropriate on-hit spell added, then in the same round, fire the railgun.
Chronomancy to recast defences after they are brought down, but in the microsecond before the railgun is fired would probably the only way to resist such a thing imo. Or divine action, but God's are bs anyway.
Or, thinking on it, layered force/prismatic walls.
Sorry, I've gotten excited about this, so I immediately start thinking of how to stop it, and then how to get around said stopping
But i do think mindblank scale antidivination effects imbued into the plans and each railgun are very much on the cards.
- Location
- being near locations is my passion.
Walls of force does not stop light, "creates an invisible wall of pure force" - so maybe it is also invisible to magnetic fields?
Then again, if someone cast magnetic attraction spell, I'd expect the wall of force to no-sell any effects on the opposite side.
Speciality wall of force, permeable by magnetic fields?
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Starmantle makes you immune to non-magical damage ...
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- Germany
I honestly wouldn't care if it is never used. It was a fun mental exercise to design this monster.
That being said, if anyone of you needs a Artifact of Doom for a D&D campaign, feel free.
Goldfish
Friendly Spider-Fish Abomination
- Location
- Formerly of the Far Realm
DR/Epic would only block the first few points of OMFFUCKYOUTODEATH aimed at Tiamat.
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- Germany
- Pronouns
- He/Him
Would the wall be visible if it stopped light?
- Location
- Germany
Then we use +1 shells. The only things truly capable of no-selling it are Resilient Sphere, Wings of Cover and Wall of Force.
Though we might able to make single-use shells that cast AMF on themselves after leaving the barrel. Hideously costly, but eh.
- Location
- being near locations is my passion.
Your question makes me feel that my comment was somehow unclear or confusing, but I cannot see how.
Visible means that it would either be translucent or opaque, stopping/reflecting some or all light. So... yeah.
Um, if this is not what you were asking, opps?