Is it too easy to cast powerful spells with RPM?

[qchap]

Thank you for all your advices!

[Varyon]

Originally Posted by ajardoor

Disabling the security measures on a nuclear warhead?

I don't know about the particular spell Chris is talking about, but I will note that, without a GM who's willing to Rule Zero his/her way out of it, Lesser Create Matter (6) + Duration, 10 minutes (1) + Subject Weight, 300 lb (3) will, for the low, low cost of 10 energy, create a mass of plutonium that will more-or-less immediately turn into a nuclear fireball (without proper shaping, it would be a rather dirty bomb, but all the excess plutonium will vanish in 10 minutes anyway). GM oversight is critical.

(Incidentally, if you want your players to be able to make various flavors of explosives, but feel - rightly - that this is too cheap, consider charging for potential energy)

[qchap]

Originally Posted by Varyon

I don't know about the particular spell Chris is talking about, but I will note that, without a GM who's willing to Rule Zero his/her way out of it, Lesser Create Matter (6) + Duration, 10 minutes (1) + Subject Weight, 300 lb (3) will, for the low, low cost of 10 energy, create a mass of plutonium that will more-or-less immediately turn into a nuclear fireball (without proper shaping, it would be a rather dirty bomb, but all the excess plutonium will vanish in 10 minutes anyway). GM oversight is critical.

(Incidentally, if you want your players to be able to make various flavors of explosives, but feel - rightly - that this is too cheap, consider charging for potential energy)

As I understand the system, this ritual is not correct. You should pay for explosive damage in case you want the plutonium to explode. If you dont - either GM should just say that the ritual is impossible (you are trying to create plutonium that would NOT explode) or, if he allows it, then the created plutonium just don't explode for some reason - it's magic.
Similar example is shown in How to be a GURPS GM: RPM. So, I think this is not a problem for GM, the system clearly solves it.

[Fred Brackin]

[QUOTE=Varyon;2414845, Lesser Create Matter (6) + Duration, 10 minutes (1) + Subject Weight, 300 lb (3) will, for the low, low cost of 10 energy, create a mass of plutonium that will more-or-less immediately turn into a nuclear fireball (without proper shaping, it would be a rather dirty bomb, but all the excess plutonium will vanish in 10 minutes anyway).[/QUOTE]

The fact that you're talking about 23x the amount of plutonium used at Nagasaki would make up for a lot but your main lack is probably the absence of a "tamper" to keep the critical mass from blowing itself apart too fast.

Note that to do this in default Magic is harder. It's Create Fuel/TL7 at 7 energy/lb. Just the 13 lbs for the same mass used at Nagasaki would cost 91 energy. Better put a Delay on that while you cast a big Teleport with the energy you saved out.

[Christopher R. Rice]

Originally Posted by ajardoor

Aye.
It's important for the GM to point out the issues surrounding RPM tools - availability, costs, other actors' interference, etc.

Indeed

Originally Posted by ajardoor

What was the spell? Starting a neighbourhood-wide fire? Creating a disease? Disabling the security measures on a nuclear warhead?

Essentially, a spell that used the Law of Contagion to destroy an entire Cabal. I eventually disallowed it because wow was that powerful only to reallow it using some rules I created to make the cost in line with the effect.

Originally Posted by qchap

As I understand the system, this ritual is not correct. You should pay for explosive damage in case you want the plutonium to explode. If you dont - either GM should just say that the ritual is impossible (you are trying to create plutonium that would NOT explode) or, if he allows it, then the created plutonium just don't explode for some reason - it's magic.
Similar example is shown in How to be a GURPS GM: RPM. So, I think this is not a problem for GM, the system clearly solves it.

This is correct. In RPM you get what you pay for. There is no such thing as a free lunch.

[Michael Thayne]

Originally Posted by Christopher R. Rice

Essentially, a spell that used the Law of Contagion to destroy an entire Cabal. I eventually disallowed it because wow was that powerful only to reallow it using some rules I created to make the cost in line with the effect.

How was it built? Something like Advantage, Affliction (this Affliction plus other bad stuff, Always On)?

[Christopher R. Rice]

Originally Posted by Michael Thayne

How was it built? Something like Advantage, Affliction (this Affliction plus other bad stuff, Always On)?

No. It was a RPM spell and built as a RPM spell. I'd have to dig it out but it was basically internal damage + Cosmic, Wandering Cycles + Cyclic

[Michael Thayne]

Originally Posted by Christopher R. Rice

No. It was a RPM spell and built as a RPM spell. I'd have to dig it out but it was basically internal damage + Cosmic, Wandering Cycles + Cyclic

Ah. Yeah, I think the issue here is more with Wandering Cycles than RPM itself. A good rule is "if you wouldn't allow it as an advantage, don't allow it as an RPM spell". I think PK did pretty good work trying to balance RPM vs. Powers, but given how open to abuse player-made powers are, RPM breaks easily if you don't use the same oversight you'd use with player-made powers. It's basically the same issue as with Modular Abilities (Cosmic Power).

[Christopher R. Rice]

Originally Posted by Michael Thayne

Ah. Yeah, I think the issue here is more with Wandering Cycles than RPM itself. A good rule is "if you wouldn't allow it as an advantage, don't allow it as an RPM spell". I think PK did pretty good work trying to balance RPM vs. Powers, but given how open to abuse player-made powers are, RPM breaks easily if you don't use the same oversight you'd use with player-made powers. It's basically the same issue as with Modular Abilities (Cosmic Power).

It didn't break so much as opened up a bit of a flaw in Cyclic. Though Cyclic needs like 4 eyes next to it. It can be so abused.

[ajardoor]

Originally Posted by Christopher R. Rice

Essentially, a spell that used the Law of Contagion to destroy an entire Cabal. I eventually disallowed it because wow was that powerful only to reallow it using some rules I created to make the cost in line with the effect.

This reminds me of Spatial and Temporal Sympathy Attainments in Mage The Awakening 2e. People complained they were game breakers.

All a Mage with two dots in Space and/or Time needs is an object or a person you've been in contact with (the longer you've been in contact with it, the better, but even something like a pen or a glass you touched for a few seconds can suffice if the Mage is skilled enough or has sufficient Yantras), and suddenly he can use the former to cast spells on you even if you are miles away from him and in a different building, and the latter to cast spells on your past or future self. Seers Prelates from the Panopticon Ministry are even worse, as they don't even need such objects; they have a permanent sympathetic connection with basically everyone, allowing them to spy and cast on whoever they want.