Draw Power at TL3

[ErhnamDJ]

Originally Posted by Fred Brackin

No. by the terms of the 4e spell the energy has to be accessible to a machine of that TL. You've got no way to get energy out of your giant cylinder.

I thought the cylinder was a way of getting energy out of the falling balls. The cylinder is the machine that accesses the energy from the balls.

When you try and introduce a draw off mechanism whether it be a camshaft or a rope or whatever you run into the limits of materials science for that TL.

Isn't the cylinder drawing off the energy from the falling lead balls?

If I have a steam engine that turns a wheel, I can use the spell on that. But if I have a gate mechanism that drops lead balls and turns a cylinder, I can't use the spell on that?

I have a machine set up that moves a cylinder. How is that not a "tool that uses, stores, or transforms power in order to do its job?"

It's using the energy from the falling balls to turn a cylinder. Does the cylinder have to turn something else? We can have the turning cylinder that sits on some force walls and spins in place, with gear wheels on the end, with another cylinder that sits on top of it, on more force walls, where the bottom cylinder gets turned by the dropping balls, and that, in turn, spins the other cylinder.

I guess I just don't understand what the spell wants my machine to be in order to get the power out of it. How many gears do I have to connect together before I can get the power out of it?

[ErhnamDJ]

Originally Posted by Ze'Manel Cunha

This is GURPS, when the given doesn't match the setting, we change the given. *grin*

This is GURPS, where we can always come up with a setting. I could definitely imagine something like The Dying Earth, where the technology has fallen away, but the wizards still have their old spells.

I could even combine that with 2001 to get a workable story. It turns out they were seeded with these spells in order to test them, and this is part of them becoming gods. They are just now beginning to harness their true potential, and soon they will meet their makers. *grin*

[fschiff]

Aren't there magical engines in one of the Spaceships books?

If you can put that kind of engine in a spaceship or an airship, can't you put it on the ground (or in a volcano, etc.)?

[Fred Brackin]

Originally Posted by ErhnamDJ

I thought the cylinder was a way of getting energy out of the falling balls. The cylinder is the machine that accesses the energy from the balls.

What is the useful work the cyklinder performs? None that I can see.

I think you're still looking for a hole to pour energy into. That's not what you need.

[whswhs]

Originally Posted by ErhnamDJ

I have a machine set up that moves a cylinder. How is that not a "tool that uses, stores, or transforms power in order to do its job?"

No, you don't have a machine. The balls are not continuing to fall like that through a purely physical, natural process, but as a result of magic. That is, you're using magical energy to cast a spell that produces physical effects that are then converted into magical energy. GURPS doesn't allow that sort of trick. There are spells in GURPS Magic that could arguably be used to do that, and it's explicitly disallowed.

Bill Stoddard

[ErhnamDJ]

Originally Posted by Fred Brackin

What is the useful work the cyklinder performs? None that I can see.

Are you asking why someone would build this machine? It provides energy through the Draw Power spell.

It looks like it fits the definition of a machine, as given by Magic:

Originally Posted by GURPS Magic

For the purpose of these rules a machine is a tool that in some way uses, stores, or transforms power in order to do its job. Thus a hand drill doesn't qualify , but an electric drill does.

How does my proposed machine differ from an electric drill?

I have a large bronze cylinder supported on force walls. Lead balls drop down from the sky and turn the cylinder.

If I stick a drill bit out the end of the cylinder (or mold it in that shape), then would you let me get the energy from it? Does a water wheel have to have some drill bit to count for the spell?

If it needs to continuously spin, then I can have it be a gear wheel that turns, which turns the cylinder and spins the drill bit sticking out.

I don't see how balls dropping is any different from how the combustion in an engine goes off and pushes a pistol. Rather than lots of little explosions, mine uses lots of balls being repeatedly dropped.

I think you're still looking for a hole to pour energy into. That's not what you need.

I don't know what that means.

But here's how I see my cylinder:

It's just like a water wheel. There's a constant flow that pushes the wheel. Only, the flow is lead balls rather than water molecules. The impact of the balls pushes the wheel and turns it. The difference is that my bronze cylinder is sturdier than a wooden wheel.

I really don't see why a spinning wooden wheel powered by water molecules works for the spell, but a spinning bronze cylinder powered by lead balls does not.

[ErhnamDJ]

Originally Posted by whswhs

No, you don't have a machine.

It looks like it meets the book's definition of the word.

The balls are not continuing to fall like that through a purely physical, natural process, but as a result of magic. That is, you're using magical energy to cast a spell that produces physical effects that are then converted into magical energy.

They are falling through a physical force: gravity. All the magic is doing is creating a gateway. It would be the same if I had a workforce of rukhs dropping the balls. But that doesn't really matter for the point you're trying to make, does it? Because you would object equally to me using Create Animal to get rukhs to drop the balls, right? Or gorillas from the spell in place of your example oarsmen, right?

GURPS doesn't allow that sort of trick. There are spells in GURPS Magic that could arguably be used to do that, and it's explicitly disallowed.

Where is it disallowed? I was looking into some of the other possibilities, but if none of them are going to work (the Heat spell, say), then it's just not going to be possible. There's going to have to be magic involved somewhere in here. Or he's going to have to get lucky and find a naturally-occurring wormhole to fill in for the magical gateways. Which might be possible, with judicious uses of knowledge and teleport spells. But I don't think knowledge of wormholes is TL3.

[whswhs]

Originally Posted by ErhnamDJ

They are falling through a physical force: gravity. All the magic is doing is creating a gateway. It would be the same if I had a workforce of rukhs dropping the balls. But that doesn't really matter for the point you're trying to make, does it?

That gateway teleports the balls to a higher location and therefore increases their potential energy. Therefore you're turning mana into physical energy, and turning physical energy back into mana.

Of course, there is one way around it: You could argue that the two ends of the gate are in fact at the same gravitational potential. But if that's true, I expect the gravitational force between them would be zero. Which means that if you put anything in between them, it would not accelerate downward. You'd have a levitation spell, in effect. And then you wouldn't get any work out of it.

Bill Stoddard

[ErhnamDJ]

That gateway teleports the balls to a higher location and therefore increases their potential energy. Therefore you're turning mana into physical energy, and turning physical energy back into mana.

But the energy doesn't come from the spell. It's just like if I nudge a tungsten rod into the earth's gravity. It doesn't mean I'm Superman when it explodes on impact. The spell isn't what's acting on it, the earth's gravity is.

If I set up the portal so the ball falls into Superman's hand, and he then throws it, is it the spell providing the energy in that case?

And I still fail to see how it would even matter if it really was the spell providing the energy, like with the Heat spell. If I use the Heat spell to make something hot, and then pour water over that hot thing, and then I run my steam engine using that steam, why would Draw Power not give me my power from it?

I realize this is almost never going to be applicable. I can't imagine any GM actually allowing any of this without having the whole campaign based around it, but the rational I would expect for disallowing it would not be that that's not how the spell works.

Originally Posted by whswhs

Of course, there is one way around it: You could argue that the two ends of the gate are in fact at the same gravitational potential. But if that's true, I expect the gravitational force between them would be zero. Which means that if you put anything in between them, it would not accelerate downward. You'd have a levitation spell, in effect. And then you wouldn't get any work out of it.

Well, I could have them both in the same level of gravity, but have the exit end be close enough to a gravitational field that I could have someone standing there to push the balls into the nearby gravity well. I'd probably use a spring and call it Galactic Pinball.

[whswhs]

Here are two technical points about machines:

The point that you can't use magic to create physical energy that is then turned into magical power:

See the spell Create Fuel on p. 179, which says, "Other Energy spells such as Steal Power or Draw Power cannot tap magically created fuel or a machine using created fuel for energy.

The definition of "machine":

On p. 175, a definition is given: "A machine is a tool that is some way uses, stores, or transforms power in order to do its job. Thus, a hand drill doesn't qualify, but an electric drill does. A spring-powered pocketwatch is a machine, while a sundial is not."

On p. 178, "'power' means any energy used by a machine to do its job. At TL8, this generally means electricity. Earlier TLs might use mechanical power from a waterwhell or steam engine. . . ." On p. 180, under Conduct Power, we see "Conduct Power may tap into mechanical energy from natural sources." The "natural sources" is vital; if you set up a gate, and it teleports lead balls above the machine, the potential energy they gain from increased altitude clearly does not come from a natural source.

The intent of these rules is quite clear: You can convert energy from purely natural sources into a form that can power a machine to perform some useful function, and then convert the power into mana. But if the energy is provided through the casting of a spell, then you can't turn it back into mana. There is no magical perpetual motion. It doesn't matter how fancy your descriptions get; the effect is that you can get out more mana than you put in, and that's prohibited. There ain't no such thing as a free lunch.

Bill Stoddard