RAW: How to increase height effects of any Area spell?

[hal]

Hello Folks,
After looking at certain area spells with an eye towards a strict interpretation of rules as written, I started looking for official rules that permit a spell caster to increase the effects of an area spell such that it is higher than the initial 4 yards most area spells provide. As such, the following is a list of spells I've been able to find in a seach on "Height" in the PDF. Anyone got other spells they can add to the list, or even a specific mention of a rule that makes it work for ALL area spells cast regardless?

Thanks

WALL OF WIND pg 25
WALL OF LIGHT pg 113
FORCE WALL pg 170
UTTER WALL page 170 (uses FORCE WALL parameters, so included here)
WALL OF LIGHTNING pg 197

These are the only area spells in which the caster can increase the wall height from 4 yards high, to one that is 8 yards high (double cost) to 12 yards high (triple cost) etc. A brief search in GURPS THAUMATOLOGY using the same word, brings up nothing related to area spells as an optional change in the rule.



Note: DESTROY WATER changes the rules affecting the "volume" such that the volume of effect is only 2 yards DEEP, not 4.

[hal]

Note that the wall spells are specifically written to allow for the possibility of extending the wall's effects to higher than 4 yards. What I'm looking for are the rules that permit something like MASS DAZE to have an effect on anything within a given "area" but be able to extend higher than 4 yards.

For instance, suppose you have a round tower that is 30 feet up (10 yards) by 60 yards in diameter. If you cast the spell on the floor level of the round tower, you'd need to cast the spell such that it has a radius of 30 yards (making it an expensive spell indeed!). But it would only affect the people on the ground level, and possibly the second level (assuming 10 foot stories here). In order to cast the spell to get the people on the roof of the Tower (30 feet up remember?), you would have to cast the area spell TWICE - once for the ground level to get Ground level and second floor - and then once again on the second floor level to get second floor and roof level guards.

As best as I can tell, there are no rules that permit one to stack 8 yards or even 12 yards into a single spell casting.

Anyone know where such a rule exists, or is it a "house rule" kind of thing? Just curious.

[whswhs]

This isn't an answer to your general question, but might address the specific case:

Suppose you yourself are standing on the roof of a tall building, one that puts you, say, twenty feet above the ground. You want to cast an area spell on your foes who are also on that roof. Do you need to cast it twice, once for ground level and once for a layer above that? I don't think you should. You certainly ought to be able to cast it at the level of your own footing.

(Compare a different case: If I dig a pit sixty feet deep, can I force every hostile wizard to case a spell five times before the sixth casting is based at the level of the boards I've used to cover the pit? Or can they just choose to cast from ground level?)

Now, it might make sense to say that if I'm on the ground, but I can look up and see the enemy standing on the roof of a tower, I can cast the spell on the tower at the level where they're standing. It would be a bit much, perhaps, to level me cast it at an imagined level of the air, but if there's actually footing there, why not allow it to be based specifically at the level of that footing?

[hal]

Originally Posted by whswhs

This isn't an answer to your general question, but might address the specific case:

Suppose you yourself are standing on the roof of a tall building, one that puts you, say, twenty feet above the ground. You want to cast an area spell on your foes who are also on that roof. Do you need to cast it twice, once for ground level and once for a layer above that?

To answer the question posed here, the rules on area spells are specific: The spell itself is cast upon a surface. If the surface you cast it upon, is on the roof, then it will affect the occupants of the area of your spell's operation - inclusive of the 4 yards between the surface the spell was cast upon, and above that surface. So no, you don't need to cast it twice, once for ground level, and once to be on the surface that you're on. Just cast it on the surface you're on, and presto - spell goes off as advertised.

Originally Posted by whswhs

I don't think you should. You certainly ought to be able to cast it at the level of your own footing.

(Compare a different case: If I dig a pit sixty feet deep, can I force every hostile wizard to case a spell five times before the sixth casting is based at the level of the boards I've used to cover the pit? Or can they just choose to cast from ground level?)

Now, it might make sense to say that if I'm on the ground, but I can look up and see the enemy standing on the roof of a tower, I can cast the spell on the tower at the level where they're standing. It would be a bit much, perhaps, to level me cast it at an imagined level of the air, but if there's actually footing there, why not allow it to be based specifically at the level of that footing?

This is the relevant quote from GURPS MAGIC page 11 under area spells:

"These spells affect an area instead of an individual. They are cast on a surface
– floor, ground, etc. – and their effects extend four yards (12 feet) up from that surface."

That makes me wonder...

Can one cast a spell of a given "area" or radius, on a surface that does not exist? For instance, suppose I'm on the edge of a cliff, and I'm 9 feet from the edge of the cliff. I cast the spell such that its center of area is on me, and the Radius is 6. Does the rest of the spell continue past the edge of the cliff because it is anchored to the surface of the cliff that I'm on, or does it abruptly end because the cliff ends, and the surface does not extend past the edge of the cliff? If I'm on a slope with a rise over run of 1/2 (ie goes up 1 foot for every 2 feet distant) - does the area spell adhere to the surface of the slope, or does it go parallel with the point it was anchored at?

These are all "niggling details" - probably ones that have to be answered by the GM as part of how he sees it in his world. Largely because there is nothing that is stated in the rules as written either way.

RULES AS WRITTEN is a sort of mantra for those who are rules lawyers right? But it also helps formulate how magic works within a game universe. For one GM, it may work as was suggested (Ie it can be anchored to a single point or surface, and overhang it by as much as the spell energy requires it to overhang - or in other game worlds, it ends when the surface ends.

And to clarify better the original question: The idea was to get EVERYONE in the tower with but a single casting. As written, the spell would have to be cast twice to get everyone in the tower. Not that I was implying that you had to do ground level first, then the next level second per se.