Area Effect and Wall height

[Bruno]

Originally Posted by Agent

You make an intriguing case there. Especially if one were trying to hand off a method to the players. Personally, I think I will play around with both methods before deciding one way or another what works for my purposes. Messing with V indeed doesn't terribly appeal to me, but then I haven't really dug into the idea yet, so I'll just have to see.

It's not bad if you're doing computer assisted gaming. You can just shove the formula into Excel or Calc and plug in R and H to find V and a conveniently calculated percentage, for example. Change two cells, new V and new percentage. Ditto with a programmable calculator.

But if someone's waffling back and forth or trying to jiggle a few points out somewhere, and doing it by hand, I could see them getting really annoyed.

It's different if you're aiming for an exact shape and you don't care what it ends up costing you - you don't go back and fiddle with numbers under that circumstance, so you only do the steps once.

Originally Posted by jeff_wilson

A volumetric rule of thumb is: A cylinder, a hemisphere, and a cone of the same circular base and the same height have relative volumes of 1, 2/3, and 1/3. The same ratios hold even if the central height axis is increased (making the hemisphere oblate like a meat patty, or prolate like watermelon) and/or angled to one side (like the shapes were piles of deli sliced meat that was bumped into). You can stack these shapes atop their mirror images and get the same ratios under the same conditions for a cylinder, a full sphere, and a spindle (two cones base to base, like a smooth d10).

Aha, thanks!

Originally Posted by jeff_wilson

IMO, these ratios are not particularly worth different amounts of enhancements since an ability's use case will often exploit the non-zapped adjacent areas for allies or priceless Ming vases to occupy. YMMV.

The same argument could be made for affecting a smaller radius, but GURPS charges you less for that.

[Not another shrubbery]

Originally Posted by Bruno

Where I was going, and I fault myself here for subjecting everyone to a little slice of stream-of-consciousness, is that in a game where it hardly ever matters, I wouldn't make the guy who reduces the cylinder radius to increase the height pay based on the combination of factors - I'd charge him based on the reduced radius and ignore the height. Possibly charge a perk for the "occasionally can make this useful" factor.

I think that many games make the volume of an AE more consequential than its simple area, the idea generally being that the effect needs to extend upward enough to have the potential for Large Area Injury (for attacks) or provide overhead cover (for defenses). If a player wants to manipulate the area affected by an ability (during character creation) in a way that leaves the volume constant, I would assume that they either are building to concept or have a clever use in mind that probably will not get exploited often.

Otherwise, in games where there are flying PCs and NPCs engaged in 3-dimensional tactical maneuvering (superhero games, games featuring a lot of aquatic species and under-water combat, and some kinds of fantasy games) are the kinds of games where I think someone has to pay somehow for that extra dimension. Keeping the volume constant certainly works, but I think most people would be happier to be charged by R and H rather than by V and have to back-calculate. You also get shapes easier to fit into game-friendly units - circles and hexagons are a little annoying to math out.

I would just keep it simple and allow the height to be quadrupled while halving the radius.

[Bruno]

Originally Posted by Not another shrubbery

I think that many games make the volume of an AE more consequential than its simple area, the idea generally being that the effect needs to extend upward enough to have the potential for Large Area Injury (for attacks) or provide overhead cover (for defenses). If a player wants to manipulate the area affected by an ability (during character creation) in a way that leaves the volume constant, I would assume that they either are building to concept or have a clever use in mind that probably will not get exploited often.

Area Attacks already pretty clearly qualify for Large Area Injury (or I thought they did - they seem to be pretty classic examples of it) and I honestly can't think where a straight, non-Wall Area doesn't provide it's normal advantage or effect from overhead, unless limited to not provide it. Obscure obscures from all angles, Illusions are illusionary from all angles, and Temperatures remain controlled regardless of your angle of entrance into the area.

And Walls already allow for stacking or making into funny shapes.

My brain is full of perl code and the guts of AFP files right now, so I'm feeling very blurry, but I guess I'm just not quite seeing the point other than "Affect more targets"

Originally Posted by Not another shrubbery

I would just keep it simple and allow the height to be quadrupled while halving the radius.

How is that simpler than just setting radius and height?

[Not another shrubbery]

Originally Posted by Bruno

Area Attacks already pretty clearly qualify for Large Area Injury (or I thought they did - they seem to be pretty classic examples of it)...
<snip>
My brain is full of perl code and the guts of AFP files right now, so I'm feeling very blurry, but I guess I'm just not quite seeing the point other than "Affect more targets"

They do. The point I was trying to make was that you cannot pay attention solely to the radius of an AE and assume that the height is inconsequential (not to say that you were, BTW). Frex,if you cut the height down to two yards, some effects might be avoidable for the very tall, and at one yard some might do little or nothing to most targets. This points us to analogous situations where the character with the taller but skinnier AE might find use for his variant... dealing with giants, foes up in the treetops, etc.

How is that simpler than just setting radius and height?

Simpler for me, I should have said :) The alternative would involve a lot of square root calculations, and figuring out how the odd-sized radius would look on a hex map.

[Bruno]

Originally Posted by Not another shrubbery

Simpler for me, I should have said :) The alternative would involve a lot of square root calculations,

I'm sorry to harp on this point, but why are you doing square root calculations? You don't need to know the volume if you know the radius and height.

You determine if the possible subject is within Radius hexes of the origin, and within Height hexes of the origin (assuming you're measuring orign from the bottom or top of the cylinder). No square roots involved at all.

Originally Posted by Not another shrubbery

and figuring out how the odd-sized radius would look on a hex map.

And now I'm REALLY lost - how does changing the height make the radius somehow different from the standard AE enhancement?

[Refplace]

Originally Posted by Bruno

I'm sorry to harp on this point, but why are you doing square root calculations? You don't need to know the volume if you know the radius and height.

You determine if the possible subject is within Radius hexes of the origin, and within Height hexes of the origin (assuming you're measuring orign from the bottom or top of the cylinder). No square roots involved at all.



And now I'm REALLY lost - how does changing the height make the radius somehow different from the standard AE enhancement?

Well if your assuming that a higher ceiling means smaller radius because you must retain the same volume I can see that.
But I prefer the enhancement upping the height option for simplicity.

[Not another shrubbery]

Originally Posted by Bruno

I'm sorry to harp on this point, but why are you doing square root calculations? You don't need to know the volume if you know the radius and height.

You determine if the possible subject is within Radius hexes of the origin, and within Height hexes of the origin (assuming you're measuring orign from the bottom or top of the cylinder). No square roots involved at all.



And now I'm REALLY lost - how does changing the height make the radius somehow different from the standard AE enhancement?

Originally Posted by Refplace

Well if your assuming that a higher ceiling means smaller radius because you must retain the same volume I can see that.
But I prefer the enhancement upping the height option for simplicity

Refplace has it. I am assuming that the volume is fixed for a given level of AE, so that to increase the height by a factor of X, you need to reduce the radius by a factor of |sqrtX|.

Obviously, I will not be getting any articles approved for publishing anytime soon... I learned at the same school as Calvin :/

"I realized that the purpose of writing is to inflate weak ideas, obscure pure reasoning, and inhibit clarity."

[Bruno]

Originally Posted by Not another shrubbery

Refplace has it. I am assuming that the volume is fixed for a given level of AE, so that to increase the height by a factor of X, you need to reduce the radius by a factor of |sqrtX|.

Volume is only fixed for a given level of AE because there's no way to adjust height. Keeping volume constant to fiddle with height requires crazyness, I totally agree.

So why not add in a second modifier to adjust height, separately from radius, and let the approximation of volume go hang?

Ie, +50%/level for each doubling of radius at 4 yards of height, +25%/level for each doubling of height? That way you don't have to backfigure anything, which is what's got me boggled about your system.

Originally Posted by Not another shrubbery

Obviously, I will not be getting any articles approved for publishing anytime soon... I learned at the same school as Calvin :/

"I realized that the purpose of writing is to inflate weak ideas, obscure pure reasoning, and inhibit clarity."

I think we're both talking past each other, because we're both accusing the other person of the malicious use of square roots with intent ;)

EDIT: because I'm being a poor communicator again, what I'm attempting to say is that I think I'm communicating pretty darn poorly myself.

I wonder if we can get a group discount on communication therapy?

[Refplace]

Originally Posted by Bruno

So why not add in a second modifier to adjust height, separately from radius, and let the approximation of volume go hang?

Ie, +50%/level for each doubling of radius at 4 yards of height, +25%/level for each doubling of height? That way you don't have to backfigure anything, which is what's got me boggled about your system.

Thats my preference too. Since with a few enhancements you can modify it anyway you want and get far more area for your buck all the time I think 25% is high for doubling height.
Most of the time that wont be much use so I propose +10% for each doubling of height. or maybe a +50% Increased ceiling which doubles with normal increased area.
I think that would be fair since that would be *32 under the 10% plan.
Also a 60% Wall Enhancement would allow you to stack heights already which would also benefit from the increased area of multiple levels of Area Effect.
And the 60% Wall Enhancement gives much more flexibility.

Originally Posted by Bruno

I wonder if we can get a group discount on communication therapy?

Hey I want in on that too!

[jeff_wilson]

Originally Posted by Refplace

Thats my preference too. Since with a few enhancements you can modify it anyway you want and get far more area for your buck all the time I think 25% is high for doubling height.
Most of the time that wont be much use so I propose +10% for each doubling of height. or maybe a +50% Increased ceiling which doubles with normal increased area.
I think that would be fair since that would be *32 under the 10% plan.
Also a 60% Wall Enhancement would allow you to stack heights already which would also benefit from the increased area of multiple levels of Area Effect.
And the 60% Wall Enhancement gives much more flexibility.

If you allow doubling of height for +10%, then Wall +60% will allow you to reshape it into a low, thick wall, getting the quadrupling effect of Area Effect +50% for only +20%. You'd only have to do this twice to make up for the Wall +60%, then not only does your volume affected expand much faster, the rate of increase increases 8 times faster for the same points.

A tall and wide permeable Wall that engulfs the earth is normally about 67 applications of Area Effect for a total modifier of about +3400%; doubling height for +10% lets you do it for +730%.