Questions about Innate Attack (Wall)
 

EDIT: Note this thread has been raised from the grave by necromancy most foul. New posts start at #9.
EDIT2: Even fouler necromancy has raised this thread yet again; new posts start at #37.

Alright, so the recent Wall thread is making me wonder quite a few things about the Enhancement that I'm hoping to get clarified. Note for the following questions I'm referring to "Innate Attack with the Wall Enhancement" as simply "Wall."

First, height. Do Walls follow the general GURPS trend of having each hex be essentially a 1 yard wide by 4 yard tall hexagonal prism? If not, how tall are they meant to be? Can we reorient them to lay on their sides, or particularly with the +60% version thin them out to get more surface area out of them (while maintaining the volume)? And why are hexes 4 yards tall to start with?

Next, shells. How exactly should one go about using Wall to build a shell - that is, a wall with a roof? The way I handle it, you need full sized walls for a base, then more on top, and then you can fill in the empty space on the second level to make the roof. Is this correct? Note this requires 13 hexes to build a shell over a 1 hex "room." On that topic, how do you have a Wall that can manifest underground, so that foes can't simply dig their way into or out of a shell?

Another question would be climbing. When a Wall is defined as being rigid, how difficult should it be to climb it? Would it be appropriate for such Walls built from Cutting/Impaling attacks to risk cutting the character as they climb? And how would we adjust difficulty, if there's one character who makes walls of rough stone and another who makes them of mirror-polished metal?

Yet another for rigid walls would be weight. Should walls be considered as having a weight, and if so, how much? Is this a case where we should simply back-calculate from HP, assuming a homogenous target? PK had a great suggestion here for determining how much weight a Wall can support, but it also seems like a terribly strong foe might be able to pick up and throw a Wall aside, rather than smashing through it, so a weight for the actual Wall might be appropriate.

And how about hybrid walls - say, a wall of crushing force that deals damage to those who try to pass through it and requires them to physically break through? I think the RAW would be to build two different Wall abilities and Link them together, but would it be legal to have them exist in the same hexes?

Related to that, how about transparency? Is transparency/opacity a Feature? What about a Wall that is, say, opaque to visual light, but transparent to IR?

EDIT: From the other thread, do walls - be they permeable or rigid - require contact with the ground, or could they be made to simply hover in the air until they expired or were destroyed?

And one I had initially forgotten about - do walls have a minimum thickness, and if not, when making them thinner than 1 yard, can we use that volume elsewhere or is this a case where you are basically just condensing the wall down? If we can use it elsewhere, would it be appropriate to scale damage/DR+HP linearly with thickness?

I'll probably think of more later (I thought I had others earlier, but can't remember them now), but some answers on what I have above would be greatly appreciated.

Re: Questions about Innate Attack (Wall)
 

I agree that Walls should be 4 yards tall, as per the usual Area of Effect rules. I'd argue that the +60% version of Wall, that lets you shape the effect, should include whether the wall is vertical or not. Since each chunk of Wall gives you 12 square yards of area to play with, I guess enclosing an SM 0 individual in a sphere would thus require 3 "Wall units", since a sphere with 1.5 yards of radius has a surface area of 28.26 square yards. And a 2-yard high hemisphere still needs just over 24 square yards, so it still needs 3 Wall units too.

Re: Questions about Innate Attack (Wall)
 

12 feet is 4 yards, the 12 foot rule was cited in the other thread iirc.

Re: Questions about Innate Attack (Wall)
 

I assume by "wall units" you're referring to the 3x4x1 yard chunks that each yard of radius on the area effect gives you? In that case, yeah, I could see a 3 yard radius working, although personally I think that's a bit low, and would be tempted to require 5 (2 to surround the target, 2 to build on top of that surrounding wall, then 1/3 of a full unit to fill in the empty spot above the target; the remaining volume might be usable to strengthen the wall a bit).

...

The other thread brought up another question, which I'll also add to the original post - do walls, permeable or rigid, require contact with the ground at some point, or can they be made such that they simply hover in the air?

Re: Questions about Innate Attack (Wall)
 

Yes, sorry, that's what I meant. I was trying to find a useful shorthand, but failed to explain that.

The thing is, the +60% version of Wall says that you can "form it into any shape you choose". I don't see why that shouldn't include shaping a vertical wall into a curve.

With all the math apps and such available online or on smartphones or whatnot these days, I think it's actually easier to do the math of "what's the area of the shape you want to cover, ok now divide that by 12 square yards, that's the size of the Wall you need to cover it", rather than trying to figure out "ok, how many Walls do I need to make this flat section, then this section, then that one...".

In another thread where we were discussing this, I came to the decision that by default, a Wall needs at least one anchor point. If you take the Drifting enhancement, you can create it floating in midair, and "drift" with gravity - i.e., falling down and possibly crushing anyone it lands on. I'd also allow a "Hovering" enhancement for +10%, that let you create the wall at any point, without an anchor, and then it would just stay there without moving.

Re: Questions about Innate Attack (Wall)
 

"Other people" was just you.

Re: Questions about Innate Attack (Wall)
 

I don't think you need an app, the area of a half-sphere is 2(pi)r^2. So you need a wall with area [(pi)r^2]/6 to make any half-sphere of radius r in yards with the +60% Wall (note that if you plan to stand in the center, r should be at least your height).

Re: Questions about Innate Attack (Wall)
 

That's fine, just wanted to make certain I understood your intent.

With a battlemap, it's easier to simply do things a hex at a time, as then there's no confusion about exactly where the Wall blocks (with a hemisphere, you're only taking up part of each hex, so it's hard to say if such can be entered/occupied by a character or not). Without a battlemap, I don't think there's likely to be any serious problems with allowing for hemispheres and the like (although I might still require the enclosed area to be 4 yards tall, for more of a hemiellipsoid).

Thanks, that thread, while not official, gives some pretty solid options. I don't think I'd allow Drifting to cause damage from a fall (although with the low HP of walls - only 1 per 2d - it's unlikely to be a serious problem), however, so I'd be tempted to price it and Hovering at the same value - each has advantages and disadvantages to its use (Drifting can let you drop a line of walls to block off or give protection to an area that is outside of your Range, while Hovering lets you create better aerial barriers/hazards). Maybe call it No Anchor, with Drifting or Hovering in parenthesis. +20% sounds about right.

Also, the mention in that thread of making an ice wall underwater sort of gives me a solution to the underground problem. For the underwater wall, you simply need to give it the Underwater +20% Enhancement. Underground is similar, but of course forming within a solid should be harder than forming in a liquid, so I'm thinking +50% (same as Adding Utility with Cosmic, which also seems about right).

An app or spreadsheet or similar might speed things up compared to inputting that in a calculator (although rounding that down to (r^2)/2 would probably get you close enough and be quick to do). Additionally, sometimes you might want something other than a hemisphere, in which case an app might be useful. Still, while spheres and the like may be doable, I honestly favor the hex approach, so I'll stick with that.

...

So, here's how I think things should work for each of my questions. Let me know if anything here contradicts RAW.

Height was answered by Bruno in the other thread, and is indeed 4 yards. The +30% version is stuck with walls that are 1 yard thick per 1d and always 4 yards tall (for taller walls, build on top of the initial one), but I think I'll allow the +60% one to be arbitrarily thin, allowing them to be spread out. When doing so, you need to adjust DR and HP linearly.

For shells, I'm going to stick with my hex-based approach. Optionally, when filling in the empty slot on top, you don't need to build an entire second level for the wall - you may instead have each "roof hex" take up two hexes worth of wall, which covers both that section and the connections to the other sections. A Wall that is able to manifest underground (but note this doesn't damage anything down there, and things return to normal once the Wall expires or is destroyed) needs an Enhancement, Underground +50%.

For climbing, you may set a modifier between -4 and +4 as a Feature. If you can choose the modifier when you create the wall, that's a +20% Enhancement. The GM may allow for greater penalties or bonuses - +5% per additional -1 (maximum +30% for -10), +10% for +5 total, +20% for +6 total, or +30% to require no roll (Wall functionally has a built-in ladder). Climbing a sharp wall requires a Climbing roll every second or suffer thr/2 (use climber's HP as ST, damage cannot exceed nominal damage for Innate Attack) cutting damage to the arms. This can be avoided by going at half speed, or by wearing sufficient protection to avoid damage.

Walls are functionally weightless - you need to break through them (at which point the destroyed section ceases to exist) and cannot pick them up.

For hybrid walls, I'd say it should be fine to allow overlap. In fact, I'd simply define part of the Wall's damage as rigid (for determining DR and HP) and part as permeable (for determining damage dealt).

Walls are by default visible but don't impede vision - you don't need to worry about accidentally running into one, but at the same time there's no penalty for looking through one. To change this, you need to Link Obscure (Vision) to the Wall. If you want a truly transparent Wall, I'd argue for Surprise Attack - and if you don't want anyone to notice that you're doing something (even if they can't see the Wall), you'll also need No Signature. Being able to see your own invisible wall (and/or those of your close allies - that is, others in the party) is a Perk.

Walls by default require contact with an "anchor" of some sort - at the very least, they need to be connected to the ground on each end of the wall (or possibly in the middle, provided the result is balanced). Avoiding this requirement calls for an Enhancement, No Anchor +20%. You must choose between No Anchor (Drifting), in which the Wall will drift based on magnetic fields, gravity, or similar (set it when creating the Advantage), and No Anchor (Hovering), in which the Wall will simply hover in a set location in the air. No Anchor (Variable) +30% may also be available, letting you set if a given Wall drifts or hovers when creating it.