[Black]

Hi All, just a few questions on Physical Barriers.  Please correct me if I am wrong or clarify anything which is unclear. Thank!

Shape
The spell can be either a dome or a wall.  Can it be a cylindar shaped wall? 
How do we determine hieght and length? 
Can I create cylindar shaped wall? 
If I am inside, can I make the wall hight less then a foot from the roof (to allow throwing grenades etc over the wall?
Can I create a ramp, or a bridge?  say 1 meter wide and 12 meters long (with a force 6 spell)

Visibility
Is it a flat -1, or -1 per a structure rating, or -1 per a Force?  Would a really powerful wall be harder to see through?

Setting Size (mostly from SR4Ap183)
Size is determined before casting and is based on Force meters radius.  So a force 6 force wall is by default 6m radius (12 meters long for a straight wall).
This is radius hieght  as well?  eg Force 6 wall will be 12 meters long and 6 meters high (of is that 12 meters high?)
If the wall is too big for its surroundings, does the wall or the surroundings lose?  (My guess is the wall will conform to its surroundings...)
I can reduce the size, before casting, by reducing the dice pool by 1 dice for every meter reduced. (SR4Ap183).  This also applies to increasing the size. 
This dicepool reduction also reduces my drain dice as well. (ouch!)
Example, I want a 2m radius barrier with a Force 12 spell, 6 magic, 6 spellcasting (dIcepool 12-10 meters = dicepool 2, for both spell casting and drain...ouch... only 2 dice means that the structure rating is 2 max... but the drain is f/2+3=9... also resisted by 2 dice).

Changing Size/Shape
Once cast, can you change the size/shape of a Physcial Barrier?
Can you *squeeze* people with a barrier?

Moving the Wall
Can you move the barrier, like a wall moving down the corridor, pushing the enemy back, or even squishing them in a real physical wall?
Can you carry people with a wall, slowling moving it like it was a flying carpet?

[cr4kp0t]

I'll start responce by putting up the spell as it shows in SR4A.

Physical Barrier (Environmental, Area)
Type: P • Range: LOS (A) • Duration: S • DV: (F ÷ 2) + 3
Barrier spells create glowing, translucent force- elds with both 1 point
of Armor and Structure rating per hit (see Barriers, p.194).  e caster
can form the barrier as a dome with a radius and height equal to the
spell’s normal radius.  The caster can also form a wall with a height and
length equal to the spell’s Force.  e caster can adjust size of the barrier
the same as the radius of an area spell (p.183).
Physical Barrier creates a physical wall. Anything the size of a molecule
(or less) can pass through the barrier, including air or other gases.
Anything bigger treats the barrier as a normal physical wall. Attacks
directed through a barrier have a –1 dice pool visibility penalty.  e
barrier does not impede spells.  e barrier can be brought down by
physical attacks, but as long as it is sustained it regenerates damage
quickly—any reductions in Structure Rating are restored at the beginning
of the next Combat Turn. If the barrier is penetrated, however,
it collapses and the spell ends. Physical Barrier cannot be used on the
astral plane.

So to answer a few of the questions.

It simply says it must be a wall it doesn't say that the wall has to be flat so yes in theory you can create a cylinder provided that the circumference of the base is no longer than the length you can create.

As the spell is an areas spell then yes you can a just the height of the 'wall' with the usual penalties so -1 per meter or fraction thereof. If this is to allow grenades in i would point out that simply putting the barrier up afterwards is more effective and at worst would mean the mage delaying their action.

The ramp. with RAW to create a ramp 12m X 1m form a force 6 spell would incur a - 11 modifier ( -5 for reducing the 'height' and -6 for extending the length)

However in my games i rule that the barrier can either create the dome/ sphere as advises or a surface with an area of force squared.

The -1 modifier as shown in the spell description has no reference to force or hits so is a flat -1.

You have the bit about length of the wall incorrect a force wall would have a length of 6m and a height of 6m.

You asked about if the wall is too big for it's surroundings. I can two obvious interpretations. 1. as stated that the wall conforms to its surroundings. or 2. that the barrier actually passes through wall eg. if there 2 corridors adjacent to one another that are both 3 m wide a force 6 barrier would block both of then. assuming a negligible thickness of intervening wall.

let me copy in the section of reducing dice pool for area spell it will amke the next bit easier to answer.

 The caster can reduce or expand
the base radius by 1 meter for every die withheld from the Spellcasting
Test. Dice expended to change the radius of the effect cannot be used in
any related test, such as resisting Drain for that spell.

This doesn't mean that you lose the dice from both pools only that the dice lost from the spell-casting pool are just that lost and can't be added or used on any other test. this is in reference to an old rule from previous editions where you could withhold dice from the spell casting test  to help resist drain. this was removed in SR4 however there are many erroneous references to it through out the books. incidentally a lot of people i knoww still use this as a house rule though.

last but not least moving and shaping the barrier once cast.

[quote author = sr4a p184]If an area-effect spell is sustained, the area effected area may be moved
with a Complex Action, as long as it remains within line of sight.
Characters who “drop out” of the a effected area are no longer affected
by the spell; characters who are “enveloped” by the area must defend
against the e ects of the spell as appropriate.[/quote]

So put simply no you couldn't re-size the barrier once cast.

However you could move it. it would be up to GM to decide  how a barrier moved whether it traveled or just reappeared in its new location.

But yes in theory you could use a physical barrier as wall crushing trap with a bit of GM nicety. the question would be how to resolve the 'attack' and whether the barrier could withstand the crush itself.

IMO it would be an opposed test of the barrier's 'strength' vs the characters strength +body. with net hits being damage caused by crushing. this assumes of course that the other wall doesn't just crumble.

[Black]

Thanks Cr4kp0t.  Very much appreciated.

I was using the area effect rule (area = force radius meters), and completely missing the clear description of the spell which says

The caster can also form a wall with a height and length equal to the spell’s Force.

So my bridge example should say '6m by 1 meter'... which, thanks to your clarification, would result in a -5 dice pool for reducing the 'width/hieght' of the wall.

I would rule, in my game anyway, that the barrier conforms the surroundings with no dicepool penalty to the caster.  The idea that the physical barrier might go 'through' the wall into an adjacent corridor breaks, in my opinion anyway, the line of sight rule for spellcasting

Quote from:  sr4a p183

     The caster can reduce or expand
    the base radius by 1 meter for every die withheld from the Spellcasting
    Test. Dice expended to change the radius of the effect cannot be used in
    any related test, such as resisting Drain for that spell.

This bits confusing and needs an errata.

Thanks cr4kp0t!

[cr4kp0t]

Glad to be of assistance.

[Falconer]

Disagree.  The rules are unclear so it's up to the GM... however... there are certain things in shadowrun which have always been held constant.

Shadowrun has certain tropes... and one of those tropes is that spells have very limited shapes.  It's not DnD with cones spreads etc. etc. etc.   I actually kinda like this as it limits mages a bit.

Area spells ALWAYS encompass a spherical/dome area unless they say otherwise.

Barriers allow you to make a wall instead.   I wouldn't allow them to shape it further.    If they wish a circular area that's what a dome is for.    If they want to turn the all on it's site horizontal... angled... whatnot... great.

However a physical barrier as a ramp I'm not certain can support anything.  Look at the magical barrier rules... if you try and use one to hold something up it collapses.  Hell if anything goes through it at all... it pops like a balloon.  (and you'll practically never get more than 5-6 successes barring the earlier ludicrous edge example).


That's just me.   If you allow magic to be too free form you end up with "Mage" where most games turn into arguments about the extent of what this many dots of magic allows.

[ArkangelWinter]

However a physical barrier as a ramp I'm not certain can support anything.  Look at the magical barrier rules... if you try and use one to hold something up it collapses.  Hell if anything goes through it at all... it pops like a balloon.  (and you'll practically never get more than 5-6 successes barring the earlier ludicrous edge example).

That's just me.   If you allow magic to be too free form you end up with "Mage" where most games turn into arguments about the extent of what this many dots of magic allows.

Not allowing the ramp sounds to me like punishing creativity. You can drive a small car up a fiber-board ramp if you have to in reality (albeit carefully), and thats certainly not even Barrier Rating 6. All the barrier has to do is be close to as sturdy as a 2x4 wood plank. Because the spell description doesnt mention the player getting to choose slanted, I'd probably houserule that required an Edge or for the caster to move the barrier to slanted after casting.

[Falconer]

That's a fair criticism Ark....

Like I said... I don't know.  The physical barrier is NOT a mana barrier/ward... and actually does get a structure rating... so I'm not really all that hostile to it.

My gut instinct when it comes to magic is to immediately read it in a restrictive way for sake of balance though.  It's one thing to reward creativity... another when only the mage can repeatedly pull rabbits out of his hat because his spells give him a degree of flexibility far and above that available to the other non-magical players.

[Black]

Something which just occured to me...  If a barriers armour and structure rating is based on hits... and Force is just to get the radius/length of the barrier... It makes sense to cast this at low force rather then reducing the size (and lossing dice for the roll)

Eg in the original example, for a 2 meter radius dome, you should cast at force 2 only.  Sure, have the dicepool at 12 + Edge to ensure that the wall is strong, but only cast at force 2.

Thats right isn't it?

[Mirikon]

Because your hits are capped by Force. Force 2 spell can only use 2 hits, no matter how many you roll.

[Black]

Because your hits are capped by Force. Force 2 spell can only use 2 hits, no matter how many you roll.

Ouch.  So if you want a small, but powerful wall, you need to cast it with high Force, but then drop a large number of dice from the dicepool to reduce the size.  Sounds a bit... well not good for the caster.

[Black]

Update of my understanding.  Mostly RAW, some houserulling:

First, lets look at the rule book (SR4A p.211):

Physical Barrier (Environmental, Area)
Type: P • Range: LOS (A) • Duration: S • DV: (F ÷ 2) + 3

Barrier spells create glowing, translucent force-fields with both 1 point of Armor and Structure rating per hit (see Barriers, p. 194). The caster
can form the barrier as a dome with a radius and height equal to the spell’s normal radius. The caster can also form a wall with a height and
length equal to the spell’s Force. The caster can adjust size of the barrier the same as the radius of an area spell (p. 183).

Physical Barrier creates a physical wall. Anything the size of a molecule (or less) can pass through the barrier, including air or other gases.
Anything bigger treats the barrier as a normal physical wall. Attacks directed through a barrier have a –1 dice pool visibility penalty. The
barrier does not impede spells. The barrier can be brought down by physical attacks, but as long as it is sustained it regenerates damage
quickly—any reductions in Structure Rating are restored at the beginning of the next Combat Turn. If the barrier is penetrated, however,
it collapses and the spell ends. Physical Barrier cannot be used on the astral plane.

Lets clarify this further:

Shape

The barrier is typically either a dome or wall.

The dome will have a radius equal to the Force of the spell.

The wall will have a length and height equal to the Force of the spell.  This, initially gives it a 'square' shape.

The 'wall' can be shapped like a cylindar, bridge or ramp etc.  As long as the size remains the same...

The wall or dome will conform naturally to the shape of their surroundings and not 'breach' existing physical barriers. eg a physical barrier with 6 meters length cast in a 2 meter hallway will end at the walls of the hallway, not continue into surrounding rooms etc.

The caster, before rolling the dice, can change the size of the dome or wall....

Each metere increase or decrease to the shape will reduce the casting dice pool by 1.

It may be easier to set the force appropriatly, but not in every situation.  Eg, you want a 'bridge' that is 6 meters long, but only two meters wide?  Either cast at force 6 and have a bridge that is both 6 meters long and wide, or reduce your dice pool by 4 to represent shaping the wall down to 2 meters wide.

Or perhaps more relevant, the 'chunky salsa' container at last game could have been cast a Force 12 (to create a cylindar with a 2 metre radius), but then the 'height' of the cylindar would need to be reduced to less then 3 meters (to create the 'gap' used for the grenade), resulting in a -9 dice pool for casting... ouch.

Visibility

The wall provides a -1 visibility modifer.  Spells can be cast through the wall with this -1 penalty.

Strength of the Wall

The Armour and Structure rating of the wall is equal to successes rolled by the spellcaster, not the Force.  Force however determines the number of successes which are counted (The hits scored on the Spellcasting Test may not exceed the spell’s Force, SR4A p.183) and determines size...

Walls are damaged per the Barrier rules.  Therefore, for example, explosives like Flash Bang grenades do DOUBLE damge! wow!  Rules are located SR4A p.166.

The wall is destroyed if its Structue rating is reduced to 0.  The wall regenerates its structure rating every combat turn.  This means that the wall can be destroyed by rapid attacks fairly easily... Also, it may have trouble containing an explosion past the first bounce.

Changing the size/shape of the wall after casting

You cannot change the size or shape of the wall after casting.

You can 'recast' the spell though.

Moving the Wall.

In theory you can move the wall after casting.  This is a complex action.

Crushing people against another barrier?  This can be done, but it involves an opposed strength+body roll vs the 'strength' of the barrier, which is equal to the Force of the barrier.  Net successes equal damage to the losing roll.

Tricks you can play with Physical Barrier:

Chunky Salsa:

Mage holds an action, Street Sam throws grenade, mage cast physcial barrier (Dome shape) over the grenade and victims.  Depending on strength of barrier, it may or may not hold, but even one rebound is going to hurt...

Road Block:

Cast the barrier accross a road, first car to hit will most likely break the barrier, but will also crash and burn as well...

Ramp (or the Dukes of Hazard trick):

Cast the spell in front of a car/bike so that it can use the barrier as a ramp and jump over an obstacle (like a wall).  Drop the spell before pursuers can use the same ramp.  Spell must be strong enough to hold the car (say force 6 at least).

Bridge:

Two buildings, two far away to jump.  A strong enough physical barrier may helo get you accross

Magic Carpet:

Combine a flat wall shapped physical barrier with the levitate spell...  Carry your team and more through the city.  Just dont let your concentration slip...

[All4BigGuns]

Because your hits are capped by Force. Force 2 spell can only use 2 hits, no matter how many you roll.

Ouch.  So if you want a small, but powerful wall, you need to cast it with high Force, but then drop a large number of dice from the dicepool to reduce the size.  Sounds a bit... well not good for the caster.

Or use Arcana and a Spell Design knowledge skill to create a new barrier spell with a set size. 

[Lethe]

Chunky Salsa:

Mage holds an action, Street Sam throws grenade, mage cast physcial barrier (Dome shape) over the grenade and victims.  Depending on strength of barrier, it may or may not hold, but even one rebound is going to hurt...

Not really worth it! With 20 exploding dice you get an average of 8 hits, equaling barrier 8. That's not enough for any salsa. To create some salsa effect you need at least barrier 13. So on average, trying it a thousand times and spending a thousand edge, you succeed just once.

[Mirikon]

Chunky Salsa:

Mage holds an action, Street Sam throws grenade, mage cast physcial barrier (Dome shape) over the grenade and victims.  Depending on strength of barrier, it may or may not hold, but even one rebound is going to hurt...

Not really worth it! With 20 exploding dice you get an average of 8 hits, equaling barrier 8. That's not enough for any salsa. To create some salsa effect you need at least barrier 13. So on average, trying it a thousand times and spending a thousand edge, you succeed just once.

I agree it doesn't help with chunky salsa from damaging grenades. However, it is nice for, say, keeping in the effects of that gas grenade full of Seven-7, or the Ringu sprayer, or the Laes/DMSO Splash grenade, or... Well, you get the idea.

[Teknodragon]

Chunky Salsa:

Mage holds an action, Street Sam throws grenade, mage cast physcial barrier (Dome shape) over the grenade and victims.  Depending on strength of barrier, it may or may not hold, but even one rebound is going to hurt...

Not really worth it! With 20 exploding dice you get an average of 8 hits, equaling barrier 8. That's not enough for any salsa. To create some salsa effect you need at least barrier 13. So on average, trying it a thousand times and spending a thousand edge, you succeed just once.

I agree it doesn't help with chunky salsa from damaging grenades. However, it is nice for, say, keeping in the effects of that gas grenade full of Seven-7, or the Ringu sprayer, or the Laes/DMSO Splash grenade, or... Well, you get the idea.

Conversely, a dome over the target keeps them from throwing the grenade back, or running away from it. So while no chunky salsa, they're stuck within the blast radius unless they have a friend outside the barrier take it out in time.