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Message no. 1
From: dbuehrer@****.org (David Buehrer)
Subject: Explosions in Barriers
Date: Tue, 30 Jul 1996 10:20:19 -0600 (MDT)
If an explosion occurs inside of a circular/spherical
barrier the following will result. The mage in the center
of the barrier will get hit by two shock waves, one from
the explosion and one reflection. These two shockwaves
then meet on the other side of the mage and pass through
eachother and the mage gets hit again by two shock waves.
Want to see how it works? Take a bucket and put some water
in it (it has to be a round bucket). Drop something in the
center of the bucket and watch the wave created expand out
to the sides and bounce back in on itself meeting in the
center and then repeating until it dies out. Now drop
something between the center and the side.

Basically, as far as the shock wave is concerned, there are
only to reflective surfaces inside a sphere/circle. The
easiest way to figure out the effect of such an event is to
treat the mage as if he is standing between two walls at a
distance equal to the radius of the barrier. Place the
explosion between the mage and one of the walls at distance
from the mage equal to the distance of the actual explosion
from the mage (I'm gonna be a lawyer some day ;) Now
figure out the reflections.

-David

/^\/^\/^\/^\/^\/^\/^\/^\ dbuehrer@****.org /^\/^\/^\/^\/^\/^\/^\/^\
"His thoughts tumbled in his head, making and breaking alliances like
underpants in a dryer without Cling Free."
~~~~~~http://www.geocities.com/TimesSquare/1068/homepage.htm~~~~~~~
Message no. 2
From: "Ojaste,James [NCR]" <ojastej@******.sid.ncr.doe.ca>
Subject: RE: Explosions in Barriers
Date: Tue, 30 Jul 96 12:59:00 PDT
> If an explosion occurs inside of a circular/spherical
> barrier the following will result. The mage in the center
> of the barrier will get hit by two shock waves, one from
> the explosion and one reflection. These two shockwaves

And one from the reflection's reflection, and so on.
This is where it gets interesting.

> then meet on the other side of the mage and pass through
> eachother and the mage gets hit again by two shock waves.
> Want to see how it works? Take a bucket and put some water
> in it (it has to be a round bucket). Drop something in the
> center of the bucket and watch the wave created expand out
> to the sides and bounce back in on itself meeting in the
> center and then repeating until it dies out. Now drop
> something between the center and the side.

This is kinda like pg 98 in SRII, but not quite, as
I'll attempt to convince you of later.

> Basically, as far as the shock wave is concerned, there are
> only to reflective surfaces inside a sphere/circle. The

Actually, there is only one, and it's round. Unless
of course, you're counting inside and outside? ;-)

> easiest way to figure out the effect of such an event is to
> treat the mage as if he is standing between two walls at a
> distance equal to the radius of the barrier. Place the

So you're reducing the 2D, circular (well, planar)
geometry to a 1D, linear geometry (the SR rules already
bring it down from 3D to 2D). This means that you're
not only ignoring the blast from above and below
(according to the rules), but also from the sides.

> explosion between the mage and one of the walls at distance
> from the mage equal to the distance of the actual explosion
> from the mage (I'm gonna be a lawyer some day ;) Now
> figure out the reflections.

So in a situation like this:
_________
/1 \
/ |\ \
| | \ |
| | \ |
|2--G---MS-----3|

For the initially-impaired:
G=Grenade
S=Shrapnel
M=Mage

your legalistic [ ;-) ] logic seems to indicate that
while the poor mage (yeah, right) will get hit by shrapnel
reflecting from points 2 & 3, the shrapnel headed his
way from point #1 will miss him.

Now, if we use a mathematically-perfect model where the
grenade, shrapnel and mage are all points, then yes,
your model holds (try drawing the reflection line from
the mage back to the grenade - it'll reflect straight
back to the mage). Unfortunately for the mage, the grenade
isn't a point in space, the shrapnel aren't points in space
and the mage *definitely* isn't a point. In fact, the mage
would probably take up an ovoid (for simplicity) about
2m * 0.5m * 0.25m.

James

--
I can't be bothered to think up a generally witty comment right now, so
if you'll just leave your sense of humour at the tone...
Message no. 3
From: dbuehrer@****.org (David Buehrer)
Subject: Re: Explosions in Barriers
Date: Tue, 30 Jul 1996 11:46:37 -0600 (MDT)
Ojaste,James [NCR] wrote:
|
|So in a situation like this:
| _________
| /1 \
| / |\ \
|| | \ |
|| | \ |
||2--G---MS-----3|
|
|For the initially-impaired:
|G=Grenade
|S=Shrapnel
|M=Mage
|
|your legalistic [ ;-) ] logic seems to indicate that
|while the poor mage (yeah, right) will get hit by shrapnel
|reflecting from points 2 & 3, the shrapnel headed his
|way from point #1 will miss him.
|
|Now, if we use a mathematically-perfect model where the
|grenade, shrapnel and mage are all points, then yes,
|your model holds (try drawing the reflection line from
|the mage back to the grenade - it'll reflect straight
|back to the mage). Unfortunately for the mage, the grenade
|isn't a point in space, the shrapnel aren't points in space
|and the mage *definitely* isn't a point. In fact, the mage
|would probably take up an ovoid (for simplicity) about
|2m * 0.5m * 0.25m.

Well if you want to get picky :) (I was just trying to
satisfy my geasa ;)

I suppose to the easy way to deal with such a situation is
to just tell the player that his character is dead. On the
plus side the barrier goes down (cuz he's dead) and his
friends can sponge him up and burry him.

Quick question. If you waste a mage with a quickened barrier, does the
barrier go down? An anchored barrier?

-David

/^\/^\/^\/^\/^\/^\/^\/^\ dbuehrer@****.org /^\/^\/^\/^\/^\/^\/^\/^\
"His thoughts tumbled in his head, making and breaking alliances like
underpants in a dryer without Cling Free."
~~~~~~http://www.geocities.com/TimesSquare/1068/homepage.htm~~~~~~~
Message no. 4
From: William Monroe Ashe <wma6617@*******.tamu.edu>
Subject: Re: Explosions in Barriers
Date: Tue, 30 Jul 1996 15:22:35 -0500 (CDT)
On Tue, 30 Jul 1996, David Buehrer wrote:

> from the mage (I'm gonna be a lawyer some day ;) Now
> figure out the reflections.
>
Actually this is a classic optics problem. If you were to consult any
advanced optics text you would see this. For reference consider a planar
Fabry Perot etalon with perfectly reflecting mirrors.

Anyway; if you allow that all of the energy is relected you will have an
INFINITE number of reflections. Provided you do not include a mechanism
for removing energy from the shock waves.

See Ma I learned something in college.

for once I can comment about something I know about.

regards
Bill
Message no. 5
From: "Ferri Pagano" <Ferri_Pagano_at_STRM__Amsterdam1@******.com>
Subject: Re: Explosions in Barriers
Date: Tue, 30 Jul 96 20:42:56 EST
David wrote....

If an explosion occurs inside of a circular/spherical
barrier the following will result. The mage in the center
of the barrier will get hit by two shock waves, one from
the explosion and one reflection. These two shockwaves
then meet on the other side of the mage and pass through
eachother and the mage gets hit again by two shock waves.
Want to see how it works? Take a bucket and put some water
in it (it has to be a round bucket). Drop something in the
center of the bucket and watch the wave created expand out
to the sides and bounce back in on itself meeting in the
center and then repeating until it dies out. Now drop
something between the center and the side.

Basically, as far as the shock wave is concerned, there are
only to reflective surfaces inside a sphere/circle. The
easiest way to figure out the effect of such an event is to
treat the mage as if he is standing between two walls at a
distance equal to the radius of the barrier. Place the
explosion between the mage and one of the walls at distance
from the mage equal to the distance of the actual explosion
from the mage (I'm gonna be a lawyer some day ;) Now
figure out the reflections.

-David

-------------------------

Hmm true, darn you'd think after 2 years of physics I'd figure these
things out myself...I think I'll ask my money back from the UVA.....

Then again, never mind. If I have to start to calculate paths for shockwaves
depending on outer shapes...specially irregular ones... no thx.
Basically chunky salsaÞath=guacamole = mage to YUCK! spell.
F.
Message no. 6
From: "Sascha Pabst" <Sascha.Pabst@**********.Uni-Oldenburg.DE>
Subject: Re: Explosions in Barriers
Date: Wed, 31 Jul 1996 14:35:56 +0000
Around 30 Jul 96 at 10:20, some people wrote approx (I took David Buehrer's
quote as example):
> If an explosion occurs inside of a circular/spherical
> barrier the following will result. The mage in the center
> of the barrier will get hit by two shock waves, one from
> the explosion and one reflection.
So the afore mentioned _bullet_ barrier will suddenly live through its own
awakening and start being impenetrable by air, too? Right after letting
through the grenade?
Several people argumented along these lines, but I for one cruel GM have yet
to see the Bullet Barrier that stops shock waves, sorry.

Sascha
--
+---___---------+----------------------------------------+--------------------+
| / / _______ | Jhary-a-Conel aka Sascha Pabst |The one who does not|
| / /_/ ____/ |Sascha.Pabst@**********.Uni-Oldenburg.de| learn from history |
| \___ __/ | | is bound to live |
|==== \_/ ======| *Wearing hats is just a way of life* | through it again. |
|LOGOUT FASCISM!| - Me | |
+------------- http://www.informatik.uni-oldenburg.de/~jhary -----------------+
Message no. 7
From: rhoded01@******.STCLOUD.MSUS.EDU (Ahzmandius)
Subject: Re: Explosions in Barriers
Date: Wed, 31 Jul 1996 08:12:57 -0600 (CST)
> Hmm true, darn you'd think after 2 years of physics I'd figure these
>things out myself...I think I'll ask my money back from the UVA.....
>
>Then again, never mind. If I have to start to calculate paths for shockwaves
>depending on outer shapes...specially irregular ones... no thx.
>Basically chunky salsaÞath=guacamole = mage to YUCK! spell.
> F.
>
Is a panther round a bullet?

Ahz
>
Message no. 8
From: dbuehrer@****.org (David Buehrer)
Subject: Re: Explosions in Barriers
Date: Wed, 31 Jul 1996 07:13:38 -0600 (MDT)
Sascha Pabst wrote:
|
|Around 30 Jul 96 at 10:20, some people wrote approx (I took David Buehrer's
|quote as example):
|> If an explosion occurs inside of a circular/spherical
|> barrier the following will result. The mage in the center
|> of the barrier will get hit by two shock waves, one from
|> the explosion and one reflection.
|So the afore mentioned _bullet_ barrier will suddenly live through its own
|awakening and start being impenetrable by air, too? Right after letting
|through the grenade?
|Several people argumented along these lines, but I for one cruel GM have yet
|to see the Bullet Barrier that stops shock waves, sorry.

Gee, thanks for using *my* name ;) My post was an arguement
of what would happen if the barrier *did* reflect a shock
wave from the inside.

Here's an interesting problem. Let's say a PC's favorite
spell is mana ball. An NPC does a little research and finds
this out. When the NPC gets into combat with the PC the
NPC puts a mana barrier around the PC. If the PC now casts
a mana ball will it reflect off the mana barrier the same
way a physical shock wave would reflect off a physical
barrier?

-David

/^\/^\/^\/^\/^\/^\/^\/^\ dbuehrer@****.org /^\/^\/^\/^\/^\/^\/^\/^\
"His thoughts tumbled in his head, making and breaking alliances like
underpants in a dryer without Cling Free."
~~~~~~http://www.geocities.com/TimesSquare/1068/homepage.htm~~~~~~~
Message no. 9
From: "Ferri Pagano" <Ferri_Pagano_at_STRM__Amsterdam1@******.com>
Subject: Re[2]: Explosions in Barriers
Date: Wed, 31 Jul 96 16:03:21 EST
Ahz wrote...
>
Is a panther round a bullet?
------------------------------------
Yep. So is a rotary cannon round. It is an explosive bullet.
Anything much larger than a panther though and you start getting into the realms
of shells & real cannons.
F.
Message no. 10
From: "Sascha Pabst" <Sascha.Pabst@**********.Uni-Oldenburg.DE>
Subject: Re: Explosions in Barriers
Date: Wed, 31 Jul 1996 18:01:13 +0000
On 31 Jul 96 at 7:13, David Buehrer wrote:
> Sascha Pabst wrote:
> |Around 30 Jul 96 at 10:20, some people wrote approx (I took David Buehrer's
> |quote as example):
[snip]
> Gee, thanks for using *my* name ;) My post was an arguement
> of what would happen if the barrier *did* reflect a shock
> wave from the inside.
Sorry, but yours was the message up when I decided against better knowing I'd
participate in this argument :-) And maybe I have just overseen that
hypothetical "if-did" you mentioned... hm.

[Mana[ball|bolt|whatever] against Mana Barrier]
> If the PC now casts
> a mana ball will it reflect off the mana barrier the same
> way a physical shock wave would reflect off a physical
> barrier?
I don't think so.
a) The spell needs LOS to "align the auras" (whatever _that_ does mean, the
caster is probably not astrally perceiving while casting), and through this
need for "alignment" (I think a bunch of hermetic mages did come up with these
stupid terms! :-) I'd doubt the spell could hit anything other then the
target. (Although it _might_ be a GM call if the "new target" is within LOS
of the caster, too... like the caster's buddy in front of him).
b) In astral space, the spell and the barrier are fighting against each other.
If the spell wins, it breaks through (maybe weaker then before, but it breaks
through). If the barrier wins, the spell "dies" (I think this is stated in
SRII or Grimoire, but both books are at a friend, so I can`t check right now).
"Dying" would mean "is reduced to force 0", and that prevents quite
effectively the "bouncing" :-)

Sascha
--
+---___---------+----------------------------------------+--------------------+
| / / _______ | Jhary-a-Conel aka Sascha Pabst |The one who does not|
| / /_/ ____/ |Sascha.Pabst@**********.Uni-Oldenburg.de| learn from history |
| \___ __/ | | is bound to live |
|==== \_/ ======| *Wearing hats is just a way of life* | through it again. |
|LOGOUT FASCISM!| - Me | |
+------------- http://www.informatik.uni-oldenburg.de/~jhary -----------------+
Message no. 11
From: dbuehrer@****.org (David Buehrer)
Subject: Re: Explosions in Barriers
Date: Wed, 31 Jul 1996 11:43:08 -0600 (MDT)
Sascha Pabst wrote:

|I wrote:
|
|> Sascha Pabst wrote:
> |Around 30 Jul 96 at 10:20, some people wrote approx (I took David Buehrer's
> |quote as example):
[snip]
|> Gee, thanks for using *my* name ;) My post was an arguement
|> of what would happen if the barrier *did* reflect a shock
|> wave from the inside.

|Sorry, but yours was the message up when I decided against better
|knowing I'd participate in this argument :-) And maybe I have just
|overseen that hypothetical "if-did" you mentioned... hm.

I might have been a little vague. ah well.

|> If the PC now casts
|> a mana ball will it reflect off the mana barrier the same
|> way a physical shock wave would reflect off a physical
|> barrier?

|I don't think so.
|a) The spell needs LOS to "align the auras" (whatever _that_ does mean,
|the caster is probably not astrally perceiving while casting), and
|through this need for "alignment" (I think a bunch of hermetic mages
|did come up with these stupid terms! :-) I'd doubt the spell could hit
|anything other then the target. (Although it _might_ be a GM call if
|the "new target" is within LOS of the caster, too... like the caster's
|buddy in front of him). b) In astral space, the spell and the barrier
|are fighting against each other. If the spell wins, it breaks through
|(maybe weaker then before, but it breaks through). If the barrier wins,
|the spell "dies" (I think this is stated in SRII or Grimoire, but both
|books are at a friend, so I can`t check right now). "Dying" would mean
|"is reduced to force 0", and that prevents quite effectively the
|"bouncing" :-)

Bummer. It would have been so cool. Maybe I'll try to design a spell
barrier that reflects spells instead of killing them.

-David

/^\/^\/^\/^\/^\/^\/^\/^\ dbuehrer@****.org /^\/^\/^\/^\/^\/^\/^\/^\
"His thoughts tumbled in his head, making and breaking alliances like
underpants in a dryer without Cling Free."
~~~~~~http://www.geocities.com/TimesSquare/1068/homepage.htm~~~~~~~
Message no. 12
From: "Gurth" <gurth@******.nl>
Subject: Re: Re[2]: Explosions in Barriers
Date: Thu, 1 Aug 1996 11:39:15 +0100
Ferri Pagano said on 16:03/31 Jul 96...

> Ahz wrote...
> >
> Is a panther round a bullet?
> ------------------------------------
> Yep. So is a rotary cannon round. It is an explosive bullet.
> Anything much larger than a panther though and you start getting into the realms
> of shells & real cannons.

Although I stand by my comment that a Bullet Barrier spell sees any
bullet as "a bullet" and stops it in the same way. Since a Panther cannon
shell (or a round from a Stonewall MBT, for that matter) is a
high-velocity projectile, I'd say the Bullet Barrier defends against them
as well.

--
Gurth@******.nl - http://www.xs4all.nl/~gurth/index.html
I've been searching most my life for anything to believe in,
like God or love or something -- any kind of simple solution.
-> NERPS Project Leader & Unofficial Shadowrun Guru <-
-> The Character Mortuary: http://huizen.dds.nl/~mortuary/mortuary.html <-

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