Chunky salsa rule flaw, it just hit me Options

[IKerensky]

After all that discussion about grenades and thus something hit me.

Grenade rules add damage because the blast reverberate on wall back to explosion origine. If room is small enough the blast could reverberate multiple time causing very high damage.

Then I realise that the shockwave cant reverberate more than once on the wall, because the instant he reach back origin point it meet with another shockwave incoming from the exact opposite direction with the exact same strenght and CANCEL each other. Of course, for ease I am considering a square room with explosion origin being the center of the square.

Think it is time to errata the thing to limit reverberation to only one time.

[Yerameyahu]

Assume a spherical cow, all the complexity is gone! :/

[Jeremiah Kraye]

You know... you could assume that if you stuck a person, in an elevator with a grenade... they deserve to die... Just saying.

I mean as a future DM if my players ever put an NPC in that position that isn't a freaking robot, I'm just gonna explain the fine-mist shooting through the closed doors.

If it's a robot I'll explain the inevitable sound of the elevator dropping X stories screeching all the way down, and thunk... *dust cloud*

Also just an FYI but nuclear weapons used focused explosives to compact raw nuclear material to start the reaction. These specially crafted explosive charges are build to direct their force inward, they don't "negate each other". In an elevator the force would direct outward from the device, attempting to escape the space, be limited by the lack of available space and compact and destroy what is within the space. The force and damage per area of a contained explosion is usually bigger than one that isn't.

[Dakka Dakka]

You may want to read up on interference. Whether they cancel each other out depends on the wavelength and the difference in traveled distance of the "two" waves. Also the shock wave possibly only has one crest. Reflecting that crest will not cause interference.

[Daddy's Litt...]

"chunky salsa just hit me" I'll get a mop. (IMG:style_emoticons/default/spin.gif)
There is one small problem with your theory though, beyond what others have said aboput frequency- think of that pressure as two trucks speeding towards each other. Sure they will stop and lose all their kenetic energy when they hit each other, but what is caught between them will absorb ALL of the energy.

[Irion]

But, it they should not drive back and hit that poor thing again...

[Jeremiah Kraye]

Yep, the objects retain force, when they strike each other they transfer their force (which is running opposite to each other) violently into the opposing object. Those objects are compressed by the opposing forces, thus the crumpled can effect when a car slams into another. Remaining force is actually radiated out from the collision point, thus expressed by interference, and the radial pattern you see when waves of water collide and express the remaining force outward from the collision point.

[CanRay]

Now I remember why I failed physics. My brain hurts now.

[Yerameyahu]

But, it they should not drive back and hit that poor thing again...

Actually, they should… if they're air molecules (just for example). They hit each other, and bounce off again. Pressure waves are different, and just pass *through* each other, I thought. You don't get cancellation like OP mentions unless they're opposite, and they wouldn't be.

[Jeremiah Kraye]

There's a good example of how force is transferred, a prime example are custom made "wax slug shells" that are being tested by a group. Basically fill a standard shotgun shell with wax to bind the smell pellets together. When the "wax slug" is fired initially it will travel the distance to the target, strike, enter the target then the friction will begin to apply splitting the shell into its component pellets. What you get is an absolute mess as each pellet transfers more resulting force into the flesh. Essentially the equivalent of shooting a standard shotgun shell point blank with a target without having to be point blank.

There is another version of this for high powered rifles that breaks up upon entry into a wall... splatters whatever is behind it in super-hot shrapnel.

[Aerospider]

The biggest flaw in the physics of the chunky salsa rule is that the resounding force loses no strength from its impact with the wall. Just the kind of perfect elasticity to have Newton spinning in his grave (entropically of course).

[Yerameyahu]

Yeah, but it's complicated enough already. If you wanted to, you could could hitting barriers themselves as an extra 1m of distance, for example. Honestly, it doesn't make the chunky salsa rule any better to do so, and the crazy edge cases are still pretty crazy.

[CanRay]

OK, better explosives rules. Gotcha.

[Yerameyahu]

I kinda liked the idea that someone half-suggested in the other thread: just give a flat bonus/multiplier for coarse situations like 'small fully-enclosed space' (DV+6, DV*3, I dunno), 'half-enclosed' (DV+3, DV*1.5), etc. You'd have to play around and see if it works at all, but it would at least be fast and simple (half the battle).

The other three-halves of the battle is making grenade/rocket rules *match* demolition/explosives rules in power, effects, and price.

[Bazhel]

heh... if you want to complicate things further.... When an explosion occurs, especially in an enclosed area all that oxygen is burnt off creating a temporary vacum, now was the players in a hermeticly sealed vault did you say??
In an open area it actually means you get slapped twice... once by the shockwave of the explosion and once by the inrushing air....

[Yerameyahu]

That'd be a hell on an explosion. Not a hand grenade, but sure. (IMG:style_emoticons/default/smile.gif)

[pbangarth]

In the situation expressed in the OP, in which the subject is exactly in the middle in order for the returning shock waves to meet at the subject, the returning shock waves would add to each other, not cancel.

[Nath]

Also just an FYI but nuclear weapons used focused explosives to compact raw nuclear material to start the reaction. These specially crafted explosive charges are build to direct their force inward, they don't "negate each other".

In implosion-type nuclear weapons, the triggering explosions never get the chance to meet each other. Fat Man (the Nagasaki bomb) had 32 outer explosive charges that hit a second layer of explosives that hit a third layer of explosives that hit a layer of aluminium that pushes a layer of beryllium-polonium and a layer of plutonium, with a now near-perfect inward spheric shockwave. The plutonium is crushed to reach critical mass while the compressed beryllium-polonium layer release a burst of neutrons to ignite the nuclear fission. At that point, what remains of the triggering explosions can abandon all hope of ever meeting each other one day because there now is a nuclear explosion starting between them.

[Yerameyahu]

Exactly, pbangarth, but after adding at the exact middle, they'd continue 'through' each other, wouldn't they?

[Falconer]

Actually the rules only deal with explosions in confined spaces... I'm not certain simply setting a grenade off by the ground or next to a wall is supposed to cause chunky salsa.

As soon as any hole in the enclosure is created the thing is supposed to stop bouncing and spread out normally.

Though I guess... it depends... an elevator even with the door open is still pretty confined...




Also, high explosives don't burn off the oxygen, they include their own oxidizer... (they'll even go off in a vacuum). Some fuel air explosives will burn off the oxygen in an area... but even that is more of a problem in enclosed spaces.

[Yerameyahu]

Well, the blast first checks the barrier; if the barrier breaks, there's no reflection (and in fact causes shrapnel in the outward direction).

Yeah, if you start saying 'the ground or a wall isn't okay', you have to decide where the line is… and why. (IMG:style_emoticons/default/smile.gif) The 'why' is going to tell you that everything reflects (if it can), so that's out. But then you've got some nutty results to contend with, even *without* thinking about multiple passes of reflection: a grenade in the corner of a strong room is now doing a 800% blast (at least, it's spread over 1/8th of the sphere)? Or is it 400% (which is still horrific)? Get out your protractor and prepare for TPK (or, easy defeat of that big bad you wasted time writing a backstory for).

[Draco18s]

The biggest flaw in the physics of the chunky salsa rule is that the resounding force loses no strength from its impact with the wall. Just the kind of perfect elasticity to have Newton spinning in his grave (entropically of course).

You forgot the linear vs. quadratic falloff issue.

[Falconer]

Guess you could always just consider it volumetically... if a normal grenade covers 300 cubic meters... and the blast is confined in a 100cubic meter space... triple the damage.

Still doesn't deal well with something like a dead end hallway though... except for channeling the blast out and into the PC's (evil GM laugh)...

[pbangarth]

Exactly, pbangarth, but after adding at the exact middle, they'd continue 'through' each other, wouldn't they?

Yes, they would, just as waves in water. As was mentioned above, too, there would be some inelastic absorption in the walls, even if they held and didn't buckle, and the distance to power curve is not linear. But shit, who wants to do that kind of calculation?

[CanRay]

Why did I have to give my physics textbook to my old GM as a RPG aid and not get it back before I moved?