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Thot

Firearms, joules and damage dice

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9 hours ago, Atgxtg said:

The thing about "damage" is that is isn't the same thing as energy. A weapon can have a lot of energy than another but end up doing less damage to a human body fr several reasons. 

...snip

This. In fact this many times over. A Spitzer is going to have greater range and penetration, but is going to probably transfer less energy to its target when compared to a round nose or a ball. 

I think Sandy tried to use a muzzle energy calculation when trying to figure firearms damage for Cthulhu Now. He mentioned using Janes as a source and ending up with some really odd results, so he fudged. I'm not sure if he just ended up eyeballing it, or using his calculations as a basis and then moving things up or down.

SDLeary

Edited by SDLeary

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5 hours ago, Thot said:

The problem is that most weapons in the BGB table cannot be easily identified (or at all) with any certainty. So we could probably both find weapons that fit or don't fit with the formula, but you are right that the formula fails for the really small guns like a Derringer or other .38 calibre weapons.

 

You could find a copy of Delta Green (the old one), or The Weapons Compendium (by John Crowe III, Pagan Publishing 1995), upon which the DG data is based on. In DG, they have a large listing of firearms, mostly "modern", but they also break down things to individual rounds. They also provide info for D20, so you can use sources for that an back engineer if you want to. 

Just for reference though, I do think that firearms damage is too high, in general, especially for pistols.

SDLeary

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6 hours ago, Atgxtg said:

Actually they can. Pretty much all of the weapons in the BGB table came from other Chaosium RPGs,, Pretty much all of the firearm stats came from Call of Cthulhu. Jason "filed off" the names, gave them generic names such as "medium pistol". but it's easy enough to backtrack it. In a few instances he adjusted a weapon a little for some reason or another, but they are still the weapons from CoC.  Some examples:

BGB Light Pistol  is a CoC .22 Short Automatic

BGB Heavy Pistol is a CoC .45 Automatic

BGB Assault rifle is a CoC AK-47 (with an extra point of damage)

BGB Bolt Action Rifle is a CoC .30-06 Bolt Action Rifle

 

You can go through the weapon tables in both RPGs and see which weapon is which.

Interesting. Thanks!

.22 Short is 110-120 Joules, which is below the range the present formula can cover. Damage is given 1D6 or 3.5 average.

.45 Automatic is 500 to 835 Joules, depending on exact cartridge. Damage is given as 1D10+2, or 7.5 average.

AK-47 is 7.62×39mm, 2000 to 2200 Joules. Damage is given ans 2D6+2.

.30-06 is 3800 to 4000 Joules. Damage is given as 2D6+4.

 

I'll make a more complete spreadsheet, fiddle with the numbers a bit more and report back. :)

 

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I don't mean to be a pain, just want to make sure what we got works. I've gone down the same round that you have. I've even tried to see if I could find a correction between BGB/CoC damage and BRTC's 3G3 or EABA. If I recall correctly using force (mv) rather than energy (1/2mv^2) gave a somewhat better fit.

When they did the modern tech supplement (I forgot the name) a few years back they folks who did so did use a lograrthic energy progression, but they also differentiated between damage and penetration. And it was more of an all or nothing thing, as anything that did penetrate body armor usually had enough energy left over to still inflict a serious wound. 

Here are some common energy values for handgun rounds: https://en.wikipedia.org/wiki/Muzzle_energy

 

 

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10 hours ago, SDLeary said:

You could find a copy of Delta Green (the old one), or The Weapons Compendium (by John Crowe III, Pagan Publishing 1995), upon which the DG data is based on. In DG, they have a large listing of firearms, mostly "modern", but they also break down things to individual rounds. They also provide info for D20, so you can use sources for that an back engineer if you want to. 

Just for reference though, I do think that firearms damage is too high, in general, especially for pistols.

SDLeary

I agree. I think the problem is due to the way damage works in BRP. One the one hand every round should have to potential to kill someone, so you can't really go below 1D6 or so. On the other hand, damage that doesn't disable a hit location or cause a major wound doesn't have any stopping power in game terms. So the damage gets pumped up to keep a single shot from a firearm a legitimate threat. 

 

I also thing the big adds that some weapons get (i.e. 2D6+4) are bad, since they make it impossible for someone to ever just get "grazed" by those rounds.  2D6+4 is a minimum of 6 points, which will probably take out a location or cause a major wound. So Rifles become much more effective than in real life. Frankly, had the gone with 3D6+1 or 2D10 instead of 2D6+4, the results would probably have been better as far as people damage went. But that would have caused some problems with the way armor works. 

 

Maybe a better approach would have been to lower the firearm damages but give them better specials (like the rapiers triple damage). That way most weapons could inflict less damage on a minor hit, but be much more lethal with a well placed shot. 

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3 hours ago, Atgxtg said:

IMaybe a better approach would have been to lower the firearm damages but give them better specials (like the rapiers triple damage). That way most weapons could inflict less damage on a minor hit, but be much more lethal with a well placed shot. 

I've always liked the GURPS approach where all weapons (not just firearms) can potentially do x1.5 (cutting, "large piercing") or x2 damage ("impaling") if they penetrate armor.  Bullets, in particular, can get pretty nasty if they connect, but can just as easily glance off body armor.  (There's also rules for armor-piercing rounds.  And damage to non-living entities.  There's rules for everything.)  Shotguns, BTW, do "small piercing" damage, which means that any damage that gets through armor is cut by half, I guess because buckshot shreds armor but doesn't penetrate too far.

On the other hand, looking at GURPS Lite (4e), most guns do Nd6 +/- 0..2, "piercing" damage (i.e. unmodified). A .357 Revolver, for example, does "3d[6]-1", for a range of 2..17.  A ".30 Lever-Action Carbine" from TL 5 (e.g. a Winchester, I guess) does "5d[6]", or 5..30, average 17.5.  A modern .338 Sniper Rifle does "9d[6]+1", or 10..55, average of 28.5 ... if it connects, it'll probably kill you, no matter how much you can bench press.  My impression is that a lot of gun bunnies had input on GURPS (Texas, y'all), so the damages are probably not that unrealistic.  So a "graze" or "flesh wound", as convenient as it is dramatically, is pretty damn unlikely, in GURPS at least.

Short of going full Shot Clock (from Kenzer's Aces & Eights) the best approach, if you want to make guns scary but not auto-kill, might be a combination of range and aiming penalties and maybe a "damage cap" to represent "through and through" wounds that avoid hit locations with major organs.  (Though there's still arterial bleeds ...)  Or just embrace cinematic convention a la FATE or Cypher and assume guns do comparable damage to swords and arrows.

Side note: a guy I knew once playtested a "realistic" FBI RPG.  Oh, it was realistic: if you didn't follow standard police procedures, i.e. maximum paranoia, a bullet would take you out for the rest of the scenario.

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Some of the systems that I really liked, in terms of firearm damage were the James Bond RPG, Timelords, and CORPS (Greg Porter usually does a good job with firearm rules ). 

What I liked about them was that guns (and most other weapons) could do minor damage on a marginal hit, but became much more deadly with a well placed shot. But those systems also had a would shock mechanic of some sort where somebody who just got injured could be temporarily stunned for a few game turns. It was nice because getting shot (or stabbed, sliced or bludgeoned) can often take the fight out of someone without actually killing them or rendering them unconscious. In real life most gunshot wounds are not fatal, but most will probably "stop" somebody for a bit. 

 

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7 hours ago, Atgxtg said:

I don't mean to be a pain, just want to make sure what we got works

Don't worry, rigorous critique is the best way to improve.

7 hours ago, Atgxtg said:

 

. I've gone down the same round that you have. I've even tried to see if I could find a correction between BGB/CoC damage and BRTC's 3G3 or EABA. If I recall correctly using force (mv) rather than energy (1/2mv^2) gave a somewhat better fit.

Force is ma, not mv. ;)

But in the end, the two are equivalent. You have to find some way of translating either to damage, and while those equations will look different, in the end they will be equivalent, too (in a sense).

7 hours ago, Atgxtg said:

When they did the modern tech supplement (I forgot the name) a few years back they folks who did so did use a lograrthic energy progression, but they also differentiated between damage and penetration. And it was more of an all or nothing thing, as anything that did penetrate body armor usually had enough energy left over to still inflict a serious wound. 

Here are some common energy values for handgun rounds: https://en.wikipedia.org/wiki/Muzzle_energy

Well, I am collecting the data for various rounds from all around the net, but Wikipedia is a very encompassing source, yes. You can get more detailed info from each individual cartridge's wiki page, though, which sometimes includes measured steel penetration.

I am not at all done with the spreadsheet, but the fact that a Derringer's .41 Short round has a muzzle energy of a mere 71 Joules is worth mentioning. For comparison: A punch with a fist will reportedly be around 100  Joules for a normal human... granted, that energy is but into effect on a much larger surface, so penetration will not be as deep, but the Derringer seems to have been a particularly unimpressive weapon, unless you hit the eye. I mean, seriously, use a knife instead!

 

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So, here is a list of the weapons I have looked up and damage as computed per the old formula and as per a new one, which reads:

=MAX(((LOG(Joules;1,225))-26);1).

Name Dmg J Avrg Dam J/AvrgDmg Old formula New Formula
             
5.56×45mm NATO (e.g. G36, SA80, FAMAS, M16, AR15) 2D6 1.796 11,0 163,3 8,4 10,9
7.62×51mm_NATO (e.g. G3, L1A1 SLR, M17, M14) 2D6+4 3.506 11,0 318,7 11,7 14,2
9×19mm_Parabellum (e.g. Walther P1, Uzi, HK MP7) 1D8 678 4,5 150,7 3,6 6,1
7.62×39mm (e.g. AK-47) 2D6+2 2.179 9,0 242,1 9,4 11,9
Pistol, Derringer (.41 Short) 1D6 71 3,5 20,3 -7,5 1,0
Pistol, Flintlock 1D6+1 434 4,5 96,5 1,4 3,9
.45 ACP 1D10+2 835 7,5 111,3 4,6 7,1
.38 Short Colt (light pistols and revolvers) 1D6 245 3,5 70,0 -1,4 1,1
Revolver, Heavy (.50 Action Express) 1D10+2 2.200 7,5 293,3 9,4 11,9
Rifle, Bolt-action (7.62×63mm) 2D6+4 4.042 11,0 367,5 12,4 14,9
Rifle, Elephant (130g, 430 m/s) 3D6+4 12.019 15,5 775,4 17,8 20,3
1861 Springfield Rifle-Musket, 33 gram bullet, 290 m/s v 1D10+4 1.367 9,5 143,9 7,1 9,6
Rifle, Sniper (12.7×99mm NATO) 2D10+4 20.195 15,0 1.346,3 20,3 22,8
Rheinmetall Rh 202 (Damage derived from new formula) 5D10+2 81.070 29,5 2.748,1 27,2 29,7
Bofors 40 mm L/70 (Damage derived from new formula) 7D10 461.492 38,5 11.986,8 35,7 38,3
76mm Bofors naval ship gun (Damage derived from new formula) 7D12+1 2.637.259 46,5 526,6 44,3 46,9
120 mm Tank Gun 15D6 13.000.000 52,5 3.505,4 52,2 54,7

 

Looks fine for me. The lighter weapons come out way smaller, but then again, they should be.

Edited by Thot
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On 11/7/2016 at 4:23 AM, Atgxtg said:

Maybe a better approach would have been to lower the firearm damages but give them better specials (like the rapiers triple damage). That way most weapons could inflict less damage on a minor hit, but be much more lethal with a well placed shot. 

I'm not sure better specials are needed though, at least if damage is properly scaled. 

If we reduce a .22/Light Pistol to, say, 1d4, then an impale is still 2d4, or a critical 8 points. Assuming normal hit points, a critical with this weapon would still be a major wound for all up to HP 16. Probably a better starting point, though it does eliminate insta-kills for lower powered weaponry.* 

And the other thing to remember is that current weapon damage was formulated with normal hit points. "Heroic" hit points actually makes things possibly slightly underpowered, though I haven't looked too closely into that. 

SDLeary

*insta-kills don't exist outside of headshots (and even that is debatable) and very very rare hits directly to the heart. EVERYTHING else is bleed out of varying speed... IMHO. 

Edited by SDLeary

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1 hour ago, SDLeary said:

I'm not sure better specials are needed though, at least if damage is properly scaled. 

If we reduce a .22/Light Pistol to, say, 1d4, then an impale is still 2d4, or a critical 8 points. Assuming normal hit points, a critical with this weapon would still be a major wound for all up to HP 16. Probably a better starting point, though it does eliminate insta-kills for lower powered weaponry.* 

And the other thing to remember is that current weapon damage was formulated with normal hit points. "Heroic" hit points actually makes things possibly slightly underpowered, though I haven't looked too closely into that. 

SDLeary

*insta-kills don't exist outside of headshots (and even that is debatable) and very very rare hits directly to the heart. EVERYTHING else is bleed out of varying speed... IMHO. 

Heroic hit points are designed to have heroes standing up in a hail of bullets while blazing away and mowing down dozens of bad guys. It works when the bad guys also have very un-heroic hit points.

Firearms already have the advantages that they can't be dodged and armour is ineffective against them.

There aren't really 'bleed out' rules in BRP except for the slashing weapons special.

I guess this thread is expressing dissatisfaction with the current firearm rules?

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6 hours ago, Questbird said:

There aren't really 'bleed out' rules in BRP except for the slashing weapons special.

A bleeding rule is easily added, though.

6 hours ago, Questbird said:

I guess this thread is expressing dissatisfaction with the current firearm rules?

 

Well, at least it seems agreed that there is room for improvement.

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6 hours ago, Questbird said:

Heroic hit points are designed to have heroes standing up in a hail of bullets while blazing away and mowing down dozens of bad guys. It works when the bad guys also have very un-heroic hit points.

True, but some use it as the default. I have actually heard (rarely but it has happened) that firearms aren't powerful enough.

6 hours ago, Questbird said:

There aren't really 'bleed out' rules in BRP except for the slashing weapons special.

Which can be changed or adapted. Back in the RQIII days, we did have bleeding on any Special with any bladed weapon. The assumption being that an artery was hit. 

6 hours ago, Questbird said:

I guess this thread is expressing dissatisfaction with the current firearm rules?

A little perhaps. Really just participating in the discussion. There is always room for improvement, and bouncing ideas off of each other is a fine way to formulate a house rule. 

SDLeary

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On 11/7/2016 at 2:51 PM, Thot said:

Don't worry, rigorous critique is the best way to improve.

Force is ma, not mv. ;)

But in the end, the two are equivalent. You have to find some way of translating either to damage, and while those equations will look different, in the end they will be equivalent, too (in a sense).

Yes. mv is actually momentum. My bad. I'll blame in on the fact that someone in another thread is basing damage on the Taylor Knock-Out formula, and that is based on momentum. Ideally, since the goal is for the bullet to stop in the body of the target mv will be equal to ma. Ideally. Over penetration can be a problem with some rounds. In the end they won't really be all that equivalent. Basically, a lighter, faster round can end up with more energy that a heavier, slower round, but the slower round could have more force, make a bigger wound, and do more damage.

Quote

Well, I am collecting the data for various rounds from all around the net, but Wikipedia is a very encompassing source, yes. You can get more detailed info from each individual cartridge's wiki page, though, which sometimes includes measured steel penetration.

Yeah, but what you really want is to use average or typical rounds to get the baseline damages for the weapons. That's why I linked to the Wikipedia page. 

Quote

I am not at all done with the spreadsheet, but the fact that a Derringer's .41 Short round has a muzzle energy of a mere 71 Joules is worth mentioning. For comparison: A punch with a fist will reportedly be around 100  Joules for a normal human... granted, that energy is but into effect on a much larger surface, so penetration will not be as deep, but the Derringer seems to have been a particularly unimpressive weapon, unless you hit the eye. I mean, seriously, use a knife instead!

 

That's pretty much true for all light handguns. Basically, these days, most gun "experts" don't recommend anything less powerful than, say a 38 Special for self defense. And most would only do that for a backup weapon. Hold Out weapons are really intended to be used as a last resort at extremely close range (like pressed up against the target). It's probably more useful for it's the threat value. That it was a two shot pistol probably helped.

But that sorta hold true for other bullets. Police are taught that someone wielding a knife, shot at 20 feet distance, can still close the distance and stab the officer.  

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15 hours ago, SDLeary said:

I'm not sure better specials are needed though, at least if damage is properly scaled. 

If we reduce a .22/Light Pistol to, say, 1d4, then an impale is still 2d4, or a critical 8 points. Assuming normal hit points, a critical with this weapon would still be a major wound for all up to HP 16. Probably a better starting point, though it does eliminate insta-kills for lower powered weaponry.* 

But anything other than a critical becomes a scratch. Especially if the target has any sort of armor at all. And I don't think a dagger should be doing that much more damage. But ,to be fair to you, 1D3 with triple on an impale isn't all that different. Better, IMO, but only by a point or so. 

15 hours ago, SDLeary said:

And the other thing to remember is that current weapon damage was formulated with normal hit points. "Heroic" hit points actually makes things possibly slightly underpowered, though I haven't looked too closely into that. 

SDLeary

*insta-kills don't exist outside of headshots (and even that is debatable) and very very rare hits directly to the heart. EVERYTHING else is bleed out of varying speed... IMHO. 

Yes, very few instant-kills. But people can bleed out in under a round or two, or go into premature shock. The immediate reaction to to being shot is mostly psychological. 

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14 hours ago, Questbird said:

Heroic hit points are designed to have heroes standing up in a hail of bullets while blazing away and mowing down dozens of bad guys. It works when the bad guys also have very un-heroic hit points.

And is very silly. I had a friend who wondered/wanted to play an Old West campaign, and kina hoped that they could do in in D&D. I brought up the thought of two bullet-ridden  guys having to stop in the middle of a shootout in order to reload. 

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20 hours ago, Thot said:

So, here is a list of the weapons I have looked up and damage as computed per the old formula and as per a new one, which reads:

=MAX(((LOG(Joules;1,225))-26);1).

Name Dmg J Avrg Dam J/AvrgDmg Old formula New Formula
             
5.56×45mm NATO (e.g. G36, SA80, FAMAS, M16, AR15) 2D6 1.796 11,0 163,3 8,4 10,9
7.62×51mm_NATO (e.g. G3, L1A1 SLR, M17, M14) 2D6+4 3.506 11,0 318,7 11,7 14,2
9×19mm_Parabellum (e.g. Walther P1, Uzi, HK MP7) 1D8 678 4,5 150,7 3,6 6,1
7.62×39mm (e.g. AK-47) 2D6+2 2.179 9,0 242,1 9,4 11,9
Pistol, Derringer (.41 Short) 1D6 71 3,5 20,3 -7,5 1,0
Pistol, Flintlock 1D6+1 434 4,5 96,5 1,4 3,9
.45 ACP 1D10+2 835 7,5 111,3 4,6 7,1
.38 Short Colt (light pistols and revolvers) 1D6 245 3,5 70,0 -1,4 1,1
Revolver, Heavy (.50 Action Express) 1D10+2 2.200 7,5 293,3 9,4 11,9
Rifle, Bolt-action (7.62×63mm) 2D6+4 4.042 11,0 367,5 12,4 14,9
Rifle, Elephant (130g, 430 m/s) 3D6+4 12.019 15,5 775,4 17,8 20,3
1861 Springfield Rifle-Musket, 33 gram bullet, 290 m/s v 1D10+4 1.367 9,5 143,9 7,1 9,6
Rifle, Sniper (12.7×99mm NATO) 2D10+4 20.195 15,0 1.346,3 20,3 22,8
Rheinmetall Rh 202 (Damage derived from new formula) 5D10+2 81.070 29,5 2.748,1 27,2 29,7
Bofors 40 mm L/70 (Damage derived from new formula) 7D10 461.492 38,5 11.986,8 35,7 38,3
76mm Bofors naval ship gun (Damage derived from new formula) 7D12+1 2.637.259 46,5 526,6 44,3 46,9
120 mm Tank Gun 15D6 13.000.000 52,5 3.505,4 52,2 54,7

 

Looks fine for me. The lighter weapons come out way smaller, but then again, they should be.

The damage dice for most weapons don't seem to match up with the new formula.

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19 hours ago, Thot said:

As I said, it gives slightly different, but probably more realistic values.

Except people shoot each other with the lighter weapons, not the tank guns. 1 point MAX damage for a .41 derringer is too much the other way. Even the big guns max damage is now where the old average values were.

I think the thing is that by going from average to max damage, the formula will cut down the damage severely.

d4 (ave 2.5, max 4); d6 (ave 3.5, max 6); d8 (ave 4.5, max 8); d10 (ave 5.5, max 10); 2d6(ave 7, max 12), 2d8 (ave 9, max 16) 

So if you want to go with max damage you need a somewhat faster progression than 1.225, probably something like 1.1 for the low end stuff to work. I'll try a bit of curve fitting. The trick is finding something that works for handguns, rifles, and heavy guns. IMO, I don't think it can be done with one progression. It probably requires a decreasing exponent to get a good fit for all three. But I think if we had something that worked for hand held weapons, we'd be fine.

 

One thing that's worth considering is that the damage bonus progresses as a certain rate, as does the armor values. So whatever values we wind up with, we have to be sure that the weapons are still able to penetrate the stuff they should be able to and not penetrate the stuff they shouldn't be able to. In fact, I think I have something lying around I used for tank guns. basically, linking their damage to their armor penetration. It from my infamous vehicle design notes. I got tables with lots of tank stats and used them to reverse engineer tank gun damages based on armor penetration.  

 

 

 

Edited by Atgxtg

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1 hour ago, Atgxtg said:

Except people shoot each other with the lighter weapons, not the tank guns. 1 point MAX damage

The new formula gives us average damage. Did I phrase it otherwise? If so, then that is an error. The formula in the last column is supposed to give average damage.

Or is this based on the word "MAX" in the formula? That just limits damage to the bottom, so that you cannot do less average damage than 1.
 

1 hour ago, Atgxtg said:

for a .41 derringer is too much the other way. Even the big guns max damage is now where the old average values were.

On what do you base your assessment that a gunshot that has less energy than a punch (!) should do all that much damage?

I suggest you propose your own formula (which really could be a variation of the above, just with a different base and exponent) that suits your taste more. The more thought-out options we collect here, the better.

1 hour ago, Atgxtg said:

[...] I'll try a bit of curve fitting. The trick is finding something that works for handguns, rifles, and heavy guns. IMO, I don't think it can be done with one progression. It probably requires a decreasing exponent to get a good fit for all three. But I think if we had something that worked for hand held weapons, we'd be fine.

Looking forward to to it.

 

1 hour ago, Atgxtg said:

One thing that's worth considering is that the damage bonus progresses as a certain rate, as does the armor values. So whatever values we wind up with, we have to be sure that the weapons are still able to penetrate the stuff they should be able to and not penetrate the stuff they shouldn't be able to. In fact, I think I have something lying around I used for tank guns. basically, linking their damage to their armor penetration. It from my infamous vehicle design notes. I got tables with lots of tank stats and used them to reverse engineer tank gun damages based on armor penetration.  

Vehicle design notes? Link please? :)

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4 hours ago, Thot said:

The new formula gives us average damage. Did I phrase it otherwise? If so, then that is an error. The formula in the last column is supposed to give average damage.

Or is this based on the word "MAX" in the formula? That just limits damage to the bottom, so that you cannot do less average damage than 1.
 

Sorry, my assumption based on the word MAX and your old formula elsewhere. 

4 hours ago, Thot said:

On what do you base your assessment that a gunshot that has less energy than a punch (!) should do all that much damage?

Well, typical energy range for a punch is 100-450J, which would put in better than a .41 derringer, and in the light-medium pistol range. But, my post was based onmy eroor in assuming that the table had a .41 doing 1 point max damage. 

4 hours ago, Thot said:

I suggest you propose your own formula (which really could be a variation of the above, just with a different base and exponent) that suits your taste more. The more thought-out options we collect here, the better.

I see what I can put together. Like I said, I don't think there is one formula that will fit all. But I try to to get a closer fit-at least for the low end. 

4 hours ago, Thot said:

Vehicle design notes? Link please? :)

No link per say. Although there might still be an older copy of some quick conversion rules in the download section. Way back, I started working on some rules for statting up vehicles in BRP Game terms based on real world data and physics, and some extrapolation using the SIZ table. I got a lot of data, and some guidelines to work with. Some of the stuff worked out fine, some other things still present problems, such as damage and armor, rated speed, and determining just where to set the "baseline" values for stats such as POW (as in terms of watts or joules).  I did up a progression for armor value based on thickness and material (actually several), but its' very difficult to get everything to match up exactly with the BRP stats. And  more difficult to simply some of the math the way I want to. Mostly because the SIZ table "zeros out" at -37. 

I also was working on a bestiary with someone else that also used a formulaic approach to stat up various animals (we started with dinosaurs and then realized the approach would work with other animals) based on species, the stats for similar animals, and the cube-square law.

 

But basically, I used a very similar approach to what you are doing with weapon stats. 

 

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6 hours ago, Atgxtg said:

No link per say. Although there might still be an older copy of some quick conversion rules in the download section. Way back, I started working on some rules for statting up vehicles in BRP Game terms based on real world data and physics, and some extrapolation using the SIZ table. I got a lot of data, and some guidelines to work with. Some of the stuff worked out fine, some other things still present problems, such as damage and armor, rated speed, and determining just where to set the "baseline" values for stats such as POW (as in terms of watts or joules).  I did up a progression for armor value based on thickness and material (actually several), but its' very difficult to get everything to match up exactly with the BRP stats. And  more difficult to simply some of the math the way I want to. Mostly because the SIZ table "zeros out" at -37. 

I'd love to read that - couldn't find anything in the downloads section, though. Maybe you could open a thread about it?

6 hours ago, Atgxtg said:

I also was working on a bestiary with someone else that also used a formulaic approach to stat up various animals (we started with dinosaurs and then realized the approach would work with other animals) based on species, the stats for similar animals, and the cube-square law.

Fascinating. On what real-world data did you base your conversions? I mean getting all kinds of stats for vehicles is easy, but for animals, that is a lot harder, as far as I know.

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8 hours ago, Thot said:

I'd love to read that - couldn't find anything in the downloads section, though. Maybe you could open a thread about it?

I could (and at times havve done so), but I don't think that many people are interested. I could send you some of my notes. Most of my notes are a bit rough. Some things weren't locked down and I charged a few formulas on the way. 

8 hours ago, Thot said:

Fascinating. On what real-world data did you base your conversions? I mean getting all kinds of stats for vehicles is easy, but for animals, that is a lot harder, as far as I know.

The mass of the animals. The way it worked was that you'd start off with an animal you wanted to get stats for For example, a Kodiak Bear. The you'd look for stats for a similar creature - that is another bear. Let's say a Brown Bear. Then you'd would check the differences in mass between the two, and convert both of those into SIZ stats using the SIZ table. For dinosaurs it was a little tricker, since we didn't always have a mass for a given dino, and would have to extrapolate the mass from a similar creature using the cube-square law. If an animal is a bigger version of a similar animal, then you can cube the difference in length (or height) and multiply that by the mass of the similar animal to get the mass for the second one.    

 

Anyway, once you had the SIZ you could use the cube square law to get a STR score. You see strength changes at the rate of the mass^(2/3). Now since the SIZ table in BRP is a logarithmic doubling progression (x2 mass= +8 SIZ) it means that STR changes at 2/3rd the rate that SIZ does (that is if you  are being realistic. For fantasy creatures, and even for a lot of real animals the STR die roll is often the same as the SIZ die roll). And CON seems to change at the same rate as STR. DEX usually decreases slightly as animals get bigger (more mass to move, and usually less muscle per kg of mass to do it with), armor rating is tied to damage bonus, natural weapon damage is tied to SIZ (bigger critters tend to have larger claws and teeth), and most other game stats can be worked out along those lines. 

 

So, if the Brown Bear had an average mass of around 200-218kg  (SIZ 24-25 per RQ3) and the Kodiak Bear had an average mass of 380-400 kg (SIZ 31-32 ) and a max SIZ a bit more than 680 kg (SIZ 38). We can work of a SIZ die roll of of 3D6+21 (24-39, ave  31-32). Now since most creates have STR scores comparable to their SIZ you might want to give it the same die roll for STR, instead of the 2/3rds rate.  And go on down the line from there. The final set of stats you'll get would probably be fairly close to those of the RQ3 Polar Bear. Which would be too far off the mark.

The cool bit, from out standpoint was that we set everything up in spreadsheets and a database, so you could take some animal for which you had very little data, and extrapolate decent usable game stats based on what you did have, plus the game stats of similar creatures. The final stats might need some adjustment, but they were close enough to work. 

 

 

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2 hours ago, Atgxtg said:

I could (and at times havve done so), but I don't think that many people are interested. I could send you some of my notes. Most of my notes are a bit rough. Some things weren't locked down and I charged a few formulas on the way. 

 

I believe this should be googleable. Please start a thread! It's not as if this would take any mentionable amount of disk space on the server.

 

2 hours ago, Atgxtg said:

The mass of the animals. The way it worked was that you'd start off with an animal you wanted to get stats for For example, a Kodiak Bear. The you'd look for stats for a similar creature - that is another bear. Let's say a Brown Bear. Then you'd would check the differences in mass between the two, and convert both of those into SIZ stats using the SIZ table. For dinosaurs it was a little tricker, since we didn't always have a mass for a given dino, and would have to extrapolate the mass from a similar creature using the cube-square law. If an animal is a bigger version of a similar animal, then you can cube the difference in length (or height) and multiply that by the mass of the similar animal to get the mass for the second one.    

 

Anyway, once you had the SIZ you could use the cube square law to get a STR score. You see strength changes at the rate of the mass^(2/3). Now since the SIZ table in BRP is a logarithmic doubling progression (x2 mass= +8 SIZ) it means that STR changes at 2/3rd the rate that SIZ does (that is if you  are being realistic. For fantasy creatures, and even for a lot of real animals the STR die roll is often the same as the SIZ die roll). And CON seems to change at the same rate as STR. DEX usually decreases slightly as animals get bigger (more mass to move, and usually less muscle per kg of mass to do it with), armor rating is tied to damage bonus, natural weapon damage is tied to SIZ (bigger critters tend to have larger claws and teeth), and most other game stats can be worked out along those lines. 

 

So, if the Brown Bear had an average mass of around 200-218kg  (SIZ 24-25 per RQ3) and the Kodiak Bear had an average mass of 380-400 kg (SIZ 31-32 ) and a max SIZ a bit more than 680 kg (SIZ 38). We can work of a SIZ die roll of of 3D6+21 (24-39, ave  31-32). Now since most creates have STR scores comparable to their SIZ you might want to give it the same die roll for STR, instead of the 2/3rds rate.  And go on down the line from there. The final set of stats you'll get would probably be fairly close to those of the RQ3 Polar Bear. Which would be too far off the mark.

The cool bit, from out standpoint was that we set everything up in spreadsheets and a database, so you could take some animal for which you had very little data, and extrapolate decent usable game stats based on what you did have, plus the game stats of similar creatures. The final stats might need some adjustment, but they were close enough to work. 

 

 

This is quite insightful. Many thanks!

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