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Alternative 'crunchy' design systems for BRP


The Tweaker

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I will start with a quote from Joseph Paul, taken from this thread:

Why do you think so? I mean I can understand if some fans do not want to do that kind of work and are willing to fudge just what the capabilities of vehicles, and equipment are but there are others that would love to get down to business and work out reasonable (or outrageous) technological progress for different civilisations both past and future.

Fortunately, there are a lot of design systems out there which should be easy to adapt to BRP, so we don't need to clutter the new book with one.

I would recommend using EABA's Stuff! by BTRC, which provides a set of very interesting and not-too-difficult-to-use systems for designing weapons and vehicles of any kind, creatures, gadgets and even entire civilizations. I think it is absolutely superior in every respect to GURPS Vehicles and most other such systems in the market. As the final results are easy to translate into real-world terms, they should be as easy to translate into BRP

Other system which should be easily compatible, according to their author, are the weapon, starship and vehicle design supplements for Flying Mice's sci-fi games (Starcluster, FTL Now and Cold Space). Their engine also seems to use percentile number as its main mechanic, but I know little more about them.

So... any other suggestions?

Happy owner of number 226 of 420

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For sci-fi, Cthluhlu Rising could be a nice supplement. And that's BRP allready, with just a tiny taste of CoC. ;)

Sverre.

You are right, Sverre. I forgot about that one. A very cool CoC/hard sci-fi project. I liked the descriptions of gear, vehicles and starships. That, and End Times.

Happy owner of number 226 of 420

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It looks like people are seeing two different models here.

One is the make it from the ground up model whicj includes things like Tweaker's suggestion of EABA's Stuff and Flying Mices design supplements. Other things that would fall into that category are The GURPS vehicle design books, HEROs vehicle design books, BTRC's VDS book, and the various iterations of Traveller's design sequences.

The other is the Rip and Convert model. Find a game that has the stuff you want in it and convert the stats to your game.

The former gives you control over what you create - it is just right. The latter allows you to use all of the previously published gearhead stuff for your game with out having to wade through real world stats. The problem of course is jiggering together the formula that tells you what a T:2000 pennetration rating should equate to in BRP or how much 20 centimeters of Traveller bonded superdense stops.

Any gearheads want to take a crack at providing conversion (how to) info on the BRP Wiki?

Joseph Paul

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Joseph Paul

"Nothing partys like a rental" explains the enduring popularity of prostitution.:eek:

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I used to do a lot of conversions. I might take a crack at it.

Personally, I think the EABA/stuff! thing would be the way to go. BRTC'S 3G and VDS systems are probably the best/most accurate design rules out there and Stuff was based on those, but simplified. In effect we get a nice compromise between crunch and simplicity of play. You can pretty much design a tank, gun, etc in a couple of minutes. Then if you desire you can use the optional rules to fine tune your design.

I7ll pull out CoC and try to get a correclation between weapon damages. Should be able to do the same with stats. Just have to TIE EABA7s doubling scale to RQ/BRPS (assuming they are still using the +8 SIZ per doubling in BRP).

Chaos stalks my world, but she's a big girl and can take of herself.

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Atgxtg- When I did that recently I found that CoC pistol damage was way overrated and that there were other anomalous figures. I would be interested in seeing your results as a check on my own.

"+8 SIZ per doubling in BRP" What does this refer to?

Joseph Paul

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Joseph Paul

"Nothing partys like a rental" explains the enduring popularity of prostitution.:eek:

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Atgxtg- When I did that recently I found that CoC pistol damage was way overrated and that there were other anomalous figures. I would be interested in seeing your results as a check on my own.

"+8 SIZ per doubling in BRP" What does this refer to?

Joseph Paul

Pistol damage might be overrated. It also depends on what edtion of CoC you use, too. I once started working on a correlation between CoC/RQ weapon damages and 3G, the weapon design system for BTRC products (Stuff! weapon rules were developed from it). The neat thing about 3G is that you can take real world data, plug it into the formulas and get rather decent game stats.

In fact, if I just converted the 3G weapon ratings over to BRP most weapons and pistols would be within a die size or two (d8,d6, etc). The tricky part would be working out the scale BRP uses for rifles and heavier weapons. 3G is better than Stuff! for this sort of thing, but Stuff! is much simpler.

One key thing about most weapon stats is that few games use (or should use) a linear formula for determining damage. Most RPGs use some sort of scaling system for weapons and armor, fso a direct linear conversion gives ridiculous results. Especially when location makes such a bit difference in the effects of a hit.

The +8 SIZ doubling comment refers to the SIZ chart from RQ3, and I think the one for CoC ,too. For every doubling of the mass, SIZ goes up by 8, at least for the bulk of the table. That would help in working up SIZ scores for mecha and such. In EABA an improvement of +2 or +3 is a doubling of a value (twice as much mass, twice the speed, twice the distance). So if I can work out the ratio (like +2 mass in EABA is worth +8 SIZ in BRP, for x4 ratio) then conversion gets easier.

Chaos stalks my world, but she's a big girl and can take of herself.

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Atgxtg- When I did that recently I found that CoC pistol damage was way overrated and that there were other anomalous figures. I would be interested in seeing your results as a check on my own.

"+8 SIZ per doubling in BRP" What does this refer to?

Joseph Paul

How so? As it is it is impossible for a low caliber handgun to kill a moderate sized person, and even a moderate handgun cannot kill a decent sized person easily. Only the .45 and up have a real shot at it, and often require an impale.

The BTRC stuff seems to based on energy alone, which is a very flawed way of translating real world guns to Damage in a game, especially HP based games.

The damage roll is a result of two things, an abstraction of the weapons capabilities to damage a person or thing, and the location of the hit - which is not affected by energy at all. A shot to the heart or brain with a .22 probably as bad as one with a .45.

Second, higher velocity rounds often easily penetrate targets and so only transfer a part of their energy to the target, while a slower round may not penetrate, and so ALL of it's energy is absorbed by the target. I see BTRC rates a 9mm higher than a .45 (because of it's higher velocity) - but the 9mm is more likely to go through the target, while the slower, bigger .45 is more likely to transfer more or even all of it's energy to the target.

That is the principle behind Armor Piercing rounds and soft lead or hollow point rounds. Armor Piercing rounds are made of very hard material and teflon* coated and designed for maximum penetration of body armor - but they tend to make neat little holes in soft targets, while a lead or hollow point is designed to NOT go through a soft target, but to expand, fragment, and generally cause as much tissue damage as possible while transferring all of their energy to the target - but they tend to just splat against armored targets. The important thing that two rounds are going to travel at the same velocity and have pretty much the same mass - so the energy will be practically identical, while the damage will be very different.

*The teflon is actually not to aid penetration - a bonus cookie to anyone who knows why AP rounds are teflon coated.

Help kill a Trollkin here.

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Rurik,

Actually you can inflict a lethal wound with any weapon. It is just a question of how fast it takes to kill the guy, and if they are incapacitated or not. That is what I loved about TIMELORDS and CORPS.

THe problem is that most RPGs tend to focus sorly on enegy/power rather than placement. A .25 ACP round through the Eye is a lot more damaging than a .50 cal round round through you left pinky (unless said piky is in fromnt of the rest of you).

The 9mm/45ACP argument is way to complex for BRP. While I agree with you about over penetration, there is aslo the fact that even if a weapon transfers all of it energy, it doesn't mean that much it it is spread over to large an area. Most rifle round will overpenetrate a human body but still inflict more damage on the way through than slower mocving rounds.

Chaos stalks my world, but she's a big girl and can take of herself.

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Rurik,

Actually you can inflict a lethal wound with any weapon. It is just a question of how fast it takes to kill the guy, and if they are incapacitated or not. That is what I loved about TIMELORDS and CORPS.

Sorry, I wasn't clear. I'm with you 100%. I was responding to:

Atgxtg- When I did that recently I found that CoC pistol damage was way overrated and that there were other anomalous figures. I would be interested in seeing your results as a check on my own.

With:

How so? As it is it is impossible for a low caliber handgun to kill a moderate sized person, and even a moderate handgun cannot kill a decent sized person easily. Only the .45 and up have a real shot at it, and often require an impale.

I was referring to with the COC rules. A .22 is not going to kill anyone with decent HP in the game, which is to me unrealistic. If you underpower handguns even more, as Joseph Paul suggests, you would be moving farther from reality. That's why I go on to mention the .22 to heart and brain. I'm pretty sure we are on the same page here.

Rifles actually over-penetrate, but have so much MORE energy even the fraction that is transferred to the target does massive tissue damage. Personally, I think mass matters more than velocity in damage (again favoring rifles), but that is subjective. That is why I think it is OK to give the .45 ACP higher damage than the 9mm. Personally I think the CoC damage values are good.

Pure kinetic energy based formulas are flawed. I look back at Aftermath! which did the same thing. .25ACPs couldn't hurt a fly and no one could possibly survive a high powered rifle - which is wrong. The reason people like them (formulas based on energy) is they can be accurately measured and calculated (though how come games that do this don't adjust damage dramatically with range as the velocity drops is beyond me). You come up with formulas that try to account for the other variables (range, target composition, mass, gravity, etc) but ultimately you are just arbitrarily assigning values in complex formulas - which is really not that different than arbitrarily assigning a value of say, 1d10+2 to a .45 ACP.

Help kill a Trollkin here.

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Rurik wrote:

The damage roll is a result of two things, an abstraction of the weapons capabilities to damage a person or thing, and the location of the hit - which is not affected by energy at all. A shot to the heart or brain with a .22 probably as bad as one with a .45.

You are right and I would put forward that we are, wrongly, compensating for damage to major organs and the central nervous system by inelegantly upping the damage of pistols. Yet strangely we have weak rifles in BRP. Do you doubt this? I don’t after realizing that a .45 ACP has 68% of the average damge that a .30 06 does (7.5 pts to 11 pts.)

Arguments about energy transfer and overpenetration are moot in the face of such inelegant mechanics. For instance let us shoot a very large target, an elephant perhaps, such that the rifle round cannot overpenetrate and lose in the E-transfer lottery. Assume maximum damage from both rounds; 12 for the pistol and 16 for the rifle. The pistol does 75%(!) of the damage of the rifle. Hmm that is pretty good given the large difference in the RW energies of the two rounds, 412 and 2800 ft/lbs at the muzzle. Since pistols get more shots per turn than rifles we should hunt elephants with .45’s eh?

I suggest that pistols be toned down so that firearm damage and later weapon developments can be rationally added as needed. Further the ability of high velocity projectiles to stop or kill a target needs to be based on where the shot lands. There are plenty of ways to abstract that so that we get any degree of lethality we want and yet don’t make super weapons out of pistols. Edit: and we keep the mechanics clean.

Joseph Paul

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Joseph Paul

"Nothing partys like a rental" explains the enduring popularity of prostitution.:eek:

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Just a thought here...

perhaps one should consider basing the damage on the size of the round, and the RANGE on the velocity / barrel length.

really, a pistol and rifle of the same calibre do much the same amount of damage, the rifle just does that damage farther away.

most pistols aren't using rifle ammo, even if the calibre is the same, I know this; it's because having a powerful round is useless if you're not sure where it's going to go - the limited range of pistols puts a cap on the useful power of the round.

but, comparing apples to apples, the same round will go further fired from a rifle than from a pistol, and more accurately.

the damage done by the projectile decreases with distance, and that decrease is less with a longer barrel.

I don't think a 'perfect' method will ever come by - and even if it did, it would probably be unplayable - but it seems that damage would be determined by calibre and muzzle velocity, and range (and damage reduction) would be determined by muzzle velocity and barrel length (and rifling, of course)

I'm not as concerned with bullets as I am with shrapnel and burst fire. Shotguns, grenades, and automatic weapons are hard for me to deal with (perhaps I need Cthulhu NOW), I just treat them as area effect attacks.

The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done."

George Carlin (1937 - 2008)

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I'm not into ultra detailed rules, so this will go beyond my interest level quickly, but I'll add some comments here.

I was referring to with the COC rules. A .22 is not going to kill anyone with decent HP in the game, which is to me unrealistic. If you underpower handguns even more, as Joseph Paul suggests, you would be moving farther from reality. That's why I go on to mention the .22 to heart and brain. I'm pretty sure we are on the same page here.

It should be virtually impossible to kill someone with a .22. Your shots to the eye or heart are both going to result in bleeding out over some time before death for an adult human.* As long as an impale can lead to serious damage you're fine. In fact, I'd say that a .22 round, especially a short, should have a very hard time even disabling a limb from a shot. They hurt like hell and can be very dangerous if you get hit in the right place of course, but aren't going to be fatal for anything larger than 20-30 lbs in general...and even those you need to hit square. If you don't nail a rabbit between the eyes with a .22, there's a very good chance it'll get away.

* Though to be fair, even a high powered rifle should generally result in a wound that bleeds out over some time. It's pretty darn hard to outright kill someone with a single bullet. Massive bloodloss that can't be fixed with first aid is what kills most of the time and it takes some time: minutes to hours.

Rifles actually over-penetrate, but have so much MORE energy even the fraction that is transferred to the target does massive tissue damage. Personally, I think mass matters more than velocity in damage (again favoring rifles), but that is subjective. That is why I think it is OK to give the .45 ACP higher damage than the 9mm. Personally I think the CoC damage values are good.

Pure kinetic energy based formulas are flawed. I look back at Aftermath! which did the same thing. .25ACPs couldn't hurt a fly and no one could possibly survive a high powered rifle - which is wrong. The reason people like them (formulas based on energy) is they can be accurately measured and calculated (though how come games that do this don't adjust damage dramatically with range as the velocity drops is beyond me). You come up with formulas that try to account for the other variables (range, target composition, mass, gravity, etc) but ultimately you are just arbitrarily assigning values in complex formulas - which is really not that different than arbitrarily assigning a value of say, 1d10+2 to a .45 ACP.

Damage is done through kinetic energy transfer. That's basic physics, but I suspect different from what you're saying. However, that isn't really the issue from what I see. The issue is that angle and location of the bullet are more important than the specific weapon/bullet used, so if you want "realistic" make all missile weapons have extremely wide ranges of damage. They should all be able to deliver a single point of damage, so don't use any set "adds" to them. Instead use bigger dice for more powerful weapons, so potential maximum damage increases but minimum damage doesn't change.

Having said that, I could also see an argument for making them all 2 dice so that the extremes are rarer and the average damage is more set. I still like one die, as of now.

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It may be time to refine and define the question(s) better. It may also be time to move this to its own thread.

1) A review. In discussing possible design sequences for BRP it was put forward by me that firearms have anomolies compared to other games that rely on RW data and not on the needs of the designers. Specifically that pistols are overpowered compared to rifles and that damage done by other long arms seems to follow no rhyme or reason.

2) Point made that it is within current pistols' game capabilities to supply a major wound that will stop a human target.

2a) Point made that in BRP it is hard to kill humans with pistols in the game at least in one shot.

3) First thing to decide- Is the goal to kill (bring to 0 HP) or stop (render incapacitated) a human target? RW data looks at stopping a target. Shot at, stopped, and still living is the norm in armed conflicts. This is because there are many ways targets are stopped. Physical force, pain, psychological stresses, and disorientation are some of them.

I would opt for stopping a human target to be the reality check here.

It has been pointed out that as in real estate the primary concern in wound ballistics is location, location, location. ;) However even this is not as straight forward as we would like (is anything as complex as this ever straight forward?).

The concensus in the wound ballistics community appears to be that stopping a human can happen several ways.

Disorientation by the firing of the gun. Bright flash and loud noise actually stunning a person and rendering them incapable of action for a time.

Pain from an otherwise non-life threatening wound causing the target to be incapable of continuing. No structural damage (ie to organs, arteries or bones), just pain.

Damage to the body resulting in bleeding or loss of pumping efficiency. Deprived of freshly oxygenated blood the target will faint soon and then bleed out.

Damage to the central nervous system that results in unconciousness, paralysis, or death. Bullets stretch and pull on surrounding tissue creating temporary cavitation. A bullet does not have to hit the spine for instance to jar it hard enough to affect the spinal cord.

Bullet/body interaction are complex but I think that what needs to be modeled are targets' reactions to having small bits of metal forced through their body at high speed.

We see examples where round after round is fired into a target to no avail.

Apparently the rounds are not hitting organs,arteries, bones, or the CNS. In game terms the targets HP need to be ablated.

We see examples where an underpowered round drops a target. Apparently it did affect organs, arteries, bones, or the CNS. Currently we can not get this result in BRP/CoC.

I am currently working out a system where the target takes the HP damage but rolls d20 vs CON or HP in a location to avoid being dropped by damage to the CNS, which is after all a distributed system. I chose CON as a representation of the toughness of the tissues and to link it to the target. Same idea can be applied to determining damage to organs, bones, and arteries by rolling d20 vs POW which would determine bleeding. I am working out simple modifiers for hit location (currently limb, torso, and head) as well as the amount of damage to those locations modifying the roll (limb- none, torso- damage).

A point of damage from a .22 to a limb is very survivable. Roll vs CON to continue to act.

A 5 point shot to the torso. Roll d20 vs CON-5 to avoid incapacitation

A point of damage from a .22 to the head. Roll vs the HP in the head (CON/3 if you don't want to use hit location HP). If you make it no incapacitation. If you fail you drop and go unconcious.

If that is to complex then you could abstract the ability of firearms to incapacitate by rolling d100 vs 5x(POW-damage).

Success- take HP damage.

Fail- take damage and incapacitated.

Fumble- Take damage, incapacitated, and bleeding.

Use POW because hitting the CNS is more luck than anything else at this level of resolution.

Oh yeah do this for each round that hits. Multiple shots gve multiple chances for incapacitation.

I need to run some numbers on this stuff to see how it performs. It should allow pistols to be effective at stopping a human target with out requiring them to be overpowered in relation to other weapons.

Joseph Paul

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Joseph Paul

"Nothing partys like a rental" explains the enduring popularity of prostitution.:eek:

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Sorloc,

You might want to look at 3G (Guns! Guns! Guns!), the weapon design system used for Timelords and CORPS. Basically that's what Greg Porter did.

Weapon damage was mostly a factor of the energy of the weapon, bullet diameter, and range.

If the cases of pistols and rifles that use the same ammo (like a .22LR), the rifle did benefit from a slightly higher energy due to optimum barrel length (most bullets need a certain length of barrel to reach maximum energy, too short and some energy is lost). Weapon damage does drop off over range, too. So a .22 bullet at 1000 yards isn't nearly as nasty as, say a .45 at 10 yards.

The system is playable and fairly accurate.

The big twist to Timelords, and CORPS is that they don't use the typical losing HP model for reflect injuries. So weapons that inflict lots of damage are not guaranteed kills, nor weapons that do a little damage just stuff you can shrug off. They way it works is that the damage taken determines how likely a wound is to be fatal as well as how much time you have to do something about it.

COPRS is the simpliest. What it does is use the damage taken at the chance of a wound being EVENTUALLY fatal (rolled on a d10, CORPS is d10 based). If a hit is eventually fatal, then the die roll is then number of minutes you have before you start to loose health from bloodloss. then the time increment doubles until ou run out of health, or get treated. Hit Locations give a +/-1 modifer to the leatality (head hits more lethal, limb hits less so).

The actualy damage points taken are used as the impairment for tasks attempted with the damaged location. So a rifle round through your arm won't kill you right away, but will mess up your penmanship.

Timelords is more complex, but divides the body into 31 hit locations. THis way not all chest hits are alike. Depending on where you hit, a bullet can go right through with little immediate effect, or drop the guy like a poleaxe.

Chaos stalks my world, but she's a big girl and can take of herself.

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Sorloc,

Timelords is more complex, but divides the body into 31 hit locations. THis way not all chest hits are alike. Depending on where you hit, a bullet can go right through with little immediate effect, or drop the guy like a poleaxe.

Some of the Tri-Tac games ended up with a system like that taken a step further. Hit locations were blown up into 6x6 grids to determine exactly where the round hit and then you could find out if you hit bone, severed arteries, smashed organs etc. You could also just nick the shoulder.

One of the ways to make things like this work faster is that the aggressor throws multiple color coded dice to determine hitting, location, and damage. It gets pretty easy to read fast.

Joseph Paul

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Joseph Paul

"Nothing partys like a rental" explains the enduring popularity of prostitution.:eek:

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Some of the Tri-Tac games ended up with a system like that taken a step further. Hit locations were blown up into 6x6 grids to determine exactly where the round hit and then you could find out if you hit bone, severed arteries, smashed organs etc. You could also just nick the shoulder.

One of the ways to make things like this work faster is that the aggressor throws multiple color coded dice to determine hitting, location, and damage. It gets pretty easy to read fast.

Joseph Paul

A simpler way to do it, and one close to BRP is what the James Bond RPG did. In that game the damage a weapon did varied based upon the quality rating (think success level) of the shot. A good quality rating meat a hit tot he vitials for more severe effects (KILL, INCAPCITATE, HEAVY WOUND), while marginal quality rating hits were grazes and such and did less damage. This meant that while rifles were usually more damaging on average, a well placed pistol shot could be deadly. Great for a setting where the main character carries a .25 ACP Beretta.

The game even had a few options that could port over, like a called shot for more damage that increased the damage done, but at a penalty to hit (about half skill in BRP terms). The game also had an aimed shot option (took a turn, but shot at 1 1/2 skill), and the two options could be combined.

Something like 1 die, 2 dice, 4 dice for damage might do it.

Chaos stalks my world, but she's a big girl and can take of herself.

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