If you can play a game that has HP plus a (usually small) pool of "meat points" then the answer is that called shots don't work until the HP are depleted. After that, the called shot helps determine how you take them out (lethally, crippling, subdual, etc.). The d20 Star Wars lines had Vitality Points & Wound Points, but I don't believe it did anything like this with called shots.

Another way to do it (that doesn't require a major system overhall) is to have called shots trigger saves to avoid and give a bonus based upon how many HP the target currently possesses.

Quote from: Steven Mitchell on October 16, 2024, 04:35:10 PMI'm tempted to write something into the rules that explains that the default is that every effective attack is a "called shot".  People that use weapons to try to kill others and keep themselves alive don't just flail around randomly.

No. Instead they look for opportunities to strike an unprotected place. This opportunity comes up when the opponent drops their defence to make a strike themselves. They are not deliberately attacking a random place, but they do have an opportunity to attack a random place; they do not have as many opportunities to attack the place of their choice.

However, you inadvertently bring up an important point: framing. Players perceive a -X on a roll to be bad, and a +X on a roll to be good. However, these two can be functionally the same.

If we have a system where you need to get 6+ to hit on a d6, and called shots are +0, and random shots are +1, this is exactly the same as a system where you need 5+ on a d6, called shots are -1, and random shots are +0. Exactly the same odds - but it feels different to the player.

If you frame things as always being a bonus of one level or another, players are more likely to choose freely among them, as opposed to one thing being a malus and another a bonus, where they'll be reluctant to choose the malus.

However, like the miniature wargames, D&D sprung from it, not going to address specifics of individual injuries in the way that GURPS or Harnmaster handles it. But combat can be extended in an OD&Dish way that is consistent with how other "Bad things a character can suffer" are handled.

Quote from: tenbones on October 15, 2024, 03:23:54 PMTheres lots of ways to do it. Depends on what you're after. If you're looking for "realism" and you want it backed up by mechanical effects then you need to also consider how your "degrees of damage" are going to play out on each bodypart.

Neither GURPS nor Harnmaster cares about degrees of damage to various extremities. Instead there are thresholds when something "bad" happens. In Harnmaster wounds force saves (stumble for legs, fumble for arms), grievous wounds may result in amputation or crippling of the limb. But unless amputation occurs then there is no further effect on the limb itself. GURPS is similar except it has more conditional saves and modifiers to damage like capping the amount of hp damage the character can suffer if a limb is struck. As far as the limb itself goes for both it is either usable or it is not.

Quote from: tenbones on October 15, 2024, 03:23:54 PMAgain - I hate to be a broken record. Literally everything you covered in your system is almost verbatim with how Savage Worlds operates.

While I enjoy GURPS and Harnmaster more as a ssytem. I found through extensive playtesting that combat can be more grounded and better reflect the outcomes I had with GURPS and Harnmaster while keeping it classic D&D and compatible with the various supplements and adventures out there.

As the editions progress it becomes more difficult particularly after and including 3.0. There are more moving parts resulting in a more complex job. Which is why I started out with OD&D 3 LBBs and a little bit of Greyhawk in the form of S&W Core.

Quote from: tenbones on October 15, 2024, 03:23:54 PMYou could convert that to d20 by dividing your HP to your various body parts and assigning them like baby-Battletech rules? At 50% or lower you start racking up penalties. Not sure how granular you want to make it. Definitely could be done.

Once you start jettison everything from the original system then it little better than starting with a blank piece of paper. You are looking at a handful of years of playtesting hopefully with a variety of different group if the author really wants to nail down that it is working as intended.

I focused mostly on character classes with my Majestic Wilderlands supplement, and tried it out in a single campaign. But from 2010 to 2016, I ran a bunch of campaigns, and convention games tweaking and testing until I arrived at what I had today. Not unlike what Perrin did going from D&D to Runequest but stopping well short of jettisoning everything.

Quote from: tenbones on October 15, 2024, 03:23:54 PMIt gets to the old question of "what are HP?".

I found treating Hit Points as an abstract measure of combat endurance as opposed to representing levels of injury solves a lot of issues in figuring out how to make classic D&D combat more grounded in how combat in life works.

Quote from: tenbones on October 15, 2024, 03:23:54 PMTheres lots of ways to do it. Depends on what you're after. If you're looking for "realism" and you want it backed up by mechanical effects then you need to also consider how your "degrees of damage" are going to play out on each bodypart.

Last, if the referee wants to make hit location a regular part of resolving D&D combat then the next D&Dish step is to come up with a hit location chart that is used after every successful hit. If the damage is less than 5 hp then there is no further effect except for a blow to the head for a target without a helm. They would have to make a save or be stunned for a round.

If the amount of damage is HP 5, then a save would have to be made, or a more consequential result will occur. Long lasting stuns for head shots without helm, short stuns even with a helm, fumbling something with a arm hit, stumbling with a leg hit, etc.

The most serious result would occur with a critical hit. If my system with a exploding d20 then I would specify saves for results with a natural 20 only, a natural 20 and the second roll hits,  then multiple natural 20s in row. I would start with a broken limb moving up to amputation results with a single swing on successive natural 20s.

Rob's Note: the most I seen a player roll was four nat d20 in a roll. Two and rarely three comes up once in a blue moon in a campaign. Rare but not unkwown.

Quote from: Kyle Aaron on October 17, 2024, 07:05:00 AMHowever, you inadvertently bring up an important point: framing.

It wasn't inadvertent. 

Quote from: Steven Mitchell on October 16, 2024, 04:35:10 PMI'm tempted to write something into the rules that explains that the default is that every effective attack is a "called shot".  People that use weapons to try to kill others and keep themselves alive don't just flail around randomly.

That's my attitude with it, especially as regards combat between humanoids, though I'd probably phrase it the opposite way: If you're fighting someone who is armed, armored and trying to kill you, you don't get to call your shots; you take the opportunities you can get.

The way I see it, the only way to make sense of the D&D combat system is that the "to-hit" roll is really a "to-wound" roll. Hitting someone and failing to wound them is covered under failing your attack roll. Called shots would only make sense to me in a game where connecting with the target and bypassing their armor are covered by separate rolls.

While prowlers doesn't have a mechanic specifically called "called shot", it does have a couple of mechanics that can achieve results similar to some of the actions mentioned in your post.

Combat stunt is the most generic mechanic in this category, and has the advantage that it works however the player describes, dice willing, and if the GM agrees. Example effects include penalties to rolls, reduced speed, disarmed, immobilized, lose a turn. Combat stunts may also be used to imitate certain special effect powers, such as blind, ensnare, deafen, or irritant. The book goes on to provide a handful of examples of typical combat stunts a player (or foe) might use. No combat stunt will defeat a target on its own, and none of them deal damage.

Using the effects listed in your post as a guide, combat stunts give us rules for stun, drive, trap, free, stagger, shatter, bind, knock down, disarm, and they all work the same way, using various traits to perform them and defend against them. Some of these effects are also available as dedicated powers.

Furious attack and defense are covered under a separate set of mechanics, called all-out attack and all-out defense, respectively.

Striking multiple opponents is something anyone can do with no special rules needed. This is typically accomplished with the Area pro on a power, ability, or weapon. However, even without an area attack, anyone can attack multiple foes in a single page by taking a penalty to their rolls. Also, whenever you fight minions, you will usually be defeating more than one minion with a single attack.

Of course there are multiple ways to implement any particular action that a player imagines. For example, a GM might decide to use grappling instead of combat stunts to represent trap, free, and bind, depending on what's appropriate for the situation.

As for your question, I consider them to be one of, if not the most fun part of the combat system, possibly of the entire game. They allow players total freedom in how they express themselves through their character, and allow them to represent anything they feel their character would be capable of with consistent rules that never make any other mechanics irrelevant. Whatever you design your character to be good at, they will be good at that thing, in the way in which you intended.