In games like D&D, monster hit dice are a conflation of level and size. The larger a creature is, the more hit dice: dinosaurs can take a lot of damage. Meanwhile, a monster's "level" also apparently affects its hit dice: an apatosaurus is larger than Tiamat, but only a fraction of her hit points (5e, maybe others).
I find this makes it difficult to model some creatures. As an extreme example for the sake of demonstration, consider the Giant Baby. It's 25' tall sitting down, and less than a year old (in human lifespan terms). It flails about with its hands, barely capable of aiming, but if it gets lucky the damage is severe.
Should this creature's hit dice be high?
Should it be harder to kill than a normal-size baby? If not, then shouldn't this be extrapolated to any Giant?
If so, then how do you reconcile it being hard to kill and still terrible at combat, since hit dice inform both?
From a game design perspective, perhaps there are other systems that specifically handle the concepts of level and size as independent vectors?
Level is supposed to be an abstraction of how difficult a creature is to kill, so that dungeon masters know whether it is appropriate to place in front of the party without being either trivially easy or resulting in a total party kill. Hit points would be more accurately described as plot armor (in media criticism terms) rather than physical integrity, precisely because hit points do not strictly correlate with size. If you think of HP as plot armor rather than physical integrity, then it would probably be easier to reconcile the disparities in HP between various creatures.
Quote from: BoxCrayonTales on September 21, 2020, 11:34:50 AM
If you think of HP as plot armor rather than physical integrity, then it would probably be easier to reconcile the disparities in HP between various creatures.
I have no problem reconciling disparities in HP between different creatures. I have trouble reconciling the situation where something should be difficult to kill but poor at hitting things.
The problem is that in D&D terms level and size are somewhat munged in abstract, but you can't entirely separate them without other changes too.
Take Runequest for example. RQ has a Size characteristic, no levels, but also has separate Strength, Constitution, and Dexterity and weapon skills. Depending on the exact version, you get different effects from Size. Often, it is some combination of larger Size makes the target a little tougher, easier to hit, and more effective for it to hit (in some way). Which makes sense: Easier to hit a big thing, but it also has more reach on you. I'm being overly simplistic in that description because I don't recall off the top of my heads the changes in the versions.
To me, the Giant Baby is one of those cases where the D&D abstraction breaks down somewhat. So I'd just one-off it with a big minus to hit to go with the HD. Maybe, if I wanted to be more particular, also a minus to appropriate saves.
The 3E size modifier was an appropriate abstraction for size, if a little too fiddly in practice, though even the reasoning behind it messed up reach issues. (Since small characters got a +1 AC and a +1 to hit--presumably because they could move more easily, it was handy in washing out if the same size fought. But then 3E has a separate set of reach rules that are too specific to work around the issues.)
5E makes a nod to a similar concept with monster building having size set the size of the hit dice. But then it blows that out of the water by using a formula based on actual hit points instead of gearing those to hit dice. So you get this crazy thing where a smaller creature of a given CR needs more hit dice than a larger one--all other things being equal.
I prefer to treat Level and Size as separate things. To me "Level" has always meant "degree of competence and power", while "Size" should just mean "meat points" (i.e. Hit Points as a result of body mass that make a creature harder to kill, but don't necessarily contribute to its overall competence). D&D doesn't handle this very well, but the way I would handle it is to treat "Level" as the thing that determines things like Attack Bonus/Thac0, Saves, Skills, Proficiency Modifier (in 5e), etc. along with base number of class-based Hit Dice, then treat the creature's Size category as something that grants bonus HD that don't affect anything level related, as well as a bonus Strength and Constitution, and other size related benefits (bonus to resist knock downs, etc.) and penalties (reduced chances to sneak, a penalty to Dexterity score perhaps, etc.).
Based on 5e Size categories (Tiny, Small, Medium, Large, Huge, or Gargantuan), for example, each size category above Medium could grant perhaps a +4 to Strength and Constitution, +4 to special attacks (bulrush, etc.), and +3 Hit Dice, but impose -4 to Dexterity, -1 to AC and -2 to Stealth. While each size category below Medium could grant +2 to Dexterity and Stealth, but impose -2 to Strength and Constitution. Obviously these could be adjusted based on system/edition and such, and STR/CON bonuses are compared to human 3-18 scale when creating new creatures rather than thrown on top of an existing Monster Manual large creature's scores, but it provides a general idea of how to treat Size separate from Level.
In old school D&D and third edition, there was a minimum HD for each size. In 3e, this doubled with each new size category. So if your base is 1 HD at medium (humanoids), then a gargantuan version (size +3) would have at least 8 HD. Though humanoids are remarkably puny -- most animals or monsters are 2-3 HD at medium, making then 16-24 HD at gargantuan. Anything on top of that reflected toughness, which isn't the same as level. After all, toughness scales with size, but levels are added linearly. I.e. a tough small creature like a raptor might have twice the HD of a normal small creature, and the same would be true for a tough Huge creature like a tyrannosaur, but +3 levels is +3 levels, whether you are small or large. Earlier editions like AD&D followed this pattern fairly well, though they were less explicit about it. All other things being equal, twice the HD means twice as big (and 8 times as massive).
One idea I toyed with is using the dice to represent size. So a small creature would use d4s for it's hit dice, medium would use d6, etc.
Quote from: Ratman_tf on September 21, 2020, 01:10:06 PM
One idea I toyed with is using the dice to represent size. So a small creature would use d4s for it's hit dice, medium would use d6, etc.
I've been playing this way for years now and it works great. Hit dice are determined like in OD&D and the size of the die is based on the creatures size with d8 being medium or human sized.
The three main advantages are that it separates the monsters skill from their toughness so large monsters don't automatically have better to-hit numbers. Also, it makes it easier to make classed monsters, such as giant wizards. Finally, I use the size die to determine a character's damage, so an ogre sized sword does more damage than a pixie sized one.
Quote from: Ratman_tf on September 21, 2020, 01:10:06 PM
One idea I toyed with is using the dice to represent size. So a small creature would use d4s for it's hit dice, medium would use d6, etc.
This is how 5e does it with creature hit dice (class level hit dice are different) but, IIRC, medium is d8 and it adjusts from there.
5e:The giant baby would not have Proficiency with attacks, it would have a to-hit bonus derived purely from STR which seems fair enough to me.
It will have at least one Hit Die, size determined by its size, eg Huge baby gets at least 1d12 hp.
Quote from: Zalman on September 21, 2020, 11:11:43 AM
Should this creature's hit dice be high?
Quote from: Zalman on September 21, 2020, 11:11:43 AMIf so, then how do you reconcile it being hard to kill and still terrible at combat, since hit dice inform both?
Giant Baby[/font]
A giant baby crawling along the countryside, unwittingly causing terror as it "plays" with the "toys" it finds along its path.
Giant Baby (Swords & Wizardry)AC 9[10]; HD 16; HP 70; Save 3;
Move 30'; CL/XP 10/1,400;
Attacks (x1)Fists; HTB +8; DMG 4d6;
Special[/font]
Mind of a baby: The infant mind of a giant baby means that it only "fights" at half its hit dice (8 HD). The fact it is only that high is because of its enormous size and reach.[/size]
A Baby's Grasp: On a successful to-hit roll by its fists, the target must make a saving throw. If the victim fails it is grabbed by one of the baby's hands and is effectively immobilized, unable to move or use their hands, arms, or legs. Every turn afterward the targets needs to make an additional saving throw or pass out as the baby shakes the target around as it chortles with glee.
If the target doesn't pass out then they can make another saving throw and add in their strength modifier. If successful then the victim manages to slip out of the baby's grasp. Roll 1d4-1 x 10 feet to see how far the victim is up in the air when they slip out. Falling damage may occur.
Rob's Note: Keep in mind that anything can be over ridden by the description of the monster including what the creature attack as. For example see the Bulette and its description of how Armor Class work which is an exception to the normal rules of Armor Class.
Using different size hit dice is interesting, though I feel that already represents a different vector still: class. Conflating those would seem to make it tougher to model, say, a Giant Wizard vs. a Giant Fighter. I also feel like the scale is too short ... where do you go from d12?
Adding "meat points" (or meat dice perhaps?) on top of class/level dice seems the most promising solution presented so far to me. Are there downsides to this approach? It doesn't seem very complex, especially with the maxim that "twice the HD means twice as big."
Quote from: Zalman on September 22, 2020, 01:20:32 PM
Using different size hit dice is interesting, though I feel that already represents a different vector still: class. Conflating those would seem to make it tougher to model, say, a Giant Wizard vs. a Giant Fighter.
A fourth level fighter has 4 HD while a fourth level wizard has 2+1 HD (if using the OD&D tables straight). So a fourth level Ogre fighter would have 4d10 hit points while a fourth level Ogre Wizard will have 2d10+1. Likewise, a human of those classes would have 4d8 and 2d8+1 respectively.
QuoteI also feel like the scale is too short ... where do you go from d12?
After d12 come 2d6, then 3d6, 4d6, etc. I haven't found much need for these except for Titans and older dragons.
QuoteAdding "meat points" (or meat dice perhaps?) on top of class/level dice seems the most promising solution presented so far to me. Are there downsides to this approach? It doesn't seem very complex, especially with the maxim that "twice the HD means twice as big."
This is a perfect solution if using current D&D straight up. Why they didn't do this in AD&D is beyond me since they already had rules for bonus hit points.
The reason I don't do it this way is that you'd need some sort of formula to calculate those bonus hit points so it's the same amount of work either way. Plus, as I said, I use the size die to determine the monster's damage so that's one less stat I need to list in the monster description.
Quote from: hedgehobbit on September 22, 2020, 01:38:47 PM
After d12 come 2d6, then 3d6, 4d6, etc. I haven't found much need for these except for Titans and older dragons.
Eh, so multiple dice-per-level? Aside from the fact that I personally find that aesthetically icky, the scale is a bit strange because it jumps up by 1hp on average until d12, then half a hp at 2d6, and then suddenly 3.5 additional hp at each size category thereafter. That's a tough one for me to swallow. I wonder if that scale could be done better and still kept as simple.
It might not be worth going to much effort there though, since meat dice seems pretty elegant.
Quote from: Zalman on September 22, 2020, 02:11:50 PM
Quote from: hedgehobbit on September 22, 2020, 01:38:47 PM
After d12 come 2d6, then 3d6, 4d6, etc. I haven't found much need for these except for Titans and older dragons.
Eh, so multiple dice-per-level? Aside from the fact that I personally find that aesthetically icky, the scale is a bit strange because it jumps up by 1hp on average until d12, then half a hp at 2d6, and then suddenly 3.5 additional hp at each size category thereafter. That's a tough one for me to swallow. I wonder if that scale could be done better and still kept as simple.
It might not be worth going to much effort there though, since meat dice seems pretty elegant.
For that kind of thing, I find that the Fibonacci Sequence gives me raw scaling that I like, but that it doesn't always align with dice code that well. Also, the standard sequence takes off really fast, at 2, 3, 5, 8, 13, 21, 34, 55, 89--not giving much room for multiple levels. (Starting at the technical beginning of the sequence doesn't help much, either.) What I've done instead is have the dice code hit every other level in the sequence, and then pick something in the middle that is close enough--with some judicious rounding for dice averages and a small modifier to handle not having much gaps in the early part of the sequence.
For example, let's use average dice, rounded up, with a flat modifier of +2 to the sequence. Putting a die code on every other sequence gives 4, 4, 5, 6, 7, 9, 10, 13, 15, 19, 23 (going up to 21 in the sequence where it starts to go crazy, though you could go 2 more results up to 34, 30 & 36 for really big creatures). Do a little judicious rounding down at the lower end to start at 1d4, 1d6, 1d10, 1d12, then start adding modifiers -- 1d12+2, +4, +6, +8, +12, +16, etc. After all, at the upper end of the scale, 2 extra points doesn't matter a lot.
Quote from: Zalman on September 22, 2020, 02:11:50 PM
Quote from: hedgehobbit on September 22, 2020, 01:38:47 PM
After d12 come 2d6, then 3d6, 4d6, etc. I haven't found much need for these except for Titans and older dragons.
Eh, so multiple dice-per-level? Aside from the fact that I personally find that aesthetically icky, the scale is a bit strange because it jumps up by 1hp on average until d12, then half a hp at 2d6, and then suddenly 3.5 additional hp at each size category thereafter. That's a tough one for me to swallow. I wonder if that scale could be done better and still kept as simple.
It might not be worth going to much effort there though, since meat dice seems pretty elegant.
If you care enough, get an electronic die roller and use d14, d16, d18, etc.
In AD&D, for a creature like this you'd take advantage of the X+Y hit dice rule. In AD&D a monster has X hit dice. It can also have +Y hit points; e.g., the troll at 6+6 HD. So a troll you roll 6d8 and add a flat 6 hp to the dice roll total.
Any creature with a +3hp or higher attacks as 1 HD better; so a troll attacks on the 7HD table. Not the 6 HD table. But there's no increments to this. A DM could have a super-troll with 6+99 HD, or 6d8 + a flat 99 hp - it would still attack on the 7HD table.
So for your giant baby, if you wanted it to have a lot of HP but not the attack matrix of a titan, you could give it 1HD+50hp (or whatever), and it's giant size expressed as +50hp would mean it attacked on the 2HD table.
I think it's going to vary by edition.
Where I come from, hit points actually IS meat. For the most part. The idea that it's anything else really came from having to justify high level PCs who seem impossibly tough. Most humans and near-humans in the world or 0th or 1st level, subject to one hit kills. Those hit points are all meat. Most monsters, it's all meat.
As for hit probability, understand that's conflating both the ability to hit a target and armor penetration. Larger creatures have more hit dice, which comes with greater hit probability, because their hits are forceful and are highly likely to deal damage despite your armor. This is also the justification for high STR coming with a to hit bonus.
You can always tweak or make an exception if you've got a creature that you really don't feel fits the mold. But other than that, it's a pretty handy rule for keeping things fast and simple and reasonable.
There are a lot of potential toggles that can help you create a giant baby (or distinguish between an elephant and a dragon of the same size).
While level tends to increase attacks bonuses (THAC0), you can also have proficiency and attribute bonuses, as well as size modifiers. In 3.x, a giant baby might have relatively high hit dice, but would not have proficiency with weapons, and would have a fairly hefty size penalty; if the attributes didn't give a major bonus, it'd work out pretty well. Whether it makes sense for a Giant Baby to have a STR of 10 is one you have to answer - I think it does even though that might be unusual for other creatures of that size, it might reflect the reality of 'uncoordinated attacks' better than a 25 or 30.
I do think that in the abstract it might make sense to have bonus hit points for size that are independent of level. Ie, a baby might be a 1/2 HD creature, and be Tiny. For every size you increase it, you could add extra hit points - something like +4, +8, +12, +16, +32, so going from Tiny to Medium (2 sizes) would add 12 hit points total; going to Huge (4 sizes) would add +40 hit points.
Quote from: Steven Mitchell on September 22, 2020, 02:56:23 PM
For that kind of thing, I find that the Fibonacci Sequence gives me raw scaling that I like, but that it doesn't always align with dice code that well. Also, the standard sequence takes off really fast, at 2, 3, 5, 8, 13, 21, 34, 55, 89--not giving much room for multiple levels. (Starting at the technical beginning of the sequence doesn't help much, either.) What I've done instead is have the dice code hit every other level in the sequence, and then pick something in the middle that is close enough--with some judicious rounding for dice averages and a small modifier to handle not having much gaps in the early part of the sequence.
Never got anywhere with it, but a long time ago I was thinking of writing a roguelike using the Fibonacci sequence for monster sizes, because it's a good way to approximate a geometric progression using integers (characters). Never thought of doing it in D&D, but it would be interesting to explore. Since the Fibonacci approximates the golden ratio over time (1.618etc), it's somewhat more granular than the size classes in 3e (whose linear progression advances at a factor of 2).
Size categories in 3e (minimums):
- M 1 HD, 4', 62.5 lb
- L 2 HD, 8', 500 lb
- H 4 HD, 16', 2 tons
- G 8 HD, 32', 16 tons
- C 16 HD, 64', 125 tons
- C+1 32 HD, 125', 1000 tons
Extended it one size to show the upper end of colossal. Uses weak humanoid HD. Double for a creature as tough as a wolf, triple for a creature as tough as a cat.
Fibonacci equivalents:
- 1x1 1 HD, 4', 62.5
- 2x2 2 HD, 8', 500 lb
- 3x3 3 HD, 12', 1700 lb
- 5x5 5 HD, 20', 4 tons
- 8x8 8 HD, 32', 16 tons
- 13x13 13 HD, 52', 70 tons
- 21x21 21 HD, 84', 300 tons
- 34x34 34 HD, 136', 1200 tons
Not a big change, basically inserts another size category in between M and G, at a cost of a less obvious progression in numbers. Probably more useful in a roguelike.
I think the question of how many hit points a Giant Baby has misses the more important question of, how many do we have to kill to go up a level?
Quote from: Pat on September 23, 2020, 05:51:47 PM
Fibonacci equivalents:
- 1x1 1 HD, 4', 62.5
- 2x2 2 HD, 8', 500 lb
- 3x3 3 HD, 12', 1700 lb
- 5x5 5 HD, 20', 4 tons
- 8x8 8 HD, 32', 16 tons
- 13x13 13 HD, 52', 70 tons
- 21x21 21 HD, 84', 300 tons
- 34x34 34 HD, 136', 1200 tons
Not a big change, basically inserts another size category in between M and G, at a cost of a less obvious progression in numbers. Probably more useful in a roguelike.
Yeah. My issue is that I want the progression even flatter than that--that is, hit points less inflated overall. Like the OP, in a still very abstract system, I want to distinguish between adventuring toughness versus size toughness. Consider something like BEMCI, where a huge red dragon has 20d8 hit dice, or about 90 hit points. The dragon turtle hits that next step, coming in at 30d8 hit dice. However, dragons are a bad comparison, because getting bigger is a function of vast age, and is supposed to represent size and experience. Plus, that would be putting "huge" at the FS 21 mark.
And as you noted, you want the progression to be intuitive. So I find it works better to take the sequences similar to you have laid out here, and make that the multiple of the hit points. But then reverse-engineer those expected totals to give the points from experience, size, Constitution modifier, and anything else that you want to include in that equation. It's not necessarily hard to get in the ballpark of the FS on outcomes that way, with linear hit dice for experience. Rather, it's not hard to do if you start adventurers at a slightly higher total than normal, because otherwise the scale at the bottom gets awfully cramped. Doing that, the d4, d6, d8, d10, d12 hit dice for size can be made to fit, with a little fudging on what the source material means for hit dice representing both experience and size.
You'll still end up with a "GM modifier" for things like the giant baby, though. :)
Quote from: Steven Mitchell on September 25, 2020, 07:48:23 AM
Yeah. My issue is that I want the progression even flatter than that--that is, hit points less inflated overall. Like the OP, in a still very abstract system, I want to distinguish between adventuring toughness versus size toughness. Consider something like BEMCI, where a huge red dragon has 20d8 hit dice, or about 90 hit points. The dragon turtle hits that next step, coming in at 30d8 hit dice. However, dragons are a bad comparison, because getting bigger is a function of vast age, and is supposed to represent size and experience. Plus, that would be putting "huge" at the FS 21 mark.
Unlike all other editions, size in BECMI was never explicitly tied to age, IIRC. A big dragon can just be a big dragon.
But dragons are usually considered one of the toughest creatures in the game, for their size. So I'd use cat HD, or triple the numbers (at least). That would put a 15 HD dragon in the 5x5 category, and a 24 HD dragon in the 8x8 category.
Quote from: Steven Mitchell on September 22, 2020, 02:56:23 PM
Quote from: Zalman on September 22, 2020, 02:11:50 PM
Quote from: hedgehobbit on September 22, 2020, 01:38:47 PM
After d12 come 2d6, then 3d6, 4d6, etc. I haven't found much need for these except for Titans and older dragons.
Eh, so multiple dice-per-level? Aside from the fact that I personally find that aesthetically icky, the scale is a bit strange because it jumps up by 1hp on average until d12, then half a hp at 2d6, and then suddenly 3.5 additional hp at each size category thereafter. That's a tough one for me to swallow. I wonder if that scale could be done better and still kept as simple.
It might not be worth going to much effort there though, since meat dice seems pretty elegant.
For that kind of thing, I find that the Fibonacci Sequence gives me raw scaling that I like, but that it doesn't always align with dice code that well. Also, the standard sequence takes off really fast, at 2, 3, 5, 8, 13, 21, 34, 55, 89--not giving much room for multiple levels. (Starting at the technical beginning of the sequence doesn't help much, either.) What I've done instead is have the dice code hit every other level in the sequence, and then pick something in the middle that is close enough--with some judicious rounding for dice averages and a small modifier to handle not having much gaps in the early part of the sequence.
For example, let's use average dice, rounded up, with a flat modifier of +2 to the sequence. Putting a die code on every other sequence gives 4, 4, 5, 6, 7, 9, 10, 13, 15, 19, 23 (going up to 21 in the sequence where it starts to go crazy, though you could go 2 more results up to 34, 30 & 36 for really big creatures). Do a little judicious rounding down at the lower end to start at 1d4, 1d6, 1d10, 1d12, then start adding modifiers -- 1d12+2, +4, +6, +8, +12, +16, etc. After all, at the upper end of the scale, 2 extra points doesn't matter a lot.
The Fibonacci actually does turn into an exponential sequence if you take it far enough--the exponent is half (1+square root of 5), or about 1.618034. The number has the fun property of being 1 more than its reciprocal. The ratio is known as the 'golden mean' and wound up in Western art quite a few times. So it has a pedigree.
Quote from: Null42 on October 03, 2020, 08:31:19 AM
The Fibonacci actually does turn into an exponential sequence if you take it far enough--the exponent is half (1+square root of 5), or about 1.618034. The number has the fun property of being 1 more than its reciprocal. The ratio is known as the 'golden mean' and wound up in Western art quite a few times. So it has a pedigree.
It exhibits exponential growth, just not a consistent geometric progression. Because while it approaches the golden ratio, it never reaches it. Each step gives you a better approximation, tho.
From a game standpoint, that approximation can be useful because it's done with integers. That's why I was playing with it in a roguelike, where the basic unit is the (ASCII) character. The same could apply to any game using some kind of fixed-size tiles, or to minis on graph paper. It's less useful in games where you can size things freely, at high resolutions, like most computer games with modern graphics.