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View Full Version : Changing HD to CR in various spells and abilities



Kol Korran
2010-05-16, 09:35 AM
creatures of the same CR, and therefore the same threat level (i know the CR system is bad, suppose it was fixed)or the same "toughness". however, these varied creatures still have quite varied HD. and yet, many spells and powers refer to creature's HD, where i think it would make more sense to refer to a creature's CR.

prime examples for this are: Cleric's turn undead ability, polymorph, sleep, deep slumber, cloud kill, animate dead and planar ally spells. i'm sure there are quite a few more i'm missing at the moment.

do you think it is doable? do you think it would be a good idea? what would be the remifications? any serious problems you're seeing? i want to implement something of this sort for my next campaign, but would like to avoid the pitfalls.

thanks in advance. please discuss. :smallsmile:

Corlindale
2010-05-16, 09:55 AM
do you think it is doable? do you think it would be a good idea? what would be the remifications? any serious problems you're seeing? i want to implement something of this sort for my next campaign, but would like to avoid the pitfalls.

thanks in advance. please discuss.

My main problem with this would be that it doesn't really make sense to me. HD is a real property creatures have - it's an abstraction of sorts, yes, but it is still meant to be a measure of how "big and tough" something is. It makes sense within D&D logic that a creature with high HD can shake off a Color Spray more easily than one with low.

CR, by contrast, does not really "exist" in the world of D&D - it's sort of a meta-property. I don't think it would make much sense to tie CR to spell effects, since CR is really just something the GM uses as a reference, and not meant to be regarded as an actual property of creatures in my view.
Additionally, since CR is not a property of creatures as such, it is impossible for characters to estimate the effect that their spells is gonna have on the creatures, since it's impossible to "see" a creature's CR, whereas one might in some cases be able to roughly judge their HD by looking at them .

I'm not sure about the effects game-balance wise - you could glance through the monster manual to get an impression of it, perhaps.

Godskook
2010-05-16, 10:19 AM
Turn undead is a bad example, as Rebuke undead would become a lot more powerful at that point.(I can control twice my caster level in CRs of undead!)

sofawall
2010-05-16, 10:51 AM
Spells like Polymorph and Gate would have to change, otherwise it would just be hilarious. Gating in a CR 40 creature? Hello Umbral Blot!

awa
2010-05-16, 11:18 AM
on one hand your right it dosent directly relate to any real mensurable aspect of a creature but that dosent have to be the case you could just describe it has the creatures spiritual resistance that just happens to be equal to it's cr

Foryn Gilnith
2010-05-16, 11:37 AM
This would make it have no predictable basis in-universe, as it is now based on a pretty much unmeasurable factor.
I like that, actually. Makes these sorts of abilities more mystical and harder to pin down. The abilities that allow players to use MM resources, as earlier stated, would have to be heavily regulated. Those tend to cause problems.

Zeta Kai
2010-05-16, 01:00 PM
Challenge Ratings should never be part of the game's mechanics. They are a suggestion, & usually a questionable one at that. They are not based on any formula, or system, or anything logical. They do not even reflect an objective reality, because every party of characters is different. A CR10 monster may be a cakewalk for one team of 4 optimized characters, whereas it's a TPK for another group at the same level that are less optimized. Some monsters fit their CR very well, some are slightly weak, while others are too strong.

In short (TL;DR), replacing HD with CR is a Bad Idea.


This would make it have no predictable basis in-universe, as it is now based on a pretty much unmeasurable factor.
I like that, actually. Makes these sorts of abilities more mystical and harder to pin down. The abilities that allow players to use MM resources, as earlier stated, would have to be heavily regulated. Those tend to cause problems.

That might be true, but only in a perfect world where the players could never get their hands on the monster manuals. If they know the monster well enough to recall its ability is based off its HD, then they will know its CR, & your mysticism is moot.

Making this change will be a lot of work, for absolutely no benefit. To reiterate, basing your mechanics on somebody else's wild guess is a Bad Idea.

Kol Korran
2010-05-16, 01:14 PM
@ Godskook and sofawall: of course some powers and spells will have to be altered, to recieve basically the desired result. this idea takes some work. but do you think it might add to the balance of the game? i think it might actually give mroe sense to mechanics like turning and such. in one of our last meeting we fought a 20 hd skeleton. my cleric couldn't turn it, but could turn the controlling vampire, because it had less HD.

@ the rest: i think that CR is a very real D&D feature- it basically sets a hierarchy (though a very loose and inaccurate one) of who is tougher than who. true- it cannot always be estimated rightly, but that might be quite ok. just as you cannot estimate the level of an adventurer before it uses it's powers, so it might be hard to estimate a creature's CR before fighting it.

i disagree that there are no telltale signs- the carnage in a creature's lair, it's reputation, info gained from knowledge checks or sense motive ones (there is even a mechanic in the CoAd). i think that experienced adventurers, ones who make it their job to face such dangers, might well learn to estimate or even develop a general sense as to a creature's toughness.

EDIT: just saw Zeta Kai's post. i agree that CR is far from perfect. but i think it's far better than HD, which are an even more arbitrary game mechanic, even more problematic. to work out everything CR itself needs to be fixed, but that is larger than the scope i'm planning on.

(tl;dr): i think you can find a justification to estimation (accurate or less) of a creature's CR. if it improves balance and game mechanics it might be worth it. i do believe quite a bit of tweaking of said powers and spells is needed, but i think it would benefit the system. what do you think?

lsfreak
2010-05-16, 01:42 PM
My problem is that creatures don't have CR. Encounters do. A 'CR8 creature' CR6 when the party is prepared to face them, CR8 as a random encounter, CR9 when it's prepared for the party, and CR11 when the situation is perfectly to the creature's advantage and the PC's disadvantage.

Starbuck_II
2010-05-16, 01:49 PM
My main problem with this would be that it doesn't really make sense to me. HD is a real property creatures have - it's an abstraction of sorts, yes, but it is still meant to be a measure of how "big and tough" something is. It makes sense within D&D logic that a creature with high HD can shake off a Color Spray more easily than one with low.

CR, by contrast, does not really "exist" in the world of D&D - it's sort of a meta-property. I don't think it would make much sense to tie CR to spell effects, since CR is really just something the GM uses as a reference, and not meant to be regarded as an actual property of creatures in my view.
Additionally, since CR is not a property of creatures as such, it is impossible for characters to estimate the effect that their spells is gonna have on the creatures, since it's impossible to "see" a creature's CR, whereas one might in some cases be able to roughly judge their HD by looking at them .

I'm not sure about the effects game-balance wise - you could glance through the monster manual to get an impression of it, perhaps.

Untrue, CR is a real property as Truenamers use it for every non-PC effect.

Corlindale
2010-05-16, 02:19 PM
Untrue, CR is a real property as Truenamers use it for every non-PC effect.

I stand corrected. I didn't know about that - reading the DMG I always thought CR was just intended as an abstract measure of difficulty. Guess I was wrong :smallsmile:

PId6
2010-05-16, 02:34 PM
What I like about the idea of using CR rather than HD is that ideally it has a more predictable progression with character level. An ability like Truenaming, for example, is easier to calculate and balance when you can assume that a level 10 party will face CR 10 monsters. It's certainly not perfect, both in its previous execution (Truenamer) as well as in the CR system itself, but theoretically it's at least a better measure of what PCs will face than HD, which can vary wildly from creature to creature at any given level.

CR and HD are both abstractions; using one is only marginally more verisimilitude-breaking than the other. I don't see anything wrong with changing spells like Deep Slumber, for example, to function off of CR rather than HD, as long as you balance them in turn due to that change.

jindra34
2010-05-16, 02:42 PM
My problem is that creatures don't have CR. Encounters do. A 'CR8 creature' CR6 when the party is prepared to face them, CR8 as a random encounter, CR9 when it's prepared for the party, and CR11 when the situation is perfectly to the creature's advantage and the PC's disadvantage.

No creatures have CR, encounters have EL.

Godskook
2010-05-16, 03:16 PM
Untrue, CR is a real property as Truenamers use it for every non-PC effect.

Can we leave True-namers out of the balance discussion. Its like bringing up the joys of homicide at a peace conference.

PId6
2010-05-16, 03:51 PM
Can we leave True-namers out of the balance discussion. Its like bringing up the joys of homicide at a peace conference.
The point stands though. A system like Truenaming could never work if CR cannot be used mechanically, because it's the only quasi-accurate judge of the "relative power" of the enemies PCs will face at any given level. Scaling something like Truespeak DCs in accordance with HD just leaves you with wildly fluctuating DCs since the HD of monsters of similar power levels are not constant. (This isn't to say that Truenaming works in any way, shape, or form currently, or that the CR system doesn't wildly fluctuate in terms of monsters of a given power level, but in the ideal case it would make sense.)

Tehnar
2010-05-16, 04:11 PM
I think its a good idea that would solve a lot of HD based shenanigans.

While it may not be a "real" property of monsters, using it to calculate some "real" properties makes much more sense from a game balance perspective.

For example you can take a hill giant, advance it 8 giant HD and give it a void mind template. You get a utter brute at 9 CR (I think), mostly due to the fact that the void mind template gives abilities based on HD and not CR.

What you would avoid is cheating the HD - CR system, which I think is a good thing.

Zeta Kai
2010-05-16, 04:58 PM
The point stands though. A system like Truenaming could never work if CR cannot be used mechanically, because it's the only quasi-accurate judge of the "relative power" of the enemies PCs will face at any given level.

Bolded for emphasis. Anyone who knows anything about the Truenaming mechanics knows that they don't work. Period. And basing them off of CR is partially to blame.


i agree that CR is far from perfect. but i think it's far better than HD, which are an even more arbitrary game mechanic, even more problematic. to work out everything CR itself needs to be fixed, but that is larger than the scope i'm planning on.

HD is not arbitrary, it is the very foundation of what a monster's stat are. Almost everything about a monster's stats is generated based off of a combination of their ability scores & their HD. It is no more arbitrary than a creature's ability scores are. HD could arguably be called the Alpha Stat.

CR, meanwhile, is the opposite. It isn't tied to any specific mechanism of a creature's many other stats. It is merely a rough estimation of a creature's overall effectiveness, based on playtesting data that was gathered by people you don't know, using assumptions that you don't know. It affects almost no other mechanic in the game (except the afforemnetioned Truenaming, which speaks for itself), & cannot be derived until the creature's stats are complete & writ in stone; any single change of a creature's stats could have repercussions on its CR, no matter how small. It is, in effect, the Omega Stat.

Look, I can't tell you that you can't do what you are proposing. If you're hellbent on doing it, then more power to you, I guess. But I will tell you that I'm convinced that it's a Bad Idea. You will poor a lot of work into making it function, & in the end, you will have little, if anything, to show for it.

Godskook
2010-05-16, 05:26 PM
The point stands though. A system like Truenaming could never work if CR cannot be used mechanically, because it's the only quasi-accurate judge of the "relative power" of the enemies PCs will face at any given level. Scaling something like Truespeak DCs in accordance with HD just leaves you with wildly fluctuating DCs since the HD of monsters of similar power levels are not constant. (This isn't to say that Truenaming works in any way, shape, or form currently, or that the CR system doesn't wildly fluctuate in terms of monsters of a given power level, but in the ideal case it would make sense.)

So we really must bring up the joys of homicide here? Joy. Truenaming doesn't work even if you assume that CR is ok, and is entirely a separate issue to the CR/HD curve problem. Truenaming doesn't work for a lot of reasons, but being based off of CR instead of HD was actually a boon to the class, overall. Consider that 'underclocked' monsters who lack HD for their CR are rare, and typically, the discrepancy is minor(Such as a Pit Fiend's 18 HD and CR 20), while 'overclocked' monsters with too many HD are plentiful and utterly disparate(Dragons as a group, a lot of magical beasts, and every last 'advanced' monster in the book, since RHD is, at best, 1:2). Building the system off HD would've made truenamers easily screwed with. With the CR system, at least they can say: "Hey, if that's the DC, why the hell are you throwing that monster at us".

EnnPeeCee
2010-05-16, 06:06 PM
A creature's CR is based (partially) on the creature's abilities. If you base the creature's abilities on it's CR, you essentially make an "infinite loop".

Say you take an existing creature, and boost something on it to be dependent on the CR instead of the HD. Well now that creature is more powerful, and therefor, it deserves a higher CR. With a higher CR, its ability gets more powerful. The creature now deserves a higher CR based on the ability's increased power. Etc.

Of course this is only hypothetical, and it may taper off to a stable CR, or not change at all.

Just sayin'.

PId6
2010-05-16, 06:11 PM
Bolded for emphasis. Anyone who knows anything about the Truenaming mechanics knows that they don't work. Period. And basing them off of CR is partially to blame.
I've made it clear that Truenaming as written doesn't work. But that does not affect how a theoretical system, which uses a scaling check based on "monster toughness," similar to the Truenaming system but without the 2x stupidity, could work. Basing Truenaming checks on 2x CR is to blame; not basing it on CR itself. In contrast, basing it on HD would make it much worse, as Godskook had said above.

And there's no reason why a system like Truenaming, but with certain fixes, cannot work. I've heard good things about Kyuedo's Truenamer Fix (http://www.giantitp.com/forums/showthread.php?t=120488), which still uses CR (since HD is much harder to balance against) but has the check at DC 15 + (Utterance Level x 2) + Creature's CR. Still gets harder as the monster gets tougher, but at a reasonable progression as opposed to an impossible one.

And all of this is assuming a theoretical CR system that does do as it's supposed to. With a bit of work, such a system is not too hard to achieve. Yes, there are plenty of exceptions, and yes, plenty of monsters are underpowered or overpowered for their given CR. But overall, if you eliminate a few of the outliers, a monster with higher CR is probably more powerful than a monster with lower CR.


Truenaming doesn't work for a lot of reasons, but being based off of CR instead of HD was actually a boon to the class, overall. Consider that 'underclocked' monsters who lack HD for their CR are rare, and typically, the discrepancy is minor(Such as a Pit Fiend's 18 HD and CR 20), while 'overclocked' monsters with too many HD are plentiful and utterly disparate(Dragons as a group, a lot of magical beasts, and every last 'advanced' monster in the book, since RHD is, at best, 1:2). Building the system off HD would've made truenamers easily screwed with. With the CR system, at least they can say: "Hey, if that's the DC, why the hell are you throwing that monster at us".
That... is almost exactly my point. :smallconfused: Truespeak DCs and mechanics like it should be based off of CR rather than HD, because you can expect the CR of a typical monster you're going to face at level X being around X, whereas HD can be pretty much anywhere. It's much easier to balance for a level that you can expect than a level that you can't. I don't see a disagreement here.


A creature's CR is based (partially) on the creature's abilities. If you base the creature's abilities on it's CR, you essentially make an "infinite loop"..
Hence why you only base abilities on opponents' CR. A Deep Slumber spell that affects targets of CR 7 or less isn't going to lead to any infinite loops, for example.

Eldariel
2010-05-16, 06:43 PM
That... is almost exactly my point. :smallconfused: Truespeak DCs and mechanics like it should be based off of CR rather than HD, because you can expect the CR of a typical monster you're going to face at level X being around X, whereas HD can be pretty much anywhere. It's much easier to balance for a level that you can expect than a level that you can't. I don't see a disagreement here.

The disagreement here is that you should expect the DCs to be similar for monsters of similar CR. By default, higher HD monsters tend to be tougher, less powerful offensively/less versatile creatures and their HD is a part of that defense, so it just makes sense they're harder to affect than more offensive equivalents on the same CR.

Examples include Giants, which tend to be of much higher HD than their CR. Outsiders tend to be of about equivalent HD to their CR. Giants are comparatively tougher purely physically, while Outsiders have arrays of magical abilities that make them threatening with less HD. CR doesn't reflect this; it's mostly arbitrary and doesn't really model any in-game factor.


That and again, CR is unreliable. As written, power fluctuates wildly within CR making it unusable for a thing like this. If you want to derive such off CR rationally, you'll need to come up with a whole new measurable and count it individually for each creature, scrapping CR and at that point, there's really no reason to call it CR in the first place.

As written, CR is unusable for game mechanics due to unreliability, and should be divorced off them for that very reason. Also, CR doesn't represent any in-game ability but a metagame tool for a DM to determine encounter difficulty.

Kol Korran
2010-05-17, 04:03 AM
Eldariel and Zeta Kai make some interesting points. i'll need to think of this change some more... anyone else have any idea of how to change all the varied powers/ spells from using HD? i just find the reliance on HD very... crummy. (there is perhaps a better word, but i'm tired, and it reflects how i feel) :smallfrown:

awa
2010-05-17, 08:15 AM
i think it depends do you want it to be easier for a big dumb brute (giants, vermin, mindless undead) to be more easily affected by these kinds of spells then extremely deadly but less robust creatures (outsiders, creatures with class levels ect) if so cr is a decent way to do it theirs always going to be a gut instinct resisting anything diffrent

Kaiyanwang
2010-05-17, 09:55 AM
Just a nitpick: Truenamer is not alone in using CR mechanichally. Think about some PHII Knight challenges.

Elana
2010-05-17, 11:26 AM
With all the arguments against CR that were brought on so far..

What about using the HD modified by the level adjustment?

(After all WotC tried to tell us that would be the fair level to play such a thing)

Of course that would require some work to fit in a level adjustment for every creature as it would no longer just apply for playable races.
(which means of course races WotC considered playable)

Also it would probably help if the level adjustment was solely based on the abilities and not on how much WotC wanted players to discourage of playing the particular monster.



Hm, has anyone checked if pathfinder had fixed any of these issues?

Divide by Zero
2010-05-17, 11:35 AM
The point stands though. A system like Truenaming could never work if CR cannot be used mechanically, because it's the only quasi-accurate judge of the "relative power" of the enemies PCs will face at any given level. Scaling something like Truespeak DCs in accordance with HD just leaves you with wildly fluctuating DCs since the HD of monsters of similar power levels are not constant. (This isn't to say that Truenaming works in any way, shape, or form currently, or that the CR system doesn't wildly fluctuate in terms of monsters of a given power level, but in the ideal case it would make sense.)

And what would be wrong with that (assume for the moment that the Truenaming system worked at all)? Every class has more or less trouble with some types of creatures. Clerics have an easy time with undead, monks suck against fliers and incorporeals (more so than against everything else, anyway). In fact, it'd make Knowledge checks more useful by giving you an idea of which enemies would be most susceptible to your utterances.

sofawall
2010-05-17, 12:30 PM
Also it would probably help if the level adjustment was solely based on the abilities and not on how much WotC wanted players to discourage of playing the particular monster.

Well, just an example, Charm Person at will is much better for a PC than an NPC. Same for Greater Teleport (self plus 50 pounds) at will. I speak, or course, of the Succubus.

PId6
2010-05-17, 03:10 PM
And what would be wrong with that (assume for the moment that the Truenaming system worked at all)? Every class has more or less trouble with some types of creatures. Clerics have an easy time with undead, monks suck against fliers and incorporeals (more so than against everything else, anyway). In fact, it'd make Knowledge checks more useful by giving you an idea of which enemies would be most susceptible to your utterances.
If that were what you wanted as part of the design, then yes, that's perfectly fine. But if you, say, just wanted a flat ~25% failure on the check at all levels, easier on weaker enemies and harder on tougher ones, CR would be a better measuring stick than HD. It has specific uses, and you certainly don't need to use CR. I just think it's a valid tool to implement certain mechanics.

It's a bit verisimilitude-breaking since it's another layer of abstraction, but as long as you keep it to mechanics like magic, it's not hard to explain away and it can be very useful. After all, the characters don't know specifically how likely an utterance would affect an enemy; they just know that the more powerful the enemy, the less likely an utterance would work. It's the same as not knowing HP, saves, HD, skills, etc.

Eldariel
2010-05-17, 03:31 PM
If that were what you wanted as part of the design, then yes, that's perfectly fine. But if you, say, just wanted a flat ~25% failure on the check at all levels, easier on weaker enemies and harder on tougher ones, CR would be a better measuring stick than HD. It has specific uses, and you certainly don't need to use CR. I just think it's a valid tool to implement certain mechanics.

And that would be fine if CR wasn't erratic, all over the place and easier to just rewrite than fix. And a metagame consideration. What logic is there behind a big tough thing being easier to affect than its toughness would let one understand based on how big a challenge it's supposed to represent? And attack rolls or saves do the "certain difficulty to affect" just fine.

Godskook
2010-05-17, 03:35 PM
With all the arguments against CR that were brought on so far..

What about using the HD modified by the level adjustment?

Replacing HD with CR is making the number lower in almost all cases, and not doing much at all in the others.

Replacing HD with HD+LA makes the number higher in almost every case, which goes against the OP's intent, I'd imagine.

awa
2010-05-17, 06:21 PM
hd plus la of course is going to be higher then just la in many cases a lot higher their are very very few -la creatures or templates