GURPS monsters/NPCs in D&D, take two

[maximara]

Originally Posted by 2097

This was a li'l misunderstanding, but that's on me, because I wrote "it's not clear exactly how to do that" which I see now was ambiguous. It was read as "it's not clear exactly how to do that" when I meant "it's not clear exactly how to do that".

It's not exactly clear how to use a GURPS book as a supplement for another game. I think I have some pretty good ideas now on how to do that.

This is because there are several ways to use a GURPS book. For example,

"Power Investiture also allows GMs a method of actually using ideas suggested in several Dragon #92 articles and addressed again in Dragon #101. The basic premise of the articles was that the power a deity has in a particular area (represented in GURPS by the sanctity level) is proportional to the amount of belief there is for the deity."

GURPS Religion give you the tools to build your own cosmology and a way to fine tune how Clerics work.

Originally Posted by 2097

It's easier to convert from something detailed (like GURPS) to something simple (like D&D) than the other way around.

To some degree that is true but that simplicity comes at a cost. Is that "holy warrior" actually a Paladin channeling the power of their deity, a cleric channeling the power of their deity, or a fighter fighting on behalf of the deity?

Alignment is the best sample of how that simplicity can turn into a convoluted mess. Evil alignment in older versions of D&D feels more like the type of evil you read in comic books or seen in most cartoons. As the saying goes 'a villain is the hero of their own story'.

"No wonder characters who take on evil personae find themselves appalled by their own behavior. So would anyone who set out to be the opposite of what they knew was right and good. Even the most “evil” villains of history did not have the sort of attitude that an assassin character is expected to have..." - For King and Country Dragon #101 (Sept 1985)

Originally Posted by 2097

That's already similar to how the new D&D works. Like the Thug I used as an example earlier has Mace +4 (the equivalent of Mace-12) and Crossbow +2 (the equivalent of Crossbow-11).

For an all GURPS-example, it's also kinda similar to how wildcard skills work or how classes work in GURPS Ultra-Lite.

Uh there are no "classes" in GURPS Ultra-Lite, but what amount to wildcards:

"To be better at tasks, you can put some of your levels into skills. Skills go with professions the GM allows on this adventure – Crook, Knight, Ninja, etc. Each skill has four levels; each level gives +4 for its tasks. Note level and bonus; e.g., Crook 2 (+8)."

Today it would be more accurately "Crook!, Knight!, Ninja!, etc"

Also you do know that GURPS Ultra-Lite was a work in progress (version 0.8) that hasn't seen an update since 2009, right?

Originally Posted by 2097

I don't know what Unkillable is.

From D&D to GURPS page on the GURPSwiki :
Unkillable

Nearly every high level Undead monster and many demons in D&D will have this advantage. Unkillable 1 allows the monster to remain fighting all the way to -10*HP without a single HT roll and Unkillable 2 and 3 allow the thing to come back! Dracula in the Hammer horror films had Unkillable 3 with the Achilles Heel (wood, running water), Hindrance (wood, frozen water), Trigger (blood) limitations.

[Phoenix_Dragon]

I don't think you'll be able to boil it down to a simple formula like you're trying to do. Certainly not this formula. I decided to sanity-check it with a character in my current campaign and it really didn't work.

The character in question is a large, anthropomorphic beetle warrior, who uses her four arms to wield a two-handed weapon and a shield at the same time. At a bit over 200 points (Which is likely around level 5 to maaaybe 10 in D&D 5e, and still below a starting character in GURPS Dungeon Fantasy), she has ST16 (High, but quite reasonable), DX12, IQ 10, HT12, a primary weapon skill of 16, and a shield skill of 18. This also means 16 HP and 12 FP. Between her natural carapace and the armor that she's put almost all of her adventuring money into, she has DR9 over much of her body (Which is pretty good, but hardly the best, especially compared to magical armor). I picked her because she is the most straightforward character in the group for conversion purposes: she is a straight-up fighter.

So how does the formula do?

HP + FP = 28. 28/4 = 7, so we add 7 times DR to that. She gets 91 HP. From the attribute formula below, she would have a Con bonus of +4, and a fighter who focused on getting their Con up to +4 would expect to hit 91 HP at around level 9 (A 9th level fighter with Con +4 and no HP-related feats would have an average of 90 HP if rolling, or exactly 94 HP if taking the fixed amount per level). This is one of the few places the formula gives a reasonable result. Though it's worth noting that if you remove her armor, then she only gets 56 HP, about what you'd expect for a 5th level fighter.

For attributes: ST 16 in GURPS becomes a +12 Str mod in D&D, or Str 34. This would mean that she is stronger than a Tarrasque, if not for the fact that an ability score that high is literally impossible (By the rules, she can be at most as strong as a Tarrasque).

She also gets Dex 20 (Despite being only "above average" in GURPS), Con 20 (She's tough, but not that tough), and Cha 20 (Making her among the most charismatic people in the world, despite actually being kind of quite, reserved, and a little socially awkward). Int 10 and Wis 10 are the only ones that seem reasonable here.

Damage: Well, her main weapon is a mundane dueling-length halberd, so 1d10+12, which is well above what a fighter would be rolling without serious magic. But a D&D fighter also gets multiple attacks; she, being a fighter-type, presumably would as well, but this conversion gives no guidelines for that, despite it making such a huge difference in damage output. Assuming she gets the same extra attacks as any other fighter, her damage output is well above what it should be. If she doesn't, it's well below where it should be.

To hit: A weapon skill of 16 converts to +12. This means she can wield her weapon better than a 20th level fighter in the same equipment. It also has a pretty disastrous implication: Since her weapon is a Str weapon, and her Str bonus itself is +12, this would mean she has a proficiency bonus of +0. That's below the minimum possible, and certainly doesn't represent someone who is, in GURPS terms, an expert at using a halberd.

AC: With a shield skill of 18, that would give an AC of 26, which is technically possible for a fighter with plate armor and a shield, but only with tens if not hundreds of thousands of GP in magical equipment, with the cheapest of those options also requiring two of your three attunements. And she does this while wearing the equivalent of D&D "chain mail." Except she can remove her armor, go completely naked, and still have an AC of 26. 22 if she ditches the shield (Which is still above what's possible for a fighter with any armor that isn't magical).

And then there are some strange gaps where important traits end up doing nothing. Being a warrior type, she has Combat Reflexes, which in GURPS gives her a bonus to defense as well as being much harder to catch off-guard. With these formulas, it does absolutely nothing. No bonus HP (Which, in D&D, includes things like luck and reflexes). No bonus AC. Nothing.

The formulas really don't work for her, and she's really not an extreme case. ST16 is not too unusual for strength-focused fighter-types, and the DR, while high, is not even remotely the most extreme that it could be. She doesn't have any of the DR enchantments that some other members of the party have (One has DR 6 when completely naked), and doesn't use any fortify potions that the alchemist could easily brew up.

It really breaks on anything that has above-average ST in GURPS, and that's especially apparent if we compare animals that have stats in both systems. Consider the brown/grizzly bear. GURPS gives it ST 19. D&D gives it Str 19 (+4). But the conversion from GURPS to D&D gives it a Str mod of +12, three times higher than it should be. It also gives a Con mod of +6 (Twice what it should be), a Cha mod of +6 (8 higher than it should be!), and a Wis mod of -8 (9 less than it should be). It also gets 48 HP (About 50% higher than it should have), and going off its brawling skill, an AC of 16 (5 higher than it should be). Basically anything or anyone who has more than 12 in any attribute is going to produce extreme (And sometimes impossible) results. Like the bookish alchemist of the group who started, at 150 points, with an IQ that would convert to Int 30 and Wis 30. Half the group started with weapon skills that would convert to to-hit bonuses a D&D character wouldn't see without magic until 17th level, if ever. Some inaccuracy is expected, since conversion will always be a messy prospect, but this seems to produce results that can be so far off that I suspect it'll cause far more problems than it will solve.

For characters, you're almost certainly better off looking at their general power level, interpreting that as a certain level in D&D, and then building a D&D character of that level that aims for the same flavor. For monsters, you're probably better off comparing their capabilities and power to existing creatures and just giving them similar scores. It's possible that you might be able to work out a formula for this... but it's not this one. And one that's more reasonable is going to need to be more complex, so that moderate levels of attributes give a wide range without the higher (Or lower!) ranges producing such extreme results. I'm thinking fractional exponents or creative division would need to be applied.

[maximara]

Originally Posted by Phoenix_Dragon

I don't think you'll be able to boil it down to a simple formula like you're trying to do. Certainly not this formula. I decided to sanity-check it with a character in my current campaign and it really didn't work.

That was my gut feeling and glad to see you confirm it. Using a formula to go from D&D to GURPS always turned into a disaster so it logically followed the reverse was also true. But, boy I wasn't expecting this formula to be that much of a disaster.

Originally Posted by Phoenix_Dragon

It really breaks on anything that has above-average ST in GURPS, and that's especially apparent if we compare animals that have stats in both systems. Consider the brown/grizzly bear. GURPS gives it ST 19. D&D gives it Str 19 (+4). But the conversion from GURPS to D&D gives it a Str mod of +12, three times higher than it should be. It also gives a Con mod of +6 (Twice what it should be), a Cha mod of +6 (8 higher than it should be!), and a Wis mod of -8 (9 less than it should be). It also gets 48 HP (About 50% higher than it should have), and going off its brawling skill, an AC of 16 (5 higher than it should be). Basically anything or anyone who has more than 12 in any attribute is going to produce extreme (And sometimes impossible) results. Like the bookish alchemist of the group who started, at 150 points, with an IQ that would convert to Int 30 and Wis 30. Half the group started with weapon skills that would convert to to-hit bonuses a D&D character wouldn't see without magic until 17th level, if ever. Some inaccuracy is expected, since conversion will always be a messy prospect, but this seems to produce results that can be so far off that I suspect it'll cause far more problems than it will solve.

Just, wow. And I thought the comparison of Dai Blackthorn to a AD&D1 thief was resulted in off the wall bonkers results demonstrated how even using odds to convert between the two systems was "a very bad idea".

As I said before going from D&D to GURPS is reasonally easy but doing the reverse is problematic...and that was because I was looking at a method that covered everything but D&D4. And here I thought letting a party of 100 pt characters loose in the Tomb of Horrors produced some wonky results.

[2097]

Maximara, what are you trying to do here? Just put me down or prove some kinda point, win some kinda debate?
If the latter, what even are the positions?

I just wanna have some fun with all the new GURPS books I bought♥
And enjoy them in our campaign♥

Originally Posted by Phoenix_Dragon

I don't think you'll be able to boil it down to a simple formula like you're trying to do. Certainly not this formula. I decided to sanity-check it with a character in my current campaign and it really didn't work.

Thank you for putting some eyeballs on this thing, Phoenix_Dragon, much appreciated.

Originally Posted by Phoenix_Dragon

The character in question is a large, anthropomorphic beetle warrior, who uses her four arms to wield a two-handed weapon and a shield at the same time.

First of all: That is baller. Congrats making her♥

Originally Posted by Phoenix_Dragon

At a bit over 200 points (Which is likely around level 5 to maaaybe 10 in D&D 5e, and still below a starting character in GURPS Dungeon Fantasy),

Mapping character points to levels is not something that my formula tries to do.

Originally Posted by Phoenix_Dragon

she has ST16 (High, but quite reasonable),

So a 3d6 roll on 16 (I know that you usually don't roll straight ST, but bear with me) succeeds 98.15 of the time. (That's why you usually sink things into Deceptive Attack or other special moves on GURPS.)

A d20+X vs the medium DC 15, the highest you can get is 95% of the time which would be +14, but I like sticking with the cap of +12 to make the player characters have some chance :)

Originally Posted by Phoenix_Dragon

DX12, IQ 10, HT12, a primary weapon skill of 16, and a shield skill of 18. This also means 16 HP and 12 FP. Between her natural carapace and the armor that she's put almost all of her adventuring money into, she has DR9 over much of her body (Which is pretty good, but hardly the best, especially compared to magical armor). I picked her because she is the most straightforward character in the group for conversion purposes: she is a straight-up fighter.

So how does the formula do?

HP + FP = 28. 28/4 = 7, so we add 7 times DR to that. She gets 91 HP.

Right♥

Originally Posted by Phoenix_Dragon

From the attribute formula below, she would have a Con bonus of +4, and a fighter who focused on getting their Con up to +4 would expect to hit 91 HP at around level 9 (A 9th level fighter with Con +4 and no HP-related feats would have an average of 90 HP if rolling, or exactly 94 HP if taking the fixed amount per level). This is one of the few places the formula gives a reasonable result. Though it's worth noting that if you remove her armor, then she only gets 56 HP, about what you'd expect for a 5th level fighter.

OK, so it's part natural carapace and part armor for her? She sounds cool♥

Originally Posted by Phoenix_Dragon

For attributes: ST 16 in GURPS becomes a +12 Str mod in D&D, or Str 34. This would mean that she is stronger than a Tarrasque, if not for the fact that an ability score that high is literally impossible (By the rules, she can be at most as strong as a Tarrasque).

That's the life-changing magic of bell curves at work.

Originally Posted by Phoenix_Dragon

She also gets Dex 20 (Despite being only "above average" in GURPS), Con 20 (She's tough, but not that tough), and Cha 20 (Making her among the most charismatic people in the world, despite actually being kind of quite, reserved, and a little socially awkward). Int 10 and Wis 10 are the only ones that seem reasonable here.

I think this isn't quite right. She has DX 12 so that would be a mod of +4.

Rolling under 12 on 3d6 succeeds 75% of the time. So +4 isn't high for that at all vs DC 15.

Remember that in 5e D&D they also have proficiency bonus, and this formula "bakes that in" instead of also adding it it later.

So a +3 proficiency bonus character (like a level 5 would have) that has Dexterity 12 would have +4. One from the ability and three from the proficiency.

Originally Posted by Phoenix_Dragon

Damage: Well, her main weapon is a mundane dueling-length halberd, so 1d10+12, which is well above what a fighter would be rolling without serious magic. But a D&D fighter also gets multiple attacks; she, being a fighter-type, presumably would as well, but this conversion gives no guidelines for that, despite it making such a huge difference in damage output. Assuming she gets the same extra attacks as any other fighter, her damage output is well above what it should be. If she doesn't, it's well below where it should be.

It's a little below for a fighter but this isn't meant for the PCs, it's meant for people they can meet in the game world, maybe fight, maybe become friends with, it's up to them.

Originally Posted by Phoenix_Dragon

To hit: A weapon skill of 16 converts to +12. This means she can wield her weapon better than a 20th level fighter in the same equipment. It also has a pretty disastrous implication: Since her weapon is a Str weapon, and her Str bonus itself is +12, this would mean she has a proficiency bonus of +0. That's below the minimum possible, and certainly doesn't represent someone who is, in GURPS terms, an expert at using a halberd.

I think of it as "the sum of her proficiency bonus and her Str bonus is +12." The exact breakdown of those two is unknown.

Originally Posted by Phoenix_Dragon

AC: With a shield skill of 18, that would give an AC of 26, which is technically possible for a fighter with plate armor and a shield, but only with tens if not hundreds of thousands of GP in magical equipment, with the cheapest of those options also requiring two of your three attunements. And she does this while wearing the equivalent of D&D "chain mail." Except she can remove her armor, go completely naked, and still have an AC of 26. 22 if she ditches the shield (Which is still above what's possible for a fighter with any armor that isn't magical).

The AC is also capped at 22. I should edit the post to make that clear. Thank you.

Originally Posted by Phoenix_Dragon

And then there are some strange gaps where important traits end up doing nothing. Being a warrior type, she has Combat Reflexes, which in GURPS gives her a bonus to defense as well as being much harder to catch off-guard. With these formulas, it does absolutely nothing. No bonus HP (Which, in D&D, includes things like luck and reflexes). No bonus AC. Nothing.

Right, I haven't looked at most advantages so far. I don't want to exhaustively look up every advantage, but a short list of the most important ones could be fine. In this case she is already so near the cap.

So what we have here is an AC 22, HP 91, +12 to hit for 1d6+12 with my formula or 2d6+7 using the GURPS standard damage [ST 16 /w sw+5, right?] character. Weak saves so Charm and Fear spells would work well on her.
Looking in the DMG p274, her defensive CR and her offensive CR both work out to 8 so she looks fine in that regard. A CR eight creature. Similar to this assassin NPC stat block. I'm happy with that, she's cool and she makes sense to be on there.

Now, fighting her… Let's say I'm a level 8 D&D hero and I have a +8 attack bonus (from +5 ability after a few ASIs and +3 prof) and I attack with a 1d8+5 weapon. It'd take me… Let's see… Around 27 attacks! That's a long fight, almost four rounds if we are four people going up against her. Compared to the assassin stat who would go down twice as quickly.

Let's also check if she were fighting herself with a +12 attack for 1d6+12. She'd need a little bit over 11 attacks to defeat her clone. Still a long fight, same as me vs the assassin.

Now let's see how many attacks it'd be in GURPS. She has DR 9 so I'd need to roll over 9 damage to even hit her, that's how DR works, right? And she defends at, shield skill 18 that's a block of 12 (18/2+3, right?).

For the clone fight (weapon skill and str both at 16) that means the attacking clone gets the 2d6+7. She has a 25% chance of getting through her clone's carapace, that's pretty good! EV of 4 attacks before first blood, and around 27 attacks to bring her clone down to -16 HP.

Let's say I have my own 14 weapon skill and a weaker 1d6+5 weapon. That's still an almost 12% chance of hurting her. EV of 9 attacks before she takes any (GURPS) HP loss. Then I accidentally put in 1d6+6 and it took me around 330 attacks and when I remembered that it was 1d6+5 I just couldn't do it! My computer timed out. I mean it has to be hundreds and hundreds of attacks? That's why people need Deceptive Attack I guess!

This tells me that she is a pretty good port! She takes a long time to fight but she takes even longer to fight in GURPS.

Now, usually in 5e it's more fun to fight creatures that have a li'l bit less AC so I could tweak the formula to match that design goal. Maybe lower AC but more HP, I don't know…
(cont'd)

[2097]

Originally Posted by Phoenix_Dragon

It really breaks on anything that has above-average ST in GURPS, and that's especially apparent if we compare animals that have stats in both systems. Consider the brown/grizzly bear. GURPS gives it ST 19. D&D gives it Str 19 (+4). But the conversion from GURPS to D&D gives it a Str mod of +12, three times higher than it should be. It also gives a Con mod of +6 (Twice what it should be), a Cha mod of +6 (8 higher than it should be!), and a Wis mod of -8 (9 less than it should be). It also gets 48 HP (About 50% higher than it should have), and going off its brawling skill, an AC of 16 (5 higher than it should be).

Where are GURPS stats for the brown bear, please? Wis mod of -8 indicates that its GURPS perception is 6. (Or did you find another mistake—that I should've explicitly written perception instead of IQ? Thank you♥)

Originally Posted by Phoenix_Dragon

Basically anything or anyone who has more than 12 in any attribute is going to produce extreme (And sometimes impossible) results. Like the bookish alchemist of the group who started, at 150 points, with an IQ that would convert to Int 30 and Wis 30. Half the group started with weapon skills that would convert to to-hit bonuses a D&D character wouldn't see without magic until 17th level, if ever. Some inaccuracy is expected, since conversion will always be a messy prospect, but this seems to produce results that can be so far off that I suspect it'll cause far more problems than it will solve.

My original attempt a few years ago didn't do the doubling. My aim there was to get something that was fun to play in D&D without necessarily matching the GURPS match; I would get varied characters, like a IQ 12 would get +2 and an IQ 13 would get +3 making the second slightly better than the former. But IQ +3 in D&D is 5 percent better than +2. IQ 13 in GURPS is 10% better than 12.

You are doing something that I don't really do: you do the subtract ten and double, which is great, but then you convert back to what D&D score would've produced that. IQ 12 = +4 (so far so good) so that must mean D&D Int 18? Not necessarily. A starting 5e character starts with +5 in their good skills. Three from the best ability and two from the proficiency. So it's more like an Int 16 character which you can get free from the standard array or are 80% likely to roll if you're rolling.

I'm not trying to create the full character with all her attributes, all her multiple-attacks-per-round fighter-class stuff. This isn't for converting PCs. It's for converting monsters and NPCs. Foes and friends.

I'm just trying to see what her chances are of landing an attack, of blocking an attack, and of surviving non-blocked attacks and match those. And for the beetle fighter all those three things matched up well.

As a defensive CR 8, she'd be more fun to fight with AC cranked down to something like 16 (and having around twice the HP to compensate). But, Shield-18 in GURPS is really high.

[2097]

Originally Posted by maximara

That was my gut feeling and glad to see you confirm it. Using a formula to go from D&D to GURPS always turned into a disaster so it logically followed the reverse was also true.

Going from something abstracted to something more detailed is something that's difficult to do with a formula. But the other way around might be possible, which is my hope here.

Originally Posted by maximara

But, boy I wasn't expecting this formula to be that much of a disaster.

Come on, I feel like you're picking on me for the sake of picking on me. It's hurtful. I'm not trying to win a fight here. I'm not in competition with you or a threat to you in any way.

Originally Posted by maximara

Uh there are no "classes" in GURPS Ultra-Lite

You're right, I accidentally called the professions in GURPS Ultra-Lite "classes".

Originally Posted by maximara

but what amount to wildcards [...] Today it would be more accurately "Crook!, Knight!, Ninja!, etc"

That's not contradicting anything I wrote. (It came out after wildcard skills came out and still didn't have the bangs, though. "Profession skills" work similarly to how wildcard skills work, which is what I tried to say except I called it classes.)

Originally Posted by maximara

Also you do know that GURPS Ultra-Lite was a work in progress (version 0.8) that hasn't seen an update since 2009, right?

I know. I like it a lot, though.

GURPS Ultra-Lite a great way to make characters for GURPS, especially NPCs; the combat system in Ultra-Lite doesn't work.

[maximara]

Originally Posted by 2097

Where are GURPS stats for the brown bear, please? Wis mod of -8 indicates that its GURPS perception is 6. (Or did you find another mistake—that I should've explicitly written perception instead of IQ? Thank you♥)

Animals are generally handled as statblocks (Just the stats, mam :-))

While, AFAIK, the Brown Bear isn't stated out in 4e the Black, Grizzly, Polar, and Cave Bears have been (Bestiary, Basic Set)

They all have Per 10 and Will 11, except for the Black Bear with Will 12. IQ is of course 4.

Castle Everglory shows these statblocks with various monsters.

[Phoenix_Dragon]

Originally Posted by 2097

First of all: That is baller. Congrats making her♥

Thanks! She's fun.

Mapping character points to levels is not something that my formula tries to do.

I was including that only for illustrative purposes of what would constitute a reasonably experiences and somewhat exceptional fighter, but one who's still well short of legendary status or facing world-changing threats. If a fighter falls into that category in one game, you'd think a good conversion would put them at the same power level. One that puts them in a completely different category of power has some problems.

So a 3d6 roll on 16 (I know that you usually don't roll straight ST, but bear with me) succeeds 98.15 of the time. (That's why you usually sink things into Deceptive Attack or other special moves on GURPS.)

Ah. I see why the formula is producing such bizarre results. You're looking to match chance of success in games that have dramatically different mechanical expectations for these things, which is going to produce very screwy results when you then try to cross them over into another game without accounting for this.

You can't just flat-map the bell-curve success chance to the d20 roll chance and get sensible results. The mechanics and assumptions are too different. Comparing two characters without magic items: In GURPS, an expert at a skill (Say, skill 15) will succeed at an average task 95% of the time, while a master (Skill 20+) would succeed at a pretty hard task (-5 or more) at that same rate. In D&D, a 20th level character with maxed out stat of 20 (+5) and using a skill he's proficient in succeeds on that DC15 Medium difficulty roll only 80% of the time, despite being at the peak of mortal ability; against even a Hard difficulty of DC20, his odds drop to just 55%.

D&D is mechanically built to assume a skilled character will fail more often than GURPS does. Any conversion really needs to keep that in mind.

I think this isn't quite right. She has DX 12 so that would be a mod of +4.

You're right. I'm not sure why I was thinking +4 was 20 instead of 18. Still, that means her stats are three 18s, two 10s... and an impossible 34. If I handed that character to any DM, I'm pretty sure they'd reject it outright. Some might even start looking for the lighter fluid.

Rolling under 12 on 3d6 succeeds 75% of the time. So +4 isn't high for that at all vs DC 15.

In GURPS, DX12 is merely above average. In D&D, Dex 18 is only just shy of peak human physical performance. If that's not bad enough, it's worth noting that these stats were from several sessions ago. She now has DX13 (Which is notable and easily recognizable, but still well short of "amazing" and easily achievable for regular humans), but your conversion would give her D&D Dex of 22, which is outright beyond what is humanly possible.

I think of it as "the sum of her proficiency bonus and her Str bonus is +12." The exact breakdown of those two is unknown.

That's what I was assuming, and why I pointed it out as a problem. If her to-hit is a combination of Str bonus and proficiency, the to-hit is +12, and her Str bonus is +12, then her proficiency bonus would have to be +0. It's also above what a human fighter could ever reach without magic (Which would presumably benefit her, as well).

The AC is also capped at 22. I should edit the post to make that clear. Thank you.

That just makes things more weird. I mean, she still has a better AC than a fighter could possibly get without magic, though it brought down the expense a good deal. The problem is, she now gets that completely naked and without her shield. Her shield does her no good. And the armor only gives HP instead of AC.

Right, I haven't looked at most advantages so far. I don't want to exhaustively look up every advantage, but a short list of the most important ones could be fine. In this case she is already so near the cap.

Combat Reflexes is kind of an important one. It's a big chunk of points and quite valuable, especially to any fighter types.

So what we have here is an AC 22, HP 91, +12 to hit for 1d6+12 with my formula or 2d6+7 using the GURPS standard damage [ST 16 /w sw+5, right?] character. Weak saves so Charm and Fear spells would work well on her.

Sw+4. She's using a dueling halberd. Against armor she'd probably use the back-spike (sw+3 imp) to avoid the edge-protection rules, but D&D doesn't even allow piercing damage from a halberd, much less anything like the edge-protection rules.

Looking in the DMG p274, her defensive CR and her offensive CR both work out to 8 so she looks fine in that regard.

That's not what I'm getting. For Defensive CR, I see 91 HP gives CR2. CR2 expects AC 13, and 22 is 9 higher than that, so +4 to CR; final Defensive CR is 6.

For Offensive CR, damage output is 15.5 (1d6+12), so either CR 2 again. CR 2 expects an attack bonus of +3, and +12 is 9 higher than that, so +4; final Offensive CR 6.

Either way, rounding puts her at CR 6. Even if we allow fractional CR when calculating the bonus for AC or attack bonus (Which doesn't seem to be the case), then we get CR 6.5, rounded up to 7.

But I think looking at those tables reveal just how strange the conversion is. Her HP and damage output are extremely low, and her effective CR is only boosted up because your formula gave her a legendary-level to-hit bonus and an AC that is literally beyond what the table covers.

Perhaps more importantly, you're taking what is a reasonably experienced and capable low-mid level character, and converting her in a way that claims she is a reasonable challenge for four reasonably experienced and capable low-mid level characters.

Now let's see how many attacks it'd be in GURPS. She has DR 9 so I'd need to roll over 9 damage to even hit her, that's how DR works, right?

Yes, which with her damage output (2d+6 max), means her DR has a 3/36 chance of stopping her own attack (About 8%).

And she defends at, shield skill 18 that's a block of 12 (18/2+3, right?).

It's a large shield, so DB+3. Plus Combat Reflexes. Her block is 16. Her parry is 15 (16 if she's in defensive grip).

For the clone fight (weapon skill and str both at 16) that means the attacking clone gets the 2d6+7. She has a 25% chance of getting through her clone's carapace, that's pretty good! EV of 4 attacks before first blood, and around 27 attacks to bring her clone down to -16 HP.

Without Deceptive Attack, she has a 98% chance to hit, vs a 98% chance to block, for just under 2%, or one hit per 50 attacks. Her chance to hit would be dominated by the ~9% chance to critically hit, or one hit per ~11 attacks. With full Deceptive Attack (-6), she has a 50% chance to hit, vs a 84% chance to block (Assuming no other defensive tricks like retreat), for an 8% chance to hit, or about one hit per 13 attacks. So lets go without Deceptive Attack for simplicity.

On a hit, 2d6+6 vs DR9 is complicated. I'm feeling too lazy to work out the exact actual average (The non-penetrating hits complicate it), so let's just go with the average roll: the average roll of 2d6+6 is 13, 4 damage penetrates, inflicting 6 HP of injury. We'll ignore the effects of critical hits, because most of them won't actually increase damage (And I'll note, we're ignoring critical successes on block, too). Going from 16 to -16 HP requires 32 damage, which is 6 average injuries. Except the fight probably ends shortly after we get her down to 0 HP to start rolling for consciousness.

So we're looking at somewhere around 60 attacks if they're just whacking away at each other like a D&D fight. Around 30 attacks to get the clone below 0 HP.

But if we're looking at clone fights, let's look at what she'd do in D&D with your conversion. +12 to-hit vs AC22 means a 55% hit rate. It would take 6 hits to bring her down, so around 11 attacks.

Let's say I have my own 14 weapon skill and a weaker 1d6+5 weapon. That's still an almost 12% chance of hurting her.

Skill 14 vs Block 16 is a 2% chance of landing a hit (And 9% chance of suffering a critical failure due to a critical success of block, but we'll ignore that). If you go full Deceptive Attack, that would bump you up to 5% (And drop critical block chance to just 2%). On a hit, you have only a 50% chance of inflicting any injury. Your average damage per attack will be 1 point of damage ((0 + 0 + 0 + 1 + 2 + 3) / 6 = 1), for 1.5 injury (Assuming cutting). So your reasonably skilled fighter making Deceptive Attacks would do an average of 1.5 injury per 20 attacks, or about 500 turns of whacking away at her to get her to -16 HP (Though good news, you probably only need to get her to 0 HP or less, so you're really done in about 250).

You would also expect to suffer about a half dozen critical blocks. If you didn't use Deceptive Attacks, then you're looking at more like 25 times you need to find and pick up your weapon.

Except GURPS combats don't work that straight-forward. People love to do flat-empty-plane simulations like this, but I can tell you from experience in my campaign, it never goes that smoothly. You've got feints and beats and tricks. You've got multiple attacks. You've got one person baiting out the good defense so another can slip a hit in. You've got terrain that makes some tactics better or worse. Shields can get beaten up and destroyed. You've got attacks to other locations. You've got chinks in armor. She was built to be as tanky and defensive as possible, and clearly outpaces the entire rest of the group for defenses, but it's not nearly as perfect as you might think from this. She's probably taken more damage than anyone else in the group.
(Continued...)

[Phoenix_Dragon]

Originally Posted by 2097

Where are GURPS stats for the brown bear, please? Wis mod of -8 indicates that its GURPS perception is 6. (Or did you find another mistake—that I should've explicitly written perception instead of IQ? Thank you♥)

GURPS has the North American Brown Bear (AKA, the grizzly) in Campaigns, pg 456.

And yes, Per instead of IQ is kind of an important thing to explicitly write out, because they can be very different. Unfortunately, it doesn't help the rest of the attributes. Like Int being negative (Not the bonus, which would be -8. The actual score, which would have to be something like -6 to get a modifier of -8, and which is again outside the possible range of attributes in D&D).

You are doing something that I don't really do: you do the subtract ten and double, which is great, but then you convert back to what D&D score would've produced that. IQ 12 = +4 (so far so good) so that must mean D&D Int 18? Not necessarily. A starting 5e character starts with +5 in their good skills. Three from the best ability and two from the proficiency. So it's more like an Int 16 character which you can get free from the standard array or are 80% likely to roll if you're rolling.

You might want to update your formulas, then, because that's not what it says. It says they're calculating the ability modifiers, which are tied explicitly to the ability scores that produce them. What you're talking about now is ability modifier plus proficiency bonus, which is not the same thing as just ability modifier.

Also, it kinda makes the situation worse. A D&D character only gets their proficiency bonus in skills that they're proficient in, which is only a small selection of the total skills available. This formula essentially gives very broad capability that isn't related to their skills in GURPS. For instance, some stealth-oriented characters in GURPS might be DX 12 with 20 in stealth, or DX 16 with 16 in stealth; your conversion gives the first, master-level sneak only +4 for stealth (Pretty bad for even a 1st level rogue!), while the second, good but much less sneaky one, has +12 (Decent for a mid/high-level Rogue that puts expertise in stealth, and impossible for almost anyone else).

I'm just trying to see what her chances are of landing an attack, of blocking an attack, and of surviving non-blocked attacks and match those. And for the beetle fighter all those three things matched up well.

While trying to match chance-of-success across vastly different mechanical schemes is a bad way of doing it, I don't think you managed to achieve even this.

Her chances of landing an attack in GURPS, against a combatant of high skill (Say, 16, but no shield), is about 25% (And she has many ways of boosting this much higher!). Against a combatant in D&D, of any skill, your formula gives her odds ranging from 75% (Against plate, no shield) to 95% (Against anything AC14 or less.

Defensively, that 8th level fighter you mentioned would have a 35% chance of hitting her with normal attacks. In GURPS, a same-skill fighter would land only 9% of his attacks.

Combine the two for a clone fight, and she goes from landing 9% of attacks in GURPS to 55% of attacks in D&D.

For surviving landing hits, in GURPS, she would be able to put her clone to <0 HP in 3 hits, at which point the clone is rolling to stay conscious and can expect to go down in a few seconds. 6 hits would put the clone to full -1xHP and checking for death. In D&D, she'd need 6 average hits for the clone to go down at all, which is double where the fight would probably end in GURPS, and there is no margin between "incapacitated" and "might die." This is the only one that gets even close, and only if you aim for different results. Nevermind that she'd also get those 6 hits in D&D in about a third of the number of attacks that she'd need to get those 3 hits in GURPS (About 11 turns versus 33 turns).

This isn't even counting some of her recent acquisitions, like the breastplate and full helm. She now has DR 15 on the front of the chest and DR 16 on the head. That might break the conversion even worse, depending on how those factor in.

And all of that ignores that these games have vastly different assumptions underpinning their combat. GURPS expects most of your durability to come from the fact that few attacks will land, while HP loss represents the raw physical damage they take. D&D expects hits to be relatively common, with most of your durability coming from your HP, while HP loss represents not just physical injury, but luck, reflexes, and grit. Much of what GURPS puts into the defense roll, and a fair bit of the rest of combat, are part of HP in D&D. They're completely different schemas, and D&D assumes that highly skilled characters will simply fail more often than GURPS ones will, while moderate-skilled D&D characters will succeed at very hard tasks more frequently than GURPS characters would. Trying to match them up simply by chance of success without accounting for these differences makes for really weird results.

You want a conversion to give a similar feel in a different mechanical environment, not trying to replicate the results of one mechanical environment in a different one that makes very different assumptions.

[2097]

Thank you for all your help so far!

One issue is that in GURPS, the difference between a easy task, an average task and a hard task (page B345) is that much greater than it is in D&D.

To try to explain my goal here a bit. Not to defend my formula as if it were a perfect thing, but to lay out a starting point for what I want it to be able to do once we're done:

1. I want to be able to run stuff from GURPS books without having to convert the entire game over to GURPS.
2. I do not want to eyeball things during play. No "Hmm, I feel like the sheriff in this town would probably be a 5 HD guy…"
3. I don't want to have to convert every character or monster ahead of time. I'll have the option to do bespoke reimaginings of some of them where I expect they'll have an unusual impact, and they'll be better, but it's great to have a formula as a "default" for them for when I hadn't had the chance to convert them more carefully before they became part of the game.

The more parameters that have to match between the two games, the harder this is going to be. So here are the parameters I care about:

1. Skill level—if they hire, let's say, an accountant from a GURPS book, I want her to have approximately the same chances of succeeding or failing with the bookkeeping as she would have in GURPS, except capped at -8 or +12.
2. Fighting. A good calibrator for the formula is if the following two numbers map reasonably well. How many attacks on the GURPS expy does it take for them to be defeated (not necessarily dead, but unable to fight on), and how many attacks from them does it take for their enemies to be defeated.

The parameters I deliberately don't care about are:

• Mapping character points
• Experience level
• What part of the character's die bonus is ability modifier and what part is proficiency bonus
• Extrapolating other numbers from the converted character statistics
• Even working similarly to other D&D creatures

The numbers you need know to fight someone is AC, HP, their to-hit bonus, and their damage expression, and their number of attacks if there is more than one. Maybe damage types and specific vulnerabilities.

If ends up being true that she is around CR6 both offensively and defensively, that'd be great that there's not too much of a discrepancy between her offense and her defense.

Now, creatures in D&D are more fun to fight if there is a good balance between AC and HP, and between to-hit and damage. Let's call that parameter "3m" as in it might be a good thing if that happened but not necessary.

Originally Posted by Phoenix_Dragon

D&D is mechanically built to assume a skilled character will fail more often than GURPS does.

But that's exactly why you would hire a GURPS accountant and not some rando from the monster manual.

Because D&D characters are using special abilities such as Reliable Talent or spells like Knock or Spider Climb whereas the GURPS accountant can just sit down and math it out♥

Combat Reflexes is kind of an important one. It's a big chunk of points and quite valuable, especially to any fighter types.

The amount of points isn't that interesting; NPCs and monsters in GURPS can have any amount of points spent. It's what the ability actually does that matters. (I'm not saying we shouldn't take the most important abilities into account.)

Sw+4. She's using a dueling halberd. Against armor she'd probably use the back-spike (sw+3 imp) to avoid the edge-protection rules, but D&D doesn't even allow piercing damage from a halberd, much less anything like the edge-protection rules.

Oh, damage types is something that is supported, but in a simpler way. Like, skeletons take double damage from bludgeoning for example.

It's a large shield, so DB+3. Plus Combat Reflexes. Her block is 16. Her parry is 15 (16 if she's in defensive grip).

She blocks 98% of attacks!?

So we're looking at somewhere around 60 attacks if they're just whacking away at each other like a D&D fight. Around 30 attacks to get the clone below 0 HP.

But see, this is why I come here to ask♥
Whenever I tried any mock fights in GURPS the fights were just never ending and required sometimes like 300 attacks and sometimes thousands. So clearly just whacking away at each other doesn't work. So how do they fight? That could help us come up with better math for our conversion formulas!

But if we're looking at clone fights, let's look at what she'd do in D&D with your conversion. +12 to-hit vs AC22 means a 55% hit rate. It would take 6 hits to bring her down, so around 11 attacks.

As I noted♥

Except GURPS combats don't work that straight-forward. People love to do flat-empty-plane simulations like this, but I can tell you from experience in my campaign, it never goes that smoothly. You've got feints and beats and tricks. You've got multiple attacks. You've got one person baiting out the good defense so another can slip a hit in. You've got terrain that makes some tactics better or worse. Shields can get beaten up and destroyed. You've got attacks to other locations. You've got chinks in armor.

This is one of the reason I never got very far with GURPS; my li'l mock fights (to learn) were never-ending. Either there would be endless whacking or endless "kiting".

You might want to update your formulas, then, because that's not what it says. It says they're calculating [...]

Yes, I will edit that to make that much clearer. Thank you.

For instance, some stealth-oriented characters in GURPS might be DX 12 with 20 in stealth, or DX 16 with 16 in stealth; your conversion gives the first, master-level sneak only +4 for stealth

Both of those would cap out at +12 stealth. They would not roll DX, they would roll stealth, is the intent. I understand now that this was very unclear in my original writeup.

Her chances of landing an attack in GURPS, against a combatant of high skill (Say, 16, but no shield), is about 25% (And she has many ways of boosting this much higher!). Against a combatant in D&D, of any skill, your formula gives her odds ranging from 75% (Against plate, no shield) to 95% (Against anything AC14 or less.

Aha! In that case, I definitely underestimated the levels of active defense that is typical in GURPS. That's where that error came from. I thought people had like +8, +9 in active defense, something like that.

Thank you so much for all the careful attention you've given this project so far.