Question: Using D20 Stats with GURPS Character Creation

[Ejidoth]

Originally Posted by pfharlock

I think that's true for all stats with the exception of st (realizing the debatibility of any statement like this.)

I agree though, more important to preserve the role bonus, so dx and iq for sure should be treated this way.

Way way back, when teaching some of my group GURPS, I worked out some level conversions between GURPS, d20, and World of Darkness stuff. These were the main ones:

DESCRIPTIVE SCALING
This method keeps characters descriptively the same.
Someone at peak human potential in one system is at peak human potential in another.

White Wolf -> GURPS
(this is a pretty good conversion for human characters)

*.... -> 7
**... -> 10
***.. -> 12
****. -> 14
***** -> 16

d20 -> GURPS
(this is a decent conversion in general)

    1 -> 1-2
    2 -> 3-5
 3- 4 -> 6
 5- 6 -> 7
    8 -> 8
    9 -> 9
10-11 -> 10
12-13 -> 11
   14 -> 12
   15 -> 13
   16 -> 14
   17 -> 15
   18 -> 16

WEIGHT SCALING
Use this method if you want to keep the character's lifting strength the same.
Non-Strength stats probably shouldn't use this method.

White Wolf STR -> GURPS ST
(for mundane humans, you should use the descriptive scaling instead)

*.... .....  6 ST
**... ..... 10 ST
***.. ..... 16 ST
****. ..... 20 ST
***** ..... 25 ST
***** *.... 28 ST
***** **... 30 ST
***** ***.. 32 ST
***** ****. 35 ST
***** ***** 39 ST

d20 STR -> GURPS ST
(should be very accurate for the most part)
 
    1 STR -> 5 ST
 2- 4 STR -> 6 ST
 5- 6 STR -> 7 ST
    7 STR -> 8 ST
 8- 9 STR -> 9 ST
   10 STR -> 10 ST
11-12 STR -> 11 ST
   13 STR -> 12 ST
   14 STR -> 13 ST
   15 STR -> 14 ST
   16 STR -> 15 ST
   17 STR -> 16 ST
   18 STR -> 17 ST
   19 STR -> 19 ST
   20 STR -> 20 ST
  +10 STR -> x2 ST

[Elliander]

Originally Posted by Anders

One rule-of-thumb I've seen floating around is that to convert a stat from GURPS to D&D the D&D stat is equal to a GURPS stat of 10 + D&D stat bonus. So D&D Str 18 (+4) is equal to GURPS ST 14 (10+4).

So in essence, when converting from Gurps to D&D, for every 1 point over 10 in Gurps the character gets 2 points in D&D?

Originally Posted by Ejidoth

Way way back, when teaching some of my group GURPS, I worked out some level conversions between GURPS, d20, and World of Darkness stuff.

I'm a bit confused by the ranges. They look good for converting an existing character, but what about a character that doesn't exist yet? A range of values wouldn't really be helpful in that scenario.

[Fred Brackin]

Originally Posted by Elliander

So in essence, when converting from Gurps to D&D, for every 1 point over 10 in Gurps the character gets 2 points in D&D?

.

As an experienced Gurps and Pathfinder player I would say that this would match the usual frequency with which such relative Attribute levels are seen. That is a Gurps 14 will probably ben about as common in Gurps as a D20 18 was in D20.

ST is a small exception in fantasy games sometimes going up to 17 or more but that's a minor issue.

HP really are a problem. They simply don't increase in Gurps the way they do in D20 games so spell damage that does increase will be a problem, Converting monster hit dice to Gurps can also be a large problem with very limited success for any simple mathematical formula.

As to your specific questions while I've been with Gurps and Pathfinder from the beginning of each game I don't really understand what you're trying to do. I also suspect that you're trying to do things the hard way. I wouldn't try and mix game systems the way you seem to want to. Game rules aren't really modular.

[Elliander]

Originally Posted by Fred Brackin

HP really are a problem. They simply don't increase in Gurps the way they do in D20 games so spell damage that does increase will be a problem, Converting monster hit dice to Gurps can also be a large problem with very limited success for any simple mathematical formula.

See, knowing that makes me less willing to use GURPS stats. If I kept the Gurps stats as they are and use a D20 Magic system, the Magic would over power everything.

Originally Posted by Fred Brackin

As to your specific questions while I've been with Gurps and Pathfinder from the beginning of each game I don't really understand what you're trying to do. I also suspect that you're trying to do things the hard way. I wouldn't try and mix game systems the way you seem to want to. Game rules aren't really modular.

I said exactly what I am trying to do on every page of this thread so far.

*ahem*

I chose to use GURPS because it lacks a class system and has versatility in creating multiple types of characters. I want to strip out the magic system, and use a new magic system that I am creating based on a D20 system. Instead of rewriting all of the spells, and rewriting all of the monsters, I wanted to simply switch out the magic and use D20 stats. That's it.

Think of the items as being like characters in and of themselves, an object that contains the spells. The only interaction between the characters and the spell casting is the spell points and caster level - along with of course the effect it has on targets. The item will also have it's own experience system, and will gain experience as it is used in combat separately from character development points. To access a higher level spell, you both need to have unlocked a higher level spell, and have the appropriate caster level. Just think of the magic as being compartmentalized in this campaign. Little more than a weapon, if thinking about it that way helps. I know people run no-magic campaigns, so think of this as a no-magic campaign where an object has a magic like effect if that makes it easier to grasp.

[Jürgen Hubert]

Originally Posted by Elliander

I chose to use GURPS because it lacks a class system and has versatility in creating multiple types of characters. I want to strip out the magic system, and use a new magic system that I am creating based on a D20 system. Instead of rewriting all of the spells, and rewriting all of the monsters, I wanted to simply switch out the magic and use D20 stats. That's it.

Think of the items as being like characters in and of themselves, an object that contains the spells. The only interaction between the characters and the spell casting is the spell points and caster level - along with of course the effect it has on targets. The item will also have it's own experience system, and will gain experience as it is used in combat separately from character development points. To access a higher level spell, you both need to have unlocked a higher level spell, and have the appropriate caster level. Just think of the magic as being compartmentalized in this campaign. Little more than a weapon, if thinking about it that way helps. I know people run no-magic campaigns, so think of this as a no-magic campaign where an object has a magic like effect if that makes it easier to grasp.

Okay, let's go with that.

The big question is how compartmentalized you want your hybrid setting to get. d20 compartmentalizes the following:

- Attributes
- Hit Points / Hit Dice
- Skills
- Feats
- Saving Throws
- Class Abilites (including spells)

There is an overlap between these (for example, feats can modify some of the others), but ultimately each progresses separately.

GURPS doesn't compartmentalize any of these (or rather, their equivalent). Each can be raised separately, which leaves less points for the other. Want someone with a zillion hit points, but no useful combat skills? It's doable, though not necessarily recommended.

But frankly, coming up with a hybrid system between those two is rather difficult, since you'd have to figure out what each d20 element should be priced in GURPS, or how each GURPS element translates into the d20 rules. Given the complexity of both systems, that's a huge amount of work.

I have a recommendation which may fit your needs better: Don't start with GURPS, but with Mutants & Masterminds (particularly the 2nd edition, since the 3rd edition has evolved away from its d20 base). This is a "generic system" with a point-buy base, similar to GURPS. There are some notable differences - for example, damage and injuries work with a saving throw system rather than hit points - but since it is based on d20, it will be much easier to come up with a conversion or hybrid system than it will be with GURPS. It doesn't have quite the flexibility of GURPS, but it should be close enough - and if there are any bits of GURPS you like, you can still attempt to convert them. That will be much easier than converting the whole thing.

[Kuroshima]

We're trying to tell you that you're going to do a lot of work on something that at best will only somewhat work. That's the usual nature of mechanical conversions (same as mechanical translations, try giving Google Translate a text in a foreign language, let's say, a fragment of the original Romance of the Three Kingdoms in it's original Chinese and see if what you get could be sold as a paperback novel. The answer is no, and most people doing translation will tell you that trying to fix it is worse than simply going back to the source material).

The base assumptions (axioms) of each system are too different for a mechanical conversion. One is abstract and very "gamist" in that there are a lot of things that are there to make it a better game, and common sense/realism/etc be damned. The other is very detailed and "simulationist" in that some things that look cool do not work well because they are stunts that people do that are showy but ineffective. We could argue on the merits of each system until we all turn blue.

Now there's a couple added issues: First, most people here like and play Gurps, and for them conversions TO GURPS are something they've already done in the past. Conversions FROM GURPS are another matter altogether. Second, GURPS is designed to make importing concepts from other games relatively straightforward, by making most (not all, but most) of the base assumptions visible, while D20 hides most of it's inner workings in neat black boxes that are often the same price (feats, skills, spells, levels,...) but with widely varying value. Being able to tweak GURPS is an advertised feature, and often you'll find multiple ways to handle the same thing, with different feelings, levels of resolution, etc. Trying to tweak D20 can result in the whole thing crashing down with no warning, as there are non-obvious interconnections between subsystems.

Converting TO GURPS is often a matter of finding the GURPS rules that are closest to what result you want, and maybe tweaking them a bit (often using the provided variations). Converting to D&D often requires you making stuff up and trying to end up within an order of magnitude of existing material (What's the Int or Wis or Cha of this monster? It must be sky high because it has to be a challenge to high level adventurers and it uses it for calculating the save DC of it's abilities. Serously, many undead have sky high Cha because they use it for their abilities! and yet they are certainly not charismatic in the usual sense of the term). Same with things like hit dice, attack bonus, abilities, etc.

[Dalillama]

Originally Posted by Elliander

Well, the only major mechanics I was looking at were the Movement Point system (so I would measure everything in feet unless in an Urban situation and then on the fly convert to movement points), and Cybernetics rules such as "Essence" where magical ability takes a hit by having implants since there is less life energy. For spells I was just going to bench mark what the players want and write something up that is comparable.

You're probably best off defining Essence as an ER, possibly based on fatigue initially, and set limits to how much someone can buy of it based on how many points of cyberware they've got. Alternately, if you want to keep using FP as the equivalent of Magic Points, you could rule that, say, each 5 points worth of cyber advantages reduces the amount of fatigue you can spend by one.

Thanks, but again I am quite a bit more familiar with combat mechanics of D20 systems and have quite a bit more to work with there.

I don't see any way that GURPS characters can be built to meaningfully function in the D20 combat system. Hit points, armor, weapon skills, defences and hit probability mean completely different things and are based on completely different principles.
In D20, hit probability is determined principally by class and level, with bonuses from high strength and penalties from lack of proficiency.
In GURPS, hit probability is determined principally by DX and weapon skill level.
In D20, Hit points are a summary of all your defences except armor, which affects the opponent's hit probability
In GURPS, Hit points are only the ability to sustain damage, and tend to stay fairly static over a character's career, while most defence is based on rolls against Parry, Dodge, and Block, which are skill and attribute based. Armor reduces damage.
The differences go on, and I don't think there is a way to meaningfully translate GURPS combat stats into something that will work in D20

I'm a bit confused by the ranges. They look good for converting an existing character, but what about a character that doesn't exist yet? A range of values wouldn't really be helpful in that scenario.

I can't see any way to do that; the only way I can see to do it is to build a character and then try to convert, but even that seems difficult and unwieldy to the point of pointlessness.

That makes absolutely no sense whatsoever, and it's not like anyone has pointed out what a full conversion even means since those strengths and weaknesses don't exist in other systems at all.

That's exactly the problem; no one is sure what a full conversion means, because no one fully understands what you are and aren't trying to convert, and to what. To a large extent, though, a 'full conversion' isn't really possible; the fundamental assumptions of the two systems are too different.

As I explained, this is not as simple as saying "High Technology" because I am combining multiple environments. As I said, this will be both Tech Level 10 and Tech Level 4 areas. Magic will be based on items, and players will be able to swap them out like any other piece of equipment.

So you are using the GURPS TL system, then? That was what was being clarified. Some areas will be at one TL and others at another, but you're designating the tech levels using GURPS terminology, and will persist in this during play?

Originally Posted by Elliander

Look, I appreciate the suggestions, but this is really getting frustrating. I asked a few very simple questions, and EVERYONE is getting off on these tangents about what they think I should do without actually ANSWERING. And the most frustrating part is that these extra suggestions don't even have any real answers to them.

A lot of the tangents are for the purpose of clarification, because your initial questions are not as simple as you are assuming. Trying to combine the systems like this is a very complex thing, and in order to assist, people need to know exactly what parts you're using from where.

For example, one suggestion said I should convert the characters that aren't even created yet from Gurps, but say how that would even work.

I believe that suggestion was to create the characters in GURPS, and then convert them.

Other suggestions said I should convert all the monsters, but again, didn't say how that would work either.

Pfharlock gave a brief synopsis in post 18, and there are many threads with more detailed recommendations that can be found using the Search This Forum option

Everyone has an idea about what they think I should be doing, but how about just giving me the tools I need to make that decision on my own?

We're trying to figure out what tools those are, and many of them simply don't exist.

I JUST want to use GURPS as a Character base, strip out the Magic system, use an alternate system. That's it.

But you can't do that; the GURPS character generation system doesn't exist in isolation, it creates characters that work within the GURPS rules framework. It's not equipped to create characters that can function in Pathfinder rules.

Originally Posted by Elliander

I would be open to, instead, keeping the stats in the Gurps form and then modifying how the Magic system is used, but I am not going to be using the Gurps Magic system in this campaign.

No one has suggested the standard GURPS magic system. The Path/Book system from Thaumatology would be the easiest to adapt to the Spheres of Power system, but there's no point since you're basing all the magic on materia anyway. Determine what skill you roll against to use the materia and what it does, and there you go, it's equipment.

Originally Posted by Elliander

In this particular case, the rules certainly exist in an "almost" vacuum. On the contrary, I specifically chose Gurps because I fully recognized that for what I wanted to do a D&D base would not have worked out well at all.

That's exactly what people have been telling you; the D&D rules aren't going to do what you want, and it's not clear why you insist on trying to use them.

Also, one of the reasons why I wanted to use a movement point system instead of "feet" or "yards" was that I could add additional costs to types of spells and actions to help with balance.

I'm not sure what you mean by this; you want some spells to reduce your capacity to move during a turn that you cast them? In GURPS, that would be handled by defining various uses of materia as free (can move full move and still do it), standard(can move some, but not full move), full round (can't move), or multiround actions.

As an additional problem, how are the rules for Cybernetics in Gurps as compared to Shadowrun?

Cyberware grants Advantages, which are bought with points; they usually have limitations like Requires Maintenance and Electrical.

[Elliander]

Originally Posted by Dalillama

That's exactly the problem; no one is sure what a full conversion means, because no one fully understands what you are and aren't trying to convert, and to what. To a large extent, though, a 'full conversion' isn't really possible; the fundamental assumptions of the two systems are too different.

I'm sorry, but that's Bull. First of all, the people who are suggesting I convert all of the monsters on the fly know EXACTLY what is being converted in that case. Second of all, I outlined exactly what I am doing and why more times than I care to count. Repeating myself any more is pointless. If you guys didn't read it the first few times you aren't going to read it at all.

Originally Posted by Dalillama

So you are using the GURPS TL system, then? That was what was being clarified. Some areas will be at one TL and others at another, but you're designating the tech levels using GURPS terminology, and will persist in this during play?

*sigh* Again, I spoke about that more than once.

Originally Posted by Dalillama

A lot of the tangents are for the purpose of clarification, because your initial questions are not as simple as you are assuming. Trying to combine the systems like this is a very complex thing, and in order to assist, people need to know exactly what parts you're using from where.

I specified exactly what is being swapped out and why on multiple occasions.

Originally Posted by Dalillama

But you can't do that; the GURPS character generation system doesn't exist in isolation

Refer to my last post.

[Fred Brackin]

Originally Posted by Elliander

If you guys didn't read it the first few times you aren't going to read it at all.
.

I've read it every time you've written it. That doesn't mean it makes sense.

You ask for people who know more about Gurps than you do to help you but you don't seem to want to hear what they say. The answers you appear to want don't exist to my knowledge.

I would probably do what you say you want to do entirely within Gurps. Especially the part about creating a new magic system. Mixing magic and tech and different tech levels is also the sort of thing Gurps does well.

If not I would do it within a hybrid D20 framework borrowing from Mutants and Masterminds or True 20 which use point buy character creation with D20 stats.

I would not try and use bits from both. They have largely irreconcilable basic philosophical assumptions.

[Kallatari]

From what you've said, I'll echo Fred and a few others in saying that I think you'd do better using Mutants and Masterminds 2E (M&M 2E) or True20 (T20).

M&M is practically GURPS d20; it's points based, lets you build what you want limited only by GM whim as to Power Level and campaign setting restrictions. There's a nice variety of skills, which I found were better detailed and elaborated than D&D (not familiar with Pathfinder so can't compare). There's a whole section on equipment vs gadgets, and you can use the gadgets for your magical items, just adding a few tweaks to match what you want.

T20 is sort of a M&M-class-based d20 hybrid. It's d20 boiled down to 3 core classes, which effectively determine which Combat Bonus, skills points, and list of Feats you can choose from each level. Powers (a.k.a., spells and magic) are special feats only available to the Adept class. In T20, magical items effectively grant the wielder feats. So you can have a magical staff/wand/gun/whatever of lightning to let you "cast" lighting. Here, powers - whether from an innate feat or one granted by an item - have a "drain" which limits how often you can use it; you can probably tweak that relatively easily to get "magic points" or whatever measurement you were planning to use.

Now, T20 comes with an appendix on how to convert monsters, spells, weapons, etc., between normal D&D/d20 and T20. It pretty much focuses on how to convert HP to their Toughness Saves and vice versa as almost everything else can be used as is. M&M uses the same Toughness Save concept, so the T20 conversion rules work for M&M (2E) as well. But in a nutshell, other than the HP/Toughness thing, you can pretty much use the monsters/stats/spells/abilities as is between all the systems. Most of your work would be done for you, except for your setting-specific tweaks on your magic system. T20 even has TLs and how to build items for each one.

I'd suggest using both. T20 for the conversion rules, tech items and gadgets, but M&M for the actual character building. The Array from M&M (similar to GURPS Modular Abilities) sounds like it may be useful for your magic system.

Side note, M&M 3E has additional changes compared to 2E/True20. You'd have to do a bit more conversion work from the d20 base, but it's still not so bad.


If you really want to stick with GURPS, well, I'll again echo what others have said in that I'm not sure what exactly you're looking for. I've seen quick notions of what you kinda possibly want but not the specifics or the details. And GURPS is all about details.

But that aside, to answer one of your question: Yes, it will be a lot of work. Conversions of RULES always are (as opposed to getting something similar out of existing rules). GURPS can cover almost any concept internally within its own rules. But it can't be forced other rules from other systems. You'd therefore be rebuilding from scratch in GURPS.

On the positive side, what you want might already be done somewhere. There are d20 to GURPS monster conversion out on the web (a whole wiki of them IIRC). You can probably grab those. There are various character templates bouncing around, so you could check those out. GURPS Dungeon Fantasy pretty much covers the "conversion" of your D&D classes for example, although that would require a purchase.

As to your magic system, there's potentially a lot of work. Realm Magic from GURPS Thaumatology might be close to what you want, but, again, I'm not sure what you want exactly, so can't say for sure. Either way, you'd want GURPS Thaumatology (another purchase), and that's a guide on how to build your own, not a full example, so there's more work there for you.

But even if it is done, you'll find that d20 "game balance" concepts, such as CR, etc., really don't work with GURPS, and therefore even converting is not always a good idea. Converting a D&D Ancient Dragon that's the size of a castle into a realistic GURPS equivalent would pretty much slaughter any party out there. Its HP and DR would be untouchable for any party. You need to do more than convert. You need to modify it to fit within the concepts of the rules (the ancient GURPS dragons are the size of elephants, IIRC, and thus much more manageable for GURPS PC to defeat). And that's where the real work is for any conversion. You can't just say, for example, this AC becomes this DR; you need to draw a line somewhere and see what becomes a party-killing level, and then modify your monsters to not cross that level. It's pretty much the same issue of converting massive-damage spells of ever-increasing HP games into a game where HP are static. High level d20 monsters just aren't designed for the static HP of GURPS. Ditto for magic items, etc. And the problem works both ways; converting from GURPS to d20 just doesn't give you the damage or HP you need to survive at "higher levels."

I hope this was helpful.