Question: Using D20 Stats with GURPS Character Creation

[Jürgen Hubert]

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).

That's how I do it for my conversions (in addition to the GURPS Repository someone linked earlier, I am also running a GURPS campaign set in a Pathfinder world), except that I leave Strength as it is. And I usually pare high Constitution modifiers down to HT 12 or 23 or so - at some point, I want the fight to stop with all but the toughest enemies, and extremely high HT causes fights to drag on and on...

[RyanW]

Originally Posted by Jürgen Hubert

That's how I do it for my conversions (in addition to the GURPS Repository someone linked earlier, I am also running a GURPS campaign set in a Pathfinder world), except that I leave Strength as it is. And I usually pare high Constitution modifiers down to HT 12 or 23 or so - at some point, I want the fight to stop with all but the toughest enemies, and extremely high HT causes fights to drag on and on...

One thing I have thought about doing was that each +/-1 to a D&D stat was (approximately) equivalent to 10 points of GURPS traits. So a high Con might simply be high HT, or some combination of HT, Fit, Hard to Kill, Resistant to Disease, etc. The problem with any direct, deterministic conversion is that the mechanics don't translate on a one-to-one basis, so any conversion needs a thought process to guide it, not just a list of steps.

In other words, translating between game systems is the same as translating between languages, and merely knowing what the words mean isn't the end. You have to understand how the words are put together. Otherwise all your base are belong to us.

[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.

[cmdicely]

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.

That's probably the easiest thing to do, it is very easy to use variant magic systems with GURPS (and, in fact, GURPS has many variant magic systems already written up if you don't like the one -- or two, depending on how you count them -- in the Basic Set; there's a bunch -- many of which leverage the bones of the Basic Set system[s] -- in Thaumatology, one in Powers: Divine Favor, and another in Ritual Path Magic, just to start.)

This is a much more viable idea than trying to merge GURPS chargen with basically D&D gameplay (with some elements of gameplay from other systems.)

My recommendation is you might want to start a new thread asking for tips on how to get the magic system effects you want in GURPS; it'll probably be more productive than this thread.

[Elliander]

Originally Posted by Fred Brackin

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.

On the contrary, I had very specific questions and through all of these comments very little was said that comes close to answering them. I have no interest in spending my days listening to people lecture me when I only had some very VERY specific mechanics related questions.

For example, so far, NO ONE has provided me information on how to convert monsters on the fly. Multiple people suggested I do that, and one link was shown where people have done it, but when I asked for specifics I just get a cop out so OF COURSE I'm going to pay less attention to people who give half suggestions with little or no relevant details.

Originally Posted by zorg

If the magic system is made from scratch, Magery will not do what it says it does.

As I explained, it would be treated as if Magery doesn't exist. In other words, no players would be allowed to select anything Magic related from the GURPS text. That's no different than running a character in a no magic campaign. If the setting has no magic, then there is no magic and you choose something else.

Originally Posted by zorg

I think people feel that the answer to your questions is "Can't really be done, why not try another approach?" :)

I have tweaked other systems in the past. It's nothing new to me. You guys are all trying to over complicate things way too much.

Honestly, I never should have given any details at all about what I plan to do and kept it to mechanic specifics.

[Elliander]

Originally Posted by cmdicely

it is very easy to use variant magic systems with GURPS (and, in fact, GURPS has many variant magic systems already written up if you don't like the one)

Finally, SOMEONE understands what I mean! It is not that difficult to modify a system, I just needed information about it so I can proceed. Even just understanding how the stats in GURPS specifically compare to D20 stats along with key important differences.

.......

Anyway, from what I gathered from the useful information here along with what I have been reading through over the past few days I have the game mechanics mostly figured out.

1.) I'm going to be using GURPS stats. I will just use the IQ as a catch all for any stat that a given spell would look at (usually INT or WIS) .
2.) I'm going to divide character development points into 3 categories. Personality, Combat, and Stats. That way I can be sure that the party has a relative balance of combat ability. It will also ensure that there is a relative stat balance between characters, and will keep a character from stacking stats. I know the game doesn't distinguish them like that, but I know that I can.
3.) I will use FP as an equivalent for spell points, but keep any and all FP mechanics existing in the game.
4.) I am going to change the hit points mechanic. Using 50 combat development points as a base line for a single level, each time the player invests 50 points in combat they will get a hit die. The number of hit die will give me an idea at a glance about the relative combat ability of the player. The player will get the HT value as the starting hit points. I still need to decide if I will have HT affect just base hit points, or if I will have it act as part of a formula adding to the dice roll at each level.
5.) To simulate ability gain in D20 systems, every 50 combat points spent will give the player a set of 10 stat points to spend or save. (so, in effect, every two "levels" they could increase their IQ or they could Strength every level.)
6.) I will likely have to build the Magic system from the ground up after all, but I can play it partially by ear in the first campaign by setting up bench marks. If the player wants a spell from a given book that I haven't bench marked yet, I will work it out in roll play that the "mako stone" needs to be processed into Materia and that the player will need to pick it up later since it is a "custom order" whereas common spells will be easy to come by.
7.) I am going to convert all character movement to feet, and won't be bothering with movement points at campaign start. If a situation calls for it, I will be able to easily convert between the systems of movement while taking into consideration any movement related advantages.
8.) Any Advantage or Disadvantage specifically dealing with Magic, Mana , etc. is off limits to the campaign. For the purposes of character creation it is assumed that humans lack the ability to use magic directly which is why Materia is in use.
9.) We won't need to rely on any Shadowrun machinery from what I read, since it looks like there are enough mechanics to cover that within GURPS itself.

If I work it out like this, I should be able to get all the mechanics to work together the way I want. The only problem that still remains is, of course, the monsters. By giving players hit points in a way that they would get in D20 games I naturally couldn't use a normal GURPS monster, and the GURPS stats are not compatible with D20 games. I need to make a few NPC's anyway for the campaign, so I will make them using these rules and pit them against a few D20 monsters to get a good base line of how to interpret the stat differences and to see if the hit die levels of the characters correspond with levels appropriately or if I will need to adjust it before the campaign starts.

[Dragondog]

Originally Posted by Elliander

For example, so far, NO ONE has provided me information on how to convert monsters on the fly. Multiple people suggested I do that, and one link was shown where people have done it, but when I asked for specifics I just get a cop out so OF COURSE I'm going to pay less attention to people who give half suggestions with little or no relevant details.

For conversion d20 -> GURPS, Ejidoth posted some suggestions for the main stats, though it would have made things clearer if he had chosen not to include the WoD stuff as that didn't pertain to your question. So with some editing of his post, here goes.

Whatever is left of the arrow (->) is the d20 value of the stat and whatever is to the right of the arrow is the comparative GURPS value of the stat. Some of them are ranges, because the stats aren't perfectly comparable.

Originally Posted by Ejidoth

DESCRIPTIVE SCALING

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

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

With skill values, I'd go with something like (if we go by the probability to succeed at a dc 10 task).

d20 -> GURPS
1-2 -> 11
3-4 -> 12
5-6 -> 13
7 -> 14
8 -> 15
9 -> 16
10 -> 17

Higher skills would be correspondingly higher. I wouldn't translate the skills themselves to GURPS skills at all, just leave them as is and let them cover what they cover and any other GURPS skill that seems applicable.

For other abilities, I wouldn't change what they cover, but you might have to change the values in ways that make them work with GURPS, e.g. damage compared to HP.

Of course, if you give monsters and PCs alike d20 like HP, that one thing wouldn't be an issue. But you'd have to figure out how to do that as there are no levels and classes in GURPS.