Question: Using D20 Stats with GURPS Character Creation

[johndallman]

Originally Posted by Elliander

Exact conversions are not as important as game balance. It's OK if a stat conversion isn't perfect as long as the game balances out.

Unfortunately, game balance as reflected in combat challenges is the thing least likely to survive any kind of conversion. In D&D family systems, the primary measure of characters is combat power. That simply isn't true for GURPS, which had quite different objectives in its design and has had quite different pressures in its evolution.

... if I went further I would lose what I hope to gain by adapting GURPS mechanics.

What are you actually hoping to gain? That hasn't been clear so far, and if we understand that, we may be able to suggest a practical way of accomplishing it.

[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).

[Elliander]

Originally Posted by johndallman

What are you actually hoping to gain? That hasn't been clear so far, and if we understand that, we may be able to suggest a practical way of accomplishing it.

I explained that in a previous comment. If you need a full campaign scenario synopsis I can provide it though. Suffice to say, it just seems like it would be easier to adjust character creation to suit D20 adversaries than to modify every single monster I would send against the players.

[zorg]

Originally Posted by Elliander

I explained that in a previous comment. If you need a full campaign scenario synopsis I can provide it though. Suffice to say, it just seems like it would be easier to adjust character creation to suit D20 adversaries than to modify every single monster I would send against the players.

It's relatively simple to whip up monster stats, and there's a bunch in various supplements, and on this forum. In my opinion, working up monster stats would be much easier than an attempt to map various stats over different systems... but it's your call, of course.

[Dalillama]

Originally Posted by Elliander

OK, well here's the basic scenario I came up with. An alien city modeled after Midgar in FF7 lands on an island in the "Pirates & Dragons" world. They are Tech Level 10, while the surrounding world is Tech Level 4. The players begin as part of this city as the alien invaders, but there are internal social conflicts as well resulting in a campaign that has Urban Warefare, Ship/Airship Battles, Tank Battles, Conquests, Dungeon Crawls, and Battles with Monsters. Because it's modeled after a FF7 city we decided it would be interesting to use a system modeled after "Materia" and we decided to model it after a combination of spells from "Spheres of Power" and "Shadowrun 3e". Each Materia has it's own experience that unlocks higher levels of the spells, weapons are modified to have Materia slots, etc. Because Magic will essentially be something embedded into weapons there is very little reason for anyone to specialize in a spell caster, and given the varied backgrounds the players wanted to use I felt that a system of Advantages/Disadvantages would suit it well.

Looking at the "Spheres of Power" kickstarter, I don't see how you're going to combine that with any edition of Shadowrun. Since the materia are going to be the source of the magic (as I understand you), and are basically pieces of equipment it sounds like you might want to introduce a set of M/H skills called e.g. "Alteration Materia", "Mind Materia" etc, and require a leveled advantage like magery to unlock more advanced uses of the materia in question. The easiest way to put Spell Points into GURPS would be to either have the devices require FP to use or allow people to buy an Energy Reserve that the materia will draw on.

I will be creating the vast majority of NPC's myself for use within the city, but the surrounding world is populated by a variety of characters that will only have stats for D100 and D20 rules listed.

There's a huge load of D20 monsters here.

It really isn't a problem if I combine WIS/INT into IQ for the purposes of casting spells, but I wanted to make sure that whatever happens the game has balance.

In GURPS, spellcasting is usually based on IQ, yes.

Ya, I'm starting to see that. I suppose I could only look at just the party's combined combat points to determine the party's collective combat rating, but it's still going to be an issue of figuring out that base line.

You'll get a better approximation by comparing enemy damage and chance to hit against PC DR and defenses and vice versa. There's a number of threads where people have tried to work out formulae.

Well, I am referring to any Advantage or Disadvantage that specifically mentions and/or targets a stat in any meaningful way. That includes being affected by stats.

Generally speaking, GURPS advantages aren't modified by stats, nor do they modify them; Pathfinder hasn't got anything called Advantages AFAICT, and I'm not really familiar with the d100 system, but since you're not using that for chargen I'm not seeing where it's relevant.

Originally Posted by Elliander

I explained that in a previous comment. If you need a full campaign scenario synopsis I can provide it though. Suffice to say, it just seems like it would be easier to adjust character creation to suit D20 adversaries than to modify every single monster I would send against the players.

I strongly suspect you're wrong.

[johndallman]

Originally Posted by Elliander

I explained that in a previous comment. If you need a full campaign scenario synopsis I can provide it though.

Your postings don't describe specific GURPS mechanics that you want to use. You might, for example, be wanting to use the Technology Level system, but you haven't said so.

I think you're going to find your life much easier if you identify the GURPS mechanics that you want and create ways of representing them in the game system you're going to use for play.

I can point you to a high technology system for D&D that you might find useful; it isn't widely used but it is good fun.

[pfharlock]

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).

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.

[pfharlock]

Originally Posted by zorg

It's relatively simple to whip up monster stats, and there's a bunch in various supplements, and on this forum. In my opinion, working up monster stats would be much easier than an attempt to map various stats over different systems... but it's your call, of course.

I'll second this sentiment. Instead of pulling from like 5 systems trying to make a cohesive whole, I would pick one and use it to model the setting you are trying to achieve.

Assuming that system is still gurps...

For monsters I would either do a rough conversion on the fly of their capabilities or use the resources others have mentioned where people have already converted d and d monsters to gurps.

If converting on the fly think of things like how much damage does this thing do, how well does it defend, how likely is he to land a hit and lastly what "special" abilities does he have? If you get really good with gurps rules you can do this in your head, I wouldn't worry about tallying the points, just worry about porting the effects faithfully.

The materia concept you mentioned could be modeled in a variety of ways in gurps. If it were me, I would consider using gurps magic mechanics, make each different type of materia it's own college, and then enforce the optional rule that you have to take magery seperatley for each college. Not sure if I would use the spell lists or not. It would be easier to use them, but they may not map well in which case you'd have to come up with new ones.

This way of doing it (using gurps magic) has its difficulties and you would have to improvise allot, but also some advantages.

Edit: the magic mechanics are presented in the basic set, so that might be all you need, but they are greatly expanded with full spell lists in the dedicated magic book. If you decide not to use the spell lists then that book becomes less compelling. The part I would think would map well is the idea that spells are powered by energy. The default assumption in the default magic system is that this energy is supplied by the mage. With materia you could pull it directly from the environment leading to ridiculous power levels, or you could set individual mana levels in a given area one for each materia type. There's allot of weird stuff you could do.

Just crazy thoughts, take with a grain of salt

[DangerousThing]

I'm assuming that you are using a predefined setting that you've bought or that you are using a setting built from various pieces.

I've found it much easier, in my experience, to translate monsters and simple NPCS to GURPS than the other way around. Most of the time I do it on the fly. However, before the game begins, or at least before the characters meet them, you should really think of the high mucky mucks in your setting. I have found in my games is that it's too easy to make them too powerful. High social standing doesn't usually mean high combat or magical abilities. On the other hand, hight social standing usually means they have followers who can be ordered to do things to the people who annoy them.

My strong recommendation: use a single rules system.

If necessary, use GURPS and work out complete character descriptions with the players than create the characters yourself. For this, I'd recommend the program GURPS Character Assistant, available at e23.sjgames.com. For $15 it's a bargain, if only because you don't have to do the math for all the interactions. Then don't show the players their character sheets, or just give them a minimal sheet with words rather than numbers. If you do that, then make sure that the character matches the description.

I've done this with several games, and it seems to work out.

[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