Physics, Rules, and World-Building

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Post originally by Bard Bloom at 2002-10-28 09:47:01
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In World Tree (www.world-tree-rpg.com) we took the point of view that the game rules were the best approximation of their form of the game-world's physical reality. Presumably the simple Skill+Attribute+d20 rolls we use are more complicated in World Tree reality, but they *do* have the right kinds of consequences -- technical and social.

For one example, World Tree has pervasive magic: *everyone* can use at least simple spells. Children start learning them at age 3-5. One of the biggest causes of child mortality is miscast spells; the chance of dying from a botched spell in the rules does indeed match the child mortality rate in the anthropological section.

As Schmiedekamp points out, magic does modify craftwork (and most other parts of society). World Tree magic is flexible but limited: a baker doesn't have enough cley (spell points) to do all the baking by magic, but does have enough to repair a dropped wedding cake, or clean up the bakery at the end of the day if she has cley left by then.

We consider World Tree's technology to be magical: they use magic for the same sorts of things we use electricity for, say. The supply of magic is more limited, and highly-skilled mages cannot be mass-produced, so magical technology has quite a different flavor than terrestrial scientific technology. But the analogy is good to remember.

The relationship goes both ways. Mentador magic, mind-magic, is considered quite evil. Everyone has the basic power to use it. Few people do so, even harmless or beneficial uses of it. In play, we have had Fressis send Anoof a telepathic warning about a trap closing on him -- and, afterwards, had Anoof nearly bring legal charges against Fressis for using Mentador on him. There's no physical reason for this hatred of Mentador: certainly it is dangerous if misused, but Pyrador and Corpador (fire and flesh) magic are just as bad. The in-world reasons are purely historical and social. (There are different game-design reasons of course.)

We considered doing World Tree as d20 or GURPS or some other generic system, and, ultimately, couldn't bear to. The culture and the magic system are too intimately tied to be disentangled.

(Not that all games have to be so tightly constructed -- though for a game where the emphasis is on a new and non-terrestrial world, I certainly recommend starting out separating them.)

-- Bard Bloom
www.world-tree-rpg.com

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Post originally by Rakshasa at 2002-10-28 10:58:59
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I first want to say that I don't know your game, and for all I know it may be very good.

I fully agree with the column's hypothesis that rules have a heavy influence on the setting and thus on the mood.

This means that your approach of trying to emulate real-world physics can only make your game look like a physics textbook. Fortunately, while many game designers claim (and think) they are after realism, intuitively they follow verisimilitude : emulating the rules not of the real world but of a particular genre (literary or otherwise).

Of course, while I have a great respect for the third edition of D&D (and regularly play under those rules), I think that the whole D20 trend is utter madness, as a single set of rules can only support a very narrow group of genres (that also applies to so-called generic systems like GURPS or HERO). I may not make many friends saying this, but every interesting setting has a distinctive mood that can only be translated in RPG form by a careful and dedicated design from scratch.

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Post originally by Bard Bloom at 2002-10-28 11:38:52
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Ah, I must have misspoken. We make no attempt to emulate real-world physics. Our world, after all, is a very large tree with no planet to grow on; the sun is a hollow crystal globe that rolls on a track around the sky, and is lit each day; such basic terrestrial laws as universal gravitation and conservation of energy are universally violated.

(And we didn't try to emulate some constructed physics in the rules. We had some simple core rules in mind, and took them seriously -- "On World Tree, hit points make sense (viz., are a good approximation of physical reality). On Earth, they make no sense. World Tree biology can't be very Earthlike, then... what *could* it be?" The rules and the setting grew up together; considerations from each one mattered a lot for the other.

(There's not yet much of a literary tradition of highly civilized, heavily magical multi-species but very nonhuman people living on giant trees, so genre considerations were fairly general at best.)

There's no reason you couldn't do the same exercise with D&D, say. You might learn quite a lot...

-- Bard
www.world-tree-rpg.com

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Post originally by Mendel Schmiedekamp at 2002-10-28 18:52:35
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Which explains why I like your game so much, it just feels consistent.

-Mendel

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Post originally by Bard Bloom at 2002-10-28 19:30:42
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We are honored!

-- Bard Bloom
bard@bestweb.net

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Post originally by Torben Mogensen at 2002-10-29 00:33:15
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Rakshasa wrote:
-------------------------------
Of course, while I have a great respect for the third edition of D&D (and regularly play under those rules), I think that the whole D20 trend is utter madness, as a single set of rules can only support a very narrow group of genres (that also applies to so-called generic systems like GURPS or HERO). I may not make many friends saying this, but every interesting setting has a distinctive mood that can only be translated in RPG form by a careful and dedicated design from scratch.

=================

I hearthily agree, except for the "from scratch" qualification. No game is created in a vacuum - a good game designer will be familiar with dozens of different rule systems and know how successful each is in modeling what it intends to model. He can then take promising mechanical elements from other games and twist them to his purpose as well as invent new mechanical elements when none exist that serve the purpose.

Not only does the accumulated experience of past games designers help the designer to design his game, it also helps players to play it. Players can more easily relate to a rule set that has similarities to something they have played earlier than to something entirely new, and the familiarity with some aspects of the rules will also make them more appreciative of the differences, at least when these improve how well the rules fit the setting or ease the play.

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Post originally by Mendel Schmiedekamp at 2002-10-29 04:23:55
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I don't think from scratch means avoiding mechanics which have been done before. This is rarely practical. Rather it attempts to build in the entire structure of the rules to best fit the setting. What it means is that mechamics are included because they make sense, not simply because they are accesible, even though this could be a design consideration. Every rule she be there for a reason, not just added en masse. This makes the rules and the setting support each other, and means learning one makes the other more accesible.

If this is done correctly the learning these strange mechanics gives double duty, by also making the setting accesible. We often avoid setting learning time as a criteria for accesiblity but it is vitally important, everytime a player is told, "you don't really want to do that." we find a failure in setting comprehension. After all settings are constraints in and of thesmselves. If they mesh with the rules, then you only learn one group of them. But if you insist on modifying an existing set to get close, you end up learning 2 different sets of potentially contradictorary rules. The later is far more wasteful.

-Mendel

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Post originally by No One of Consequence at 2002-10-31 20:05:16
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"For one example, World Tree has pervasive magic: *everyone* can use at least simple spells. Children start learning them at age 3-5. One of the biggest causes of child mortality is miscast spells; the chance of dying from a botched spell in the rules does indeed match the child mortality rate in the anthropological section."

So, everyone botches an average of only *one* spell during childhood (% death from a botch = % child mortality), AND nobody gets any better at surviving spell botches, despite having practiced since early childhood?

It's fine for game purposes, but it doesn't seem quite as consistent as you claim.

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Post originally by Bard Bloom at 2002-11-01 11:16:36
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That is an astounding interpretation of what I said; I'm afraid I barely see how you got it.

*sigh* This is more detail than I wanted to say

Children will botch many many spells; the kind of magic they
start with is fundamentally imprecise. (As they get older,
they will learn more reliable forms, but the more reliable
forms build on the first one.) There is a small chance that
a botch will kill a child. This is not qualitatively
different from, say, human children on playground equipment,
though the numbers are worse.

Crunching through the probability calculations gives a rough
probability that a child having a fatal mishap before they
learn the more precise forms of magic.

(There is also a small chance that a child will kill another
one semi-intentionally -- by magic or whatever -- , which is
a separate calculation that also went into child mortality
rates, as did a few other things. It turned out that the
danger from spell botches was the dominant term though.)

Hope this helps,
Bard