[MUD-Dev] Respecting NPCs

J C Lawrence claw at 2wire.com
Thu Oct 25 14:34:40 New Zealand Daylight Time 2001

On Thu, 25 Oct 2001 10:55:47 -0700 (PDT) 
gamaiun  <gamaiun at yahoo.com> wrote:

>> How about inscrutable not-quite-deterministic NPCs?

> I think I see what you're getting at by describing this _other_
> kind of NPC - compelling, mysterious... living.

Actually, no.  Compelling NPCs are interesting to be sure, but
there's little reason for them to be either common or even

  In a world of independent prickly stick-up-for-themselves
  characters, the sheep is very visible.

Defining mystery is not easy.  I'm looking for NPCs which are not
necessarily mysterious in the sense of having obvious secrets or
hidden purposes/actions, but rather mysterious in the manner of
simply not revealed but visibly present.

  Your workmate is a quiet type.  You not he has a wedding ring,
  that he brings in lunch in paper bags which often have crayon
  scribbles, and that there's a child's car seat in his car.  From
  this you determine that he's married and has at least one kid who
  is under 4 years old.  

  Yet you never see the kid, the kid is never mentioned, you don't
  know the kid is even his (versus a relative/neighbor's), you know
  nothing about his wife or even if she exists or is alive, etc.

  You note that he collects empty plastic bottles at work from the
  cans of licorice and pretzels and that he takes them away when he
  has a dozen or more.  Its an obviously purposed activity, but one
  whose purpose is neither revealed or necessarily subject to
  exposure thru analysis or observation.

It is mysterious in the sense that there is a mystery and it is not
answered.  It is not mysterious in that there is no light cast on
the mystery, no reason for attention on it, and no vaunted secrecy
surrounding it.  This of course doesn't mean that the murkier sorts
of mystery can't be there, just that they are not required.

Living?  Hard to define that one.  In the sense of "credible" (the
term I used), yes.

> What shall we call this kind of NPCs? I mean we need some kind of
> terminology for this discussion. Compelling? Literary-quality? 
> Alive?

"Incidental outgrowth"?

> On the same note, what are the qualities of such NPCs, that make
> them stand out from the mechanical rest?

They are visibly purposed, their activities are credible, and they
reward (if not necessarily profit) examination and analysis.

> Here's a brainstorm of qualities, to start with.

>   - Interaction? These NPCs need to be able to interact, both with
>   the game world, and with players. If they merely interact with
>   the game world, but never with players (such as Father William,
>   who was only mentioned in a story, but never, AFAIK, interacted
>   with Alice), then they're nothing more than well-crafted pieces
>   of literature.

I don't see this as a useful distinction.  Its critical in that it
limits player interaction requirements from an implementation
viewpoint, but has little effect on perceived story, or use by a
player in their own stories.

>   What makes compelling _literary_ characters is another matter
>   entirely, I think, and I'm sure volumes have been written on the
>   subject.  

The criteria of what makes and defines human interest, or
specifically, what identifiable qualities will necessarily invoke
that sort of interest and quality reaction is still a very murky

>   What makes _NPCs_ unique is that players can interact with them,
>   adding another dimension.

What if players were unable to directly interact with them (eg no
speech, and no direct effects) other than by manipulating the world
around the NPC and then seeing what the NPC did as a result?

>   If they only interact with players, but not with the game world,
>   then they come across as 'mechanical', as simply props for the
>   players' benefit.


>   - Purpose/Motivation?  Purpose is a dangerous word, actually. It
>   implies that the NPCs were put there _on purpose_ by the admins,
>   which is read as entirely for the benefit of the players (or as
>   a prop to some quest).  

That's one possible definition of purpose.  It ignores the case of
the NPC embodying or carrying out a purpose which is not related to
either direct game actions or players.  ie, their purposes, if
determined by a player, will be seen as incidental outgrowths of the
game, and which are also credible within the game milieu.

>   By purpose I mean, the NPCs have a place in the world, some kind
>   of role they play there outside of the players. Take a town
>   guard, for example. If all the guard does is automagically sense
>   player-committed crimes and arrive at the scene ready to
>   slay. The 'purpose' of such a guard is readily guessable by the
>   players, and is rightly seen as fake or tasteless. However, take
>   a different town guard who leaves the barraks at a scheduled
>   time, patrols the streets, fights off intruding monsters
>   crawling out of the sewer, stops player crimes, stops _NPC_
>   crimes (like a mob pickpocket, for example), takes lunch breaks,
>   and if killed, will be missed at the barraks, and will have his
>   name inscribed on the wall along with the rest of the town's
>   brave defenders. What a difference (and without stretching
>   current AI techniques)! This second guard has a _purpose_, a
>   place in town, he's not just a prop but now a proper inhabitant.

What about a guard who:

  Always wears a red string necklace, limps slightly favouring his
  left leg and wears the boot rolled down on that leg. Regularly
  accepts bribes from madams, but is unequivocably ferocious with
  prostitutes and pick pockets.  Seems to have a soft spot for
  flower stalls.  For some reason one of the stall vendors, and it
  varies as to which, gives him a bunch of flowers every week.  Its
  not clear why they give them (they are expensive), or what
  determines which vendor will give them.  He always graciously
  thanks them resulting in both sides smiling and bowing.  Its also
  not clear why he accepts them or what he does with them, except
  that he's been occasionally known to peel off a flower and give it
  to a madam, who for some reason is then usually very flustered.

> Motivation is a related concept. Even the _illusion_ of motivation
> is sometimes enough! Give some sense of internal motivation to
> your NPCs and monsters, from self-preservation, to greed, to
> simple kindness.

Why so coarse and base?  Why not motivate in more realistic manners

  He's saving to build a wall around his wife's garden as a present.

  His kid's leg was broken by an outsider mercenary who then
  vanished.  This fact is neither easily determinable or necessarily
  exposed by the game, but it results in that guard being
  considerably rougher on taller blonde mercenaries, or in fact any
  tall blond with scars.

>   - Complexity. I think this mysterious quality of the kinds of
>   NPCs JC was talking about is an emergent property, something
>   that comes with a sufficient level of complexity.

It can be emergent.  I don't think it necessarily is.  The Cheshire
Cat is quite simplisitic.

>   What kind of complexity? Motivation is one axis of complexity,
>   ranging from a sewer slime who mindlessly gobbles all in its
>   path, to a raven who gobbles, looks for mates, steals shiny
>   objects and has a sense of self-preservation, to the
>   aforementioned town guard, who has all the previous motivations,
>   plus that of guarding the town and even gambling on the side.

I'd say that the visible effects of customised/personal value
judgements are the most telling criteria.  Bubba is a character not
because he is different, but because he visibly make decisions on
personal criteria and value assignments which are unique (in some
sense or flavour) to him.

>   Interaction is another axis - it's not enough to just interact
>   with both world and player (as in the previous point), but
>   interact in how many ways?  Can the NPC be attacked and killed? 
>   Does it have valuables to be stolen? How about secrets, which a
>   mind-reading mage can discover? Can he/she be hired?  Offended
>   or befriended? Will it pass along rumours to other NPCs? Scream
>   for help or yell encouragements? And so on. In general, the
>   complexity of an NPC's internal programming, for whatever
>   purpose, falls under this category.


This tend to be the sort of thing that annoys me in NPCs as its just
layer of mechanical feedback mechanisms.  Its now not just a
shopkeeper it has other buttons as well, which when pushed, will
pre-deterministically and repeatably generate the same results.

Even a trained dog is less mechanically deterministic and
predictable than this.

>   - Detail. This is different from complexity. How many loving
> details does an NPC have, whether hand-coded or automatically
> generated from a well-put-together algorithm? Accents, mannerisms,
> scars, tears in clothing, signature actions (phrases, spells,
> combat moves), unique equipment, phobias -- the list goes on
> forever. Even a detailed description can go a long way towards
> this (and again we cross into the realm of the literary).

Taking the example guard I wrote about above, and his red string
necklace and left leg favouring, I find the fact of those
characteristics utterly uninteresting.  What is interesting is that
there may be a reason (and in fact there is), and that reason and
its implications on the guards observed behaviour and purpose
patterns __may__ be partially determinable by a player.

For the same reasons however I'm much more tempted to do away with
such mass populous NPCs entirely.  Make NPCs rare signature LEDOs.

J C Lawrence
---------(*)                Satan, oscillate my metallic sonatas.
claw at kanga.nu               He lived as a devil, eh?
http://www.kanga.nu/~claw/  Evil is a name of a foeman, as I live.
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