achievable goals for NPC design

16 views
Skip to first unread message

Steven Grady

unread,
Mar 8, 1994, 5:08:42 PM3/8/94
to
One thing that struck me about Alone In The Dark (which I alluded
to in an earlier post) is that the NPCs are simply monsters which
attack in an unintelligent fashion, yet their repetitiveness is
not annoying (although they're fearsomeness can be frustrating).
I think the reason is that because they are monsters, we have no
expectation of intelligent bahavior from them, and furthermore, within
the context of the game (a horror scenario inspired by Lovecraft's
works) such intelligent nightmares are appropriate. The great thing
the designers came up with was an environment in which the NPCs,
limited by the current state of AI, were still acecptable. And I
think this might be a worthwhile area to consider for game design.

For instance, unless one wants to implement a full-scale natural
knowledge processor and generator, there are not many options for
handling dialogue with NPCs. One is to provide menus of possible
phrases (which I found extremely annoying). Another is to do as in a
game which I read a recent review of, which had a menu of attitudes
(e.g. speak threateningly, graciously, bluntly), which is a nice
improvement, but still quite limited. Or you can use keyword search,
which is useful, but pretty easily reaches the limit of simulated
understanding, and as such can also get annoying. I'm sure there are
many other approaches one can take.

Another option is to acknowledge that it's a lot of work to implement
true NLP (and the state of the art is still pretty bad, I'm led to
understand), so it's better to avoid it altogether. Dialogue could be
eliminated (easy, but limiting and unrealistic), or NPCs could be
eliminated (not too bad if there are a sufficient number of PCs in a
networked environment). But it's strikes me as very elegant to come up
with an NPC conception in which it make sense that the character can't
understand or speak. For instance, an illiterate deaf-mute would not
be expected to be able to communicate in anything but gestures and
actions. Such a character could probably seem reasonable in the right
environment (e.g. a warrior in a barbaric culture, or a child raised by
wolves). The nice thing about such NPCs is that when a player
encounters them, they will never be frustrated by the limitations of
the parser/AI-engine/whatever. It will just be an appropriate aspect
of the character.

The point is to come up with NPCs that are justified in their limited
abilities. The monsters in Alone In The Dark take that to an extreme
-- "we're not going to do AI at all, so let's use NPCs which no one
would expect to be intelligent", and therefore "let's use an scenario
(horror) in which unintelligent NPCs are expected". Other
possibilities include: young child, stupid robot, someone who is
psychotic, or long-lived alien for an NPC without the ability to make
plans; an amnesiac, an absent-minded professor, or just someone with a
lot on their mind for an NPC without a dynamic knowledge database; even
a robot or zombie for an NPC with a fixed set of actions. The point is
that it should fall on the designer's shoulders to promote the
suspension of disbelief, not on the players' to simply accept any
unrealistic or unplayable environment they are thrown into.

There's certainly a lot of room for creativity here (not to mention
humor). I think that for a designer who chooses not to solve the
toughest NPC AI problems, it's worth putting some effort into making the
game comfortable nonetheless.
--
Steven
Senators, TV Crews, and the nation in general are mystified when,
on the third day, Flaming Carrot shows a STAR TREK BLOOPER REEL
on behalf of the defense.

Duane D Morin

unread,
Mar 8, 1994, 8:40:37 PM3/8/94
to
In article <grady.7...@xcf.berkeley.edu>,

Steven Grady <gr...@xcf.berkeley.edu> wrote:
>For instance, unless one wants to implement a full-scale natural
>knowledge processor and generator, there are not many options for
>handling dialogue with NPCs. One is to provide menus of possible
>phrases (which I found extremely annoying). Another is to do as in a
>game which I read a recent review of, which had a menu of attitudes
>(e.g. speak threateningly, graciously, bluntly), which is a nice
>improvement, but still quite limited. Or you can use keyword search,
>which is useful, but pretty easily reaches the limit of simulated
>understanding, and as such can also get annoying. I'm sure there are
>many other approaches one can take.

A brief thread on "Foreign Languages in IF" touched a few of these issues,
after the idea was raised to have NPCs speaking in some manufactured
language, such as "Dwarfish", that could be easily parsed. [Hey, waitaminute..
I started that thread. :-)] But, as pointed out, NLP is NLP, and you're
either giving the user a subset of the language or not. The question then
becomes how useful of a subset you've got - do you create an NPC where
the subset makes sense (like your examples below), or do you just fix it
so that the user doesn't expect to be able to get very complicated.
(The thread rapidly turned into a discussion of the merits of Lucasgames,
and then into a discussion on Undo and other metacommands.)

>Another option is to acknowledge that it's a lot of work to implement
>true NLP (and the state of the art is still pretty bad, I'm led to
>understand), so it's better to avoid it altogether. Dialogue could be
>eliminated (easy, but limiting and unrealistic), or NPCs could be
>eliminated (not too bad if there are a sufficient number of PCs in a
>networked environment). But it's strikes me as very elegant to come up
>with an NPC conception in which it make sense that the character can't
>understand or speak. For instance, an illiterate deaf-mute would not
>be expected to be able to communicate in anything but gestures and
>actions. Such a character could probably seem reasonable in the right
>environment (e.g. a warrior in a barbaric culture, or a child raised by
>wolves).

For a character or two, sure, this would be ok, but I think the players would
rapidly get bored with it, and hope to find someone that they could hold
a better conversation with. One has to ask, though, other than ordering
an NPC to do something or asking the NPC about a particular subject, just
how much conversation can you have?

>The nice thing about such NPCs is that when a player
>encounters them, they will never be frustrated by the limitations of
>the parser/AI-engine/whatever. It will just be an appropriate aspect
>of the character.

I've entertained the idea of letting NPC's talk to each other. I mean,
it would be a sort of weird, virtual turing test - would either NPC be
able to tell that it was speaking to another NPC? NPC's, by their nature,
would have a limited set of sentence structures with which to form
sentences. Therefore, they could also be programmed to parse those
sentences intelligently. Whammo, create some sort of environment for this
to work in, and you've solved another piece of the "NPC who could solve
the game just as well as a human" - the NPC can run around and converse
with other NPCs.

> Steven
>Senators, TV Crews, and the nation in general are mystified when,
>on the third day, Flaming Carrot shows a STAR TREK BLOOPER REEL
>on behalf of the defense.

Duane

Reply all
Reply to author
Forward
0 new messages