[MUD-Dev] Player Manipulation of Environment

Hans-Henrik Staerfeldt hhs at cbs.dtu.dk
Tue Dec 4 15:01:21 New Zealand Daylight Time 2001


On Mon, 3 Dec 2001, Paul Schwanz wrote:
> Jasper McChesney wrote:
>> Paul Schwanz wrote:

>>> When it comes to responding to extremes in animal populations,
>>> however, I don't think we are limited to simply increasing spawn
>>> rates.  While I haven't fully fleshed out the idea, I lean
>>> toward having various "genes" that automatically respond to
>>> player actions in a way that functions something like a crude
>>> sort of natural selection.  This is off-the-cuff, but I'll give
>>> a simple example.

>> I'm a great fan of ALife, and think such models would be really
>> interesting if implemented in an online world.  I have to
>> question though, whether it's really a very useful thing to do.
>> At the most basic level, you'd be devoting a fair amount of CPU
>> cycles to determining a lot of things that would be entirely in
>> the background and probably never surface to player view.
>> Natural (or unnatural) selection allows an organism to adapt to
>> its environment -- i.e.  survive better.  Unless your MUD really
>> needs rabits to survive better, I think it's a lot of work for
>> not much reward.  I guess you may indeed want better rabbits just
>> to keep the population alive but to what end?  You'll have a lot
>> of imbalances if monsters start getting tougher and tougher as
>> the game goes on.  You always (and I'm speaking with the general
>> "you" here) have to be aware that allowing a large subsystem of
>> your game to "evolve" freely could potentially change the game
>> environment a lot. (If it can't, what's the point?)

> Well, since the whole point of the post was to address the
> possibility of avoiding rabbit extinction, it is the case that we
> really need rabbits to survive better, especially at population
> extremes.  We'd like to keep the population alive, so that the
> content we've created (rabbits) is not completely removed from the
> game by player actions.

> The system is not designed so that monsters get tougher and
> tougher as the game goes on.  Rather, it is designed to have a
> monster get "tougher and tougher" as that monster's population
> levels reach a lower extreme.  At least, that is the goal of the
> design.  If the former instead of the latter will be the practical
> outcome of the system as it stands currently, I'd be happy to have
> this illustrated so that I can work to tweak the design.

<mudstyle=hacknslash>
  I fear that there is a problem in the system, and that is that you
  risk making a particular group extinct; the players. As others
  have stated it is important to assign a 'cost' to the abilities.

  It is also important to try and vary more than a few things. This
  is because you need the population to break up and develop new
  subraces. This is important because you risk that the population
  gets pushed in front of the higher level players. Say you only
  have rabbits. And the steadily increasing playerlevels makes them
  impossible opponents for lower level players. Therefore the cost
  function must also modifications to the gain the players get
  (exp,loot etc.). This would allow a new race of lowlevel-lowexp
  rabbits to break off the genepool and find a niche where they are
  only hunted by the low levels. If you would allow for 'costless'
  modifications to all stats, you would end up with super tough
  low-exp rabbits, and a player base that would go nowhere. Hardly
  fun at all (well i'm laughing but, he he, i would not be playing
  it much).
</mudstyle>

<tech>
  I don't think that the CPU load would be too great. It depends on
  your 'environmental' model. How advanced is your evaluation if a
  rabbit may give birth?
</tech>

>> With this setup, I can look at any rabbits with the same "dominant
>> gene" and myself determine which is better -- no simulation
>> required.  Having "more pronounced" versiouns of each dominant
>> gene seems pointless to me, or at least less interesting than
>> other options, since the lesser forms are always worse.  It's liek
>> being given the choice between the shotgun and the super-shotgun
>> in Quake on the later levels -- why even choose the former (I
>> know, there are reasons -- not the best example).

> The more pronounced versions are there to respond more
> dramatically when populations are experiencing extremes in
> pressure.  Their function is to help avoid extinction and not so
> much to provide some sort of "neato" interest to players...at
> least not directly.

I would use the function 'to duplicate' a gene to make it more
pronounced as a possible mutation.

I just saw some new results from genetic diversity in hepatitis B
virus in patients that were treated. The variability goes up as soon
as the preassure (treatment here) is on.

>> Secondly, and more problematic, is the fact that your traits are
>> numeric in nature and not binary switches.  If I ran it now, I'd
>> soon enough have rabbits that became better and better: their
>> trait rating would continue to rise unchecked.  Eventually, you'd
>> have 100% invivisble rabbits -- or whatever other ceiling you
>> establish.  The problem is that there's no disadvantage to
>> becoming specialized here: no complex interaction between genes.

> You will only have 100% invisible rabbits (overlooking the fact
> that this conflates fittest with fit enough--in reality, the fit
> enough survive) until the next generation, where (with the
> specific numbers I used to explain the concept) you'd have only
> 80% invisible rabbits.

<mudstyle=hacknslash>
  One cost could simply be the experience award. The more fit they
  are the more attractive they are.
</mudstyle>

>> At a minimum, you don't simply want a "dominant gene" but rather
>> a total balance between traits.  If a rabbit gets better at
>> stealth, its other abilities should suffer.

> A rabbit can only get better at stealth by not having the other
> traits.  So, its other abilities do suffer.  The rabbit that has
> the camouflage trait cannot also have either the higher hit point
> trait or the faster birth rate trait.  The confusion is probably
> my lack of knowledge concerning the terms used in real scientific
> study in this area.  Obviously, my original post wasn't very
> clear.

> To explain further, what I meant by a particular gene being
> dominant is that, although the other genes can be passed along to
> offspring, they are not in any way active in the current rabbit.
> Only the "dominant" gene is active.  A rabbit that has the
> camouflage gene active has a set amount of hit points.  Its
> offspring's hit points will only be higher if the offspring takes
> the higher hitpoint trait/gene instead of the same or better
> camouflage trait/gene.  In this sense, it is a sort of "either-or"
> proposition.  I think this is what you meant by "binary" above.

If you do not let the rabbit 'truly' evolve but limit them to have
only one gene dominant, i feel you fall short of the potential here.
I would rather use the system to evolve races that fitted the
current player population level/skill distribution.

> I'm not sure I'm understanding.  It seems to me that you are again
> overlooking the possibility that a rabbit will be fit enough even
> if it is not the fittest.  Also, provided your game area is large
> enough and your birth rate numbers are in the right balance, I
> would think that players would be more than likely to abandon a
> hunting zone where rabbits were very hard to find in favor of one
> where rabbits are much easier to find.  In fact, I'm pretty sure
> that someone posted some behavioral information a while back which
> discussed the fact that players would automatically distribute
> themselves in a manner which is very closely related to the amount
> of rabbits (cheese) available at different locations.

I think that you simply need more genes to make your point better.

   A damage gene.
   A extra attack gene (bite, etc).
   A speed gene.
   An agressive gene.
   A flee gene.
   A size gene.
   A magic gene for spell XX.
   A weaponuser gene.
   A item gene (example; carries a sword).
   A magic resistance gene.
   A good hide gene (armor+price).

I would say that for this to work, they should not be excluding
eachother (at least not all).

>>> If the area has no other natural rabbit predators, the rabbits
>>> with higher birth rates will tend to be most prevalent in an
>>> unhunted area.  On the other hand, if predators are predisposed
>>> to eat rabbits with lower hit points, then rabbits with the
>>> h-gene may predominate.

>> This is the most intersting part of your (specific) scheme:
>> seeing what rabbit-type becomes dominant in a given area.  I
>> still don't know what game purpose this really serves though.

> The rabbits are responding to pressures that are in their
> environment with the goal that they remain fit enough for the
> rabbit population to survive.

> Well, perhaps that is the next step in making things more
> interesting.  (My fist concern, though, is the survivability of
> content where players are given additional freedom to interact
> with content.)  It might be possible to have multiple genes at
> work simultaneously in the same rabbit.  The case you describe,
> however, seems to go contrary to the whole point of my post.  I
> want breeder rabbits to be more survivable in certain
> circumstances than other types of rabbits, just like the other
> types of rabbits are more survivable in other environments.  If we
> make it so that the pelts of breeder rabbits are also much more
> valuable, it tends to undermine the whole point of the excercise.

Well the farmer will try and kill off any freaks. In short if its
not a breeder rabbit with good fur, it don't get to procreate, you
die (given the player can observe this). After while, the entire
population would be good fur breeder rabbits, increasing the
probability of getting more of these, and this the profittability of
the farmer.

> My goal was to keep rabbits alive for the sake of maintaining an
> ecosystem in which players can effect and experience changes.

I would use it to develop the new races needed to support my
hacknslash players. The hard part would be to make the experience
evaluation function for a given set of genes. But potentially you
could get the population to split off into other races, and fill in
niches of the game. You should perhaps have a warning system,
telling you that the 10 ft. tall, green scaled firebreathing thing
living in a cave is a tad genetically different from what you
originally called a 'rabbit'.

Hans Henrik Stærfeldt   |    bombman at diku.dk    | work:  hhs at cbs.dtu.dk      |
Address:                |___  +45 40383492    __|__       +45 45252425     __|
DTU, Kemitorvet,        | Scientific programmer at Center for Biological     |
bygn 208, CBS.          |  Sequence Analysis, Technical University of Denmark|

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