[Bjorn]

[PhyrFox]

Greetings.

First of all, I am new here, but I thought I'd throw in my two cents regarding this rather interesting topic. There's an idea that I've read about that would greatly improve the theories presented by the other posts here. Feel free to use or ignore the idea, as you will.

I have several game design books, and inevitably, they cover the topic of AI. Specifically, how to make customized NPCs seem more realistic. Here's a few ideas that you might use, as paraphrased from the book "Game Design: Secret of the Sages" (if my memory serves me correctly).

It was stated in this useful book that a NPC or enemy (whatever) could have a set of associated weights and/or genes. Weights determine the probability of a given character saying or doing something based on what they've "learned" or due to various "personality" quirks. In the book, it goes to say that an AI of a fighter pilot in a dog fight versus the player would try a more favorable attack method (roll, scissor, loop-de-loop, etc) based on the successfulness of previous attacks of that type.

A success would increase the weight (and thus, the probability that it would use that action in the future), whereas a failure would decrease its usage. To apply a personality quirk, simply adjust the amount that a weight is adjusted by (for example, if a NPC really enjoys using loop-de-loops, a failed action would decrease the weight by 1% instead of 10%, or something).

This might be useful in having the NPCs react to a player in an RPG based on previous dialogs (for example, when you give them an item they "like" or say something to "offend" them). This idea has been used in many games, really, from FFVII, to Morrowind, and so many others. Although generally, they used less-defined methods, such as "How many times did the player let hero X die?", or "How often was a combination of heroes in a party?"

The other idea was the use of "genes," a "genetic pool" of abilities or attributes that would be assigned to a NPC that would affect how they act. Examples might be "sneaky," "greedy," "friendly," or any other attributes you might think of. In the book, they used it as a method of determining how AI-controlled bots would attack you in Halo. In this context, you might use genes to determine the initial responses that the player would get from interacting with an NPC, and further adjust the weights mentioned above similar to "personality quirks." The only difference here is that they are dynamic changes instead of "static" changes, such as above, where specific NPCs were hard-coded to change their weights by who they were, instead of randomly assigning personality traits.

Genes could be populated from a "gene pool", thus ensuring that only a certain population percentage would have the traits, absolutely guaranteeing a variety of characters in different places every game. The gene pool could be global, by area, or any other way you might divest them.

This is, of course, all just vague, but if anyone sends me a message, I'd be glad to help out with more specific examples, or I could help whoever needs help coding some of this stuff. I've got plenty of free time. Anyway, must be going, but I'll be back later.

--Fox--

[Hajo]

Hi,

I've just released a very first version of my space exploration game.

Look here:
http://www.simugraph.com/forum/viewtopic.php?id=11&t_id=32

Maybe you can install "Arxigle Xentrophore" (needs the base package and engine instralled also), and take a look at the space station.

There are a number of NPCs on deck 1 of the space station (the one above the hangar). Some are traders, one shall become a public officer who hands out mining licences and there is a bar. Also some other space station inhabitants that don't have a well defined role currently.

Maybe you can explain your ideas using them as examples?

Currently all space stations in the game are 100% identical. There is an almost unlimited number of solar systems. The problem is how to create different NPCs for all the stations. I think it's ok that the station have the same level layout, we can assume they are build from mass-produced modules that are always the same (I'll introduce a few basic station types to get a little of variety, but that's not a problem).

It would be nice if the NPC could talk about things that are specific to their solar system or environment. Moreover, I'd really appreciate if all NPCs would have individuel dialogs.

[PhyrFox]

[Hajo]

[PhyrFox]

For a rather complex-looking (but should be rather simple) system, I'd try something like this:

1) Choose Race or Class, select a topic.

This will be the basis of their conversation. They might choose a topic such as "homeworld," "profession," "family," or some other major topic.

2) Choose more specific details.

Depending on what group they are talking about, have the speaker choose a specific topic item, maybe an item, creature, or something. Could apply to a possible event (as something that has, or could, happen).

3) Apply genes to dialog.

So, they are now talking about a subject in light of a specific "mode of thinking." You could add/change phrase groups to fit a particular gene. For example, a greedy gene would show it's ugly face whenever a NPC discusses an item they'd *love* to have.

4) Construct dialog sentence(s).

Now you have the basic phase groups. Each group is based on the subject they are talking about, and in reference to the "relationship" to the thing they are talking about. Within the group there are various phrases that *could* be said. The more groups or "fragment families" you have, the more the dialog sounds normal (or at least, a lot less like pre-gen talk). Having a reasonable amount of fragments in each "fragment family" would keep the dialog fresh.

5) Translate to native talk per race/class.

This extra step might translate "You" into "Y'all", or "Goodbye" to "Laters" or "See ya around" based on a table that would contain basically "grep()" commands to change the text further, so that it would further customize the dialog based on perhaps their race (they expand the 's' sound) or they talk as a younger/older generation, or they have odd sayings unique to their culture or profession. Possibilities are near-endless on this.

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Alright, so that ended up different than my previous idea. My idea seems to be evolving differently the more I think about it. Sounds much like the problem you're having, not knowing how to express yourself (pun intended). But you could just as easily start off with Genes first (choose a "madlib" series to fill in) and fill in the blanks, then translate. Goodness. All this typing about it makes me want to try my hand at making something like this. I'll see if I can post something near the end of the week to this effect.

As for making dialog boxes that have responses (now that I've had a chance to actually play the game), I'd recommend possibly not having any useful responses to most of the dialog boxes (because, AI only looks intelligent for so long), or have them have a set of response dialogs depending on the situation (if they choose an event, ask the player what s/he thinks, or if it's a story, the player may choose to act interested or not, etc). Then have them respond in kind to these responses much the same way (making fragment families for various positive and negative responses).

The only *final* alternative, if you really wanted to, would be to actually personify each NPC with an AI memory, and some sort of advanced AI chatting system (something like ALICE would be interesting to see in an engine), but those require programming neural networks, etc. I'd settle for having mostly not-repeated dialogs that are completely random, versus something that is quite a bit more repeated (like Morrowind... try it, you'll see what I mean).

~= PhyrFox =~