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Posts Tagged ‘Sims 3’

Dating Sims: A New Frontier for RPG AI?

Thursday, May 27th, 2010

It’s amazing what pops up in my daily Google Alerts for “game AI” (although I’m getting tired of Allen Iverson news). This one caught my eye, though. On a blog called “Win My Ex Back” (no thank you, by the way), there was a post titled Online Dating Sim Game. There wasn’t a lot of detail about a specific game other than to mention online that “dating simulation games are among the new genres of online gaming that depicts romance.” To give an idea of what the author (Andy Jill) has in mind, I quote his summary:

It’s a simulation game where the main character that you’ll play (commonly fictional characters) has to achieve specific goals. The most typical one is to date numerous and different women and to have high level of relationship and among them within specified time limit. Generally, the game character must have enough funds by either securing jobs or other income-generating activities such as business.

In the same manner, attributes of the character is important in the game. Such attributes can be improved by doing different task and accomplishing it within the time limit. Most of these tasks take time to be accomplished and games of this type have real-time to them.

The author goes on to describe what apparently was the first online dating Sim, “the Dokyusei or Classmates” from 1992. Again to quote:

In this classic dating sim game, you will be controlling a male avatar that is surrounded by various female game characters. The game play will involve conversations with a variety of artificial intelligence (AI)-controlled girls, in which you will attempt to increase your “internal love meter” by means of right choices of dialogues. The game usually last for a limited game time like a month or a year.

Once the game is finished, your character may lose the game if it failed to win the hearts of any girl. However, you may “finish” one or more girls, usually by having sex with them or by attaining eternal love.

18 years later and we are still relegated to dialog trees.

To me, this sounds like the Sims titles… or for that matter, how some people try to play Mass Effect 2. Anyway, the point is not the gameplay mechanism (which is somewhat standard). Even the personality and mood meter facets are not all that uncommon. Again, think Sims 3. What I find almost joltingly alarming is that this game from 1992 was based on a dialog tree. Sure, that’s fine. We’ve had dialog trees for a while. The problem is… that’s how we would still have to do things! 18 years later and we are still relegated to dialog trees.

The only reason that the Sims doesn’t have dialog trees is that there isn’t real “dialog”. At least not the intelligible sort. Sure, there are behavior selection trees for choosing what to do next, but there is a subtle difference. When you select an action in the Sims, the game designer hasn’t necessarily hand-crafted what the response (or potential responses) will be. In a dialog tree, you are always in a specific place in that tree until you exit it. In the Sims, all that happens when you select an action is that you vaguely change the internal state of the character you are interacting with. That character’s actual response is calculated in a ridiculously expansive set of state values, formulas, and then a stochastic factor tossed in for good measure. You aren’t really ever sure exactly what you are going to get… although you may have a good idea what it might be.

On the user input level, it is still reminiscent of Zork or the early Ultima games.

I have to assume that this dating sim — and all others like it — would rely on a representation of actual dialog, however. And that brings us back to the dialog tree. Natural language processing isn’t going to cut it. Emily Short does a good job of it in her interactive fiction but the root of it all is still keyword-based input. As amazing as her work is, on the user input level, it is still reminiscent of Zork or the early Ultima games. Translated into a dating sim, the user’s free-form input could very well be reduced to “ask job”, “tell age”, and “compliment boobs”. In effect, it wouldn’t be all that different than the chat room shorthand of “a/s/l” for “age/sex/location”. Even if the game then gave elaborate (yet pre-scripted) answers to your questions, it will still be annoying to have it reply “I don’t understand what you mean” when you don’t guess the right keywords to use. Additionally, using that sort of shorthand isn’t going to ever feel really “romantic” is it?

I’m halfway through Noah Wardrip-Fruin’s book, Expressive Processing, where he talks extensively about the history and state of interactive dialog and drama. Even with all the work that has gone into this field for over 40 years, I’m sorry to say that we are no where near being able to replicate something other than a stilted parody of a romantic courtship.

That being said, it doesn’t matter how deep the AI is behind the scenes. Until we can solve the input/output problem our AI is trapped inside itself. Animation has gotten a lot better of late—especially facial and speech animation. I know there are adult-themed games out there and I assume that they are taking full advantage of photo-realism (not to mention realistic physics). However, all that nifty facial animation and subtle gesturing would still have to be tied to canned, pre-written dialog. And that is our bottleneck, isn’t it?

I don’t know how to solve it, really. Noah’s book is my first foray into even thinking about this interactive dialog and fiction stuff. (On the other hand, I would be tickled to do the personality, mood, and emotion modeling. That is in my wheelhouse!) That said, I don’t know how to solve it. I just find it sad that we are still stuck in this world where we can’t really interact with our game characters on a meaningful, natural-feeling level. I do know, however, that when we find it, that will be one of the final cusps we need to cross over in games. At that point, there’s not a lot stopping us.

AIIDE 2009 – AI Challenges in Sims 3 – Richard Evans

Thursday, October 29th, 2009
This is the rough dump of my notes from Richard Evans’ AIIDE 2009 invited talk on the AI challenges they faced in developing The Sims 3. Some of it was familiar to me as being exactly what he presented as part of our joint lecture at the GDC AI Summit in 2009. Other portions of it were new.

Specifically, I enjoyed seeing more about how they handled some of the LOD options. For example, rather than parsing all the available actions, a sim would decide what lot to go to, then what sim to interact with, and then how to interact. Therefore, the branching factor was significantly more manageable.

Another way they dealt with LOD was in the non-played Sims. Rather than modeling exactly what they were doing when (while off-screen), they made some general assumptions about their need for food, rest, taking a leak, etc. These were modeled as “auto-satisfy” functions. For example, if you met a sim close to dinner time, he would likely be hungry. If you met him a little later, he would present as being full.
Additionally, as you will see below, the entire town had underlying simulation mechanics that balanced how many people were dying and being born, what gender they were (on average), and even where they were moving to and from. They modeled much of this with a very simple geometric interface early on so that they could test their mathematical models. Same with the simple behaviors. He showed video demos of these models in action. This also allowed them to speed up time to ridiculous levels and let the sim run overnight to test for situations that would tip the sim out of balance. Lots of fun!
He also mentioned about how the behavior selection was done. This was important to me in that he showed how they used some of the same techniques that I talk about in my book. Specifically, he uses a utility-based method and selects from the behaviors using weighted randoms of the top n selections. Excellent work, sir!
The following are my raw notes.
AI Challenges in Sims 3
Richard Evans
He mentioned the website dedicated to Alice and Kev. The author simply sat back and watched the Sims do their autonomous behavior and wrote about it.
1. Hierarchical Planning
2. Commodity-Interaction Maps
3. Auto-satisfy curves
4. Story progression
Instead of nesting decisions about which act to perform on which person in which lot, you chose a lot first, then chose a person, then chose an action.
O(P + Q + N) instead of O(P * Q * N)
Data-driven approach so that the venues populate appropriately (e.g. restaurants)
Optimization
If you are full, don’t even consider eating as a possible selection of what to do.
Auto-satisfy curves for LOD. That way you don’t have to simulate the off-screen Sims. Assume that they have eaten at the right times, etc.
Other Sims need to progress through life the same way that your Sim does. Age, marriage, children, career, move, etc. Long-term life-actions are simulated at LOD.

The town has various meta-level desires. (Gender balance so that we don’t have all male or all female.) (Employment rate for the entire town. Some people will be unemployed… peaks at ~80-90%
High-level prototype showing the major life actions (not smaller actions). Simulating the town without simulating the people.
Making Sims looking after themselves

Utility modeling
Highest-scoring
Randomly from the n highest-scoring actions
Randomly using the score distribution as the probably distribution (weighted randoms)
Personality and Traits and Motives
Same that he talked about at AI Summit
Traits -> Actions = massively data-driven system to minimize hard-coded systems.
Kant’s categorical imperatives?!?
Emily Short: “The conversation is an end in itself.”
Take Home Actionable items
Data-drive everything!
Take the teime to make good in-game viz. tools
Prove out all simulation ideas using prototypes as soon as possible.
Richard shows excellent 2-D prototype that runs sims without the realistic world!
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