NPC Behavior

The Reindeer Effect · 2004-11-21T10:11:13

I have lately been thinking alot about game design, that of non-player characters in particular. Namely, the issue of creating a model that provides for realistic, dynamic behavior. I'm going to jump right into the current system I have been invisioning .... For personality, I think the best course of action would be something like a Myers-Briggs Type Indicator . Rather then locking it into explicit categories, I feel the proper course of action would be to lock each variable into a range, therefore we could represent an individual who is slightly introverted, rather than extremely introverted. However, MBTI alone is not enough to represent the personality. Two (and there are likely others) that I feel will influence the behavior of the NPC are Bartle type (I realize that this system refers to people who play MUDs ... but NPCs are intended to be seamless and I believe their actions are highly influenced by this system) and alignment (not in the sense of karma, but rather the players natural inclination towards good or evil). Now I understand that there is some overlap here, and probably missing elements, but until I read up some more, I will leave it as is. Beyond the personality, we have mood. A player's personality is somewhat abstract; although it influences his behavior, it takes into account no external stimuli (I am not ballsy enough to try and design dynamic personality, although I am sure it can be done). The mood, however, is the personality's response to the environment. An INTJ evil killer's mood would almost undoubtedly respond different to the murder of his mother than that of an ESFP good socialiser. Exactly how the mood responds I have yet to work out. In fact, I haven't even discovered how to represent the mood. There are many elements, and their relationships are quite unusual. A player who is happy is by definition not sad. A happy player is also not angry. However, an angry player can be neutral (neither sad nor happy, just angry) or angry and sad. Not to mention I am not confident in my current classification of mood types either ... I feel I have grossly under-represented the mood. The player also has certain attributes which define his capabilities in the world. This is your bread-and-butter off most RPGs ... the STR/AGI/CON/DEX/INT/WIS/CHA combo. There is a question of whether some of the personality based attributes (Charisma and to a certain extent, Wisdom) have a place, given the MBTI. To that, I have no answer as of yet, so I have chosen to include them for completeness. Although these attributes have a great influence on gameplay dynamics (damage done, chance to block, spell success, whatever), they seem to offer little value to behavior. As well, these are static in nature. Although they can be developed as the player develops, attributes such as these are not really derivatives of others (whereas mood is derived from personality), nor are there any external inputs. So now, we come to behavior. Some behavior (pathfinding mechanics) is rather trivial, and is not influenced by the developed model. However, higher level behavior would be strongly influenced by this model. In fact (ideally), every player action would be the result of applying the environment to the personality/mood combination. In essence, personality + environment -> mood mood + environment -> behavior The scope of the behavior is based upon the character's physical attributes. If a character with low strength is enraged to the point of attacking another character, he may throw a rock at the enemy. An exceptionally strong character may throw the enemy at a rock. Either way, the combination of his mood (infuriated) and the presence of a character who he feels hostile to (environment) leads to him physically attacking the player. Moreover, a merchant who travels from one town to another, trading goods for a profit, has a naturally ambitious personality. If he discovers he can sell items for more profit at a town other than his destination, he will be likely to travel there (assuming he is adventurous enough, and with a capable constitution to survive the journey). In this case, behavior is based little on mood, but this is a situation in which the NPC is not giving an emotional response, therefore personality plays a stronger role. I hope I'm not just rambling now. This post may be a little rough; excuse me, I have class in 5 minutes and as such am forced to cut it short. However, I would appreciate responses to what I wrote, and corrections are even more appreciated. Thanks.

Game Design and Theory Game Design

Started by The Reindeer Effect November 17, 2004 10:53 AM

11 comments, last by GameDev.net 20 years, 2 months ago

Heaven

601

November 19, 2004 11:08 PM

I think it'd be a good starting point to design a small village. Take a dozen or a score of NPCs, assign them different professions, and program them to be self sufficient (or nearly so).

You'd have mostly farmers, a blacksmith, maybe an innkeeper, and of course the village leader, all with associated familial attachments (i.e., spouse, children, dog and cat, etc.)

Each one should have Home and Work places, and each should have a default daily routine.

Just some thoughts.

Take care.

Florida, USA
Current Project
Jesus is LORD!

NPC Behavior

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NPC Behavior

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