Enemy NPC Design Patterns in Shooter Games

Advances in Computer Entertainment Technology

Domain-Specific Modeling (DSM) has shown its effectiveness of improving software productivity in many software domains [1], where Domain Specific Language (DSL) plays a key role. Also in the domain of video games, researchers have proposed various DSLs for developing different aspects of several game genres. This paper presents a DSL named RAIL for generating Non-Playable Character (NPC) behaviors in Action/Adventure Games. Our DSL borrows concepts from State Machines and adds some features to better suit the target domain. Further, we have implemented a tool-chain for RAIL using the Eclipse language workbench, and the tool-chain has been integrated with the level editor of the Torque2D game engine. To evaluate the DSL, we developed a prototype game and collected data regarding the development time and code lines. The results showed that RAIL significantly improves the productivity of developing NPC behaviors in the target game with a reasonable associated cost. In addition, the integration of the RAIL and the Torque 2D tool-chains provides a smooth development workflow.

IEEE Intelligent Systems, 2006

Many computer games use custom scripts to control the ambient behaviors of non-player characters (NPCs). Therefore, a story writer must write fragments of computer code for the hundreds or thousands of NPCs in the game world. The challenge is to create entertaining and non-repetitive behaviors for the NPCs without investing substantial programming effort to write custom non-trivial scripts for each NPC. Current computer games have simplistic ambient behaviors for NPCs; it is rare for NPCs to interact with each other. In this paper, we describe how generative behavior patterns can be used to quickly and reliably generate ambient behavior scripts that are more realistic, entertaining and non-repetitive, even for the more difficult case of interacting NPCs. We demonstrate this approach using BioWare Corp.'s Neverwinter Nights game. wake at dawn, walk to work, run errands, go home at night, and make random comments about the disposition and appearance of the PC. However, the behaviors and comments are "canned" and repetitive and NPCs never interact with each other. The Elder Scrolls 3: Morrowind (Bethesda Softworks) has a huge immersive world. However, NPCs either wander around areas on predefined paths or stand still, performing a simple animation, never interacting with each other and ignoring the simulated day. In The Sims 2 (Electronic Arts), players control the NPCs (Sims) by choosing their behaviors. Each Sim chooses its own behaviors using a motivational system if it is not told what to do. The ambient behaviors are impressive, but they hinge on a game model (simulation) that is integral to this game and not easily transferable to other game genres, including CRPGs. Halo 2 (Bungie) is a first person shooter with about 50 behaviors, including support for "joint behaviors" [1]. The Halo 2's general AI model is described, but no model for joint behaviors is given. Façade [2] has an excellent collaborative behavior model for NPCs, but there are only a few NPCs, so it is not clear if it will scale to thousands of ambient NPCs. They also comment about the amount of manual work that must be done by a writer when using their framework. Other research includes planning, PaTNets, sensorcontrol-action loops , and automata controlled by a universal stack-based control system for both low-level and high-level animation control, but not in the domain of commercial-scale computer games. However, planning is starting to be used in commercial computer games in the context of Unreal Tournament . Crowd control research involves low-level behaviors such as flocking and collisions and has recently been extended to a higher-level behavioral engine . Group behaviors provide a formal way to reason about joint plans, intentions and beliefs. Our approach is dictated by the practical requirements of commercial computer games. Our model is robust, flexible, extendable, and scalable [6] to thousands of ambient NPCs, while requiring minimal CPU resources. Moreover, our generative pattern abstraction shields story designers from manual scripting and the synchronization issues of collaborative behaviors, and allows them to concentrate on story construction.

Proc. Computer Game Design and Technology Workshop 2007, 2007

This paper explores how games can be designed to make the social networks of characters as part of the gameplay. We start with a premise that game characters and social relations between them are import in games. We examine several games and derive gameplay design patterns from those games. Models from social network analysis, actor-network theory and Egri's model for dramatic conflict is used to focus the analysis. In addition to isolating design patterns from existing features of the games, we look situations where ...

2014

This essay develops a method for the analysis of video game characters based on a theoretical understanding of their medium-specific representation and the mental processes involved in their intersubjective construction by video game players. We propose to distinguish, first, between narration, simulation, and communication as three modes of representation particularly salient for contemporary video games and the characters they represent, second, between narrative, ludic, and social experience as three ways in which players perceive video game characters and their representations, and, third, between three dimensions of video game characters as ‘intersubjective constructs’, which usually are to be analyzed not only as fictional beings with certain diegetic properties but also as game pieces with certain ludic properties and, in those cases in which they function as avatars in the social space of a multiplayer game, as representations of other players. Having established these basic distinctions, we proceed to analyze their realization and interrelation by reference to the character of Martin Walker from the third-person shooter Spec Ops: The Line (Yager Development 2012), the highly customizable player-controlled characters from the role-playing game The Elder Scrolls V: Skyrim (Bethesda 2011), and the complex multidimensional characters in the massively multiplayer online role-playing game Star Wars: The Old Republic (BioWare 2011-2014).

2008

Game metrical data are increasingly being used to enhance game testing and to inform game design. There are different approaches and techniques to gather the metrics data; however there seems to be a lack of frameworks to read and make sense of it. In this paper, the concept of play-persona is applied to game metrics, in the specific case of character-based computer games, where the player controls a single protagonist, around whom the gameplay and -story evolves. A case is presented for Hitman: Blood Money (IO Interactive, 2007). Player-controlled game characters can be deconstructed into a range of components and these expressed as monitored game metrics. These metrics can subsequently be utilized to discover patterns of play by building play-personas: Modeled representations of how players interact with the game. This process can also be useful to assist game design, by informing whether the game facilitates the specific play patterns implied by theoretical play-personas. of time spent running, vector of movement towards opponents. Frequency of climbing and falling. Frequency of lock shooting as opposed to lock-picking/key use.

2010

Abstract Level designers create gameplay through geometry, AI scripting, and item placement. There is little formal understanding of this process, but rather a large body of design lore and rules of thumb. As a result, there is no accepted common language for describing the building blocks of level design and the gameplay they create. This paper presents level design patterns for first-person shooter (FPS) games, providing cause-effect relationships between level design elements and gameplay.

2006

Many computer games use custom scripts to control the ambient behaviors of non-player characters (NPCs). Therefore, a story writer must write fragments of computer code for the hundreds or thousands of NPCs in the game world. The challenge is to create entertaining and non-repetitive behaviors for the NPCs without investing substantial programming effort to write custom non-trivial scripts for each NPC. Current computer games have simplistic ambient behaviors for NPCs; it is rare for NPCs to interact with each other. In this paper, we describe how generative behavior patterns can be used to quickly and reliably generate ambient behavior scripts that are more realistic, entertaining and non-repetitive, even for the more difficult case of interacting NPCs. We demonstrate this approach using BioWare Corp.'s Neverwinter Nights game.

2005

The current state-of-the-art in computer games is to manually script individual game objects to provide desired interactions for each game adventure. Our research has shown that a small set of parameterized patterns (commonly occurring scenarios) characterize most of the interactions used in game adventures. They can be used to specify and even generate the necessary scripts. A game adventure can be created at a higher level of abstraction so that team communication and coding errors are reduced. The cost of creating a pattern can be amortized over all of the times the pattern is used, within a single adventure, across a series of game adventures and across games of the same genre. We use the computer role-playing game (CRPG) genre as an exemplar and present a pattern catalog that supports most scenarios that arise in this genre. This pattern catalog has been used to generate ALL of the scripts for three classes of objects (placeables, doors and triggers) in BioWare Corp.'s popular Neverwinter Nights CRPG campaign adventure.

Proc. 3rd Digital Games Research Association International Conference, 2007

Descriptions of humans require several qualities for people to experience them as believable: human body; selfawareness, intentional states, and self impelled actions; expression of emotions; ability to use natural language; and persistent traits. Based on these we analyze non-player character Claudette Perrick in The Elders Scroll IV:

Business, Technological, and Social Dimensions of Computer Games Edited By: Maria Cruz-Cunha (Ed.) Vitor Hugo Varvalho (Ed.) Paula Tavares (Ed.). IGI, 2011

We address the problem of creating human-like, believable behavior for game characters. To achieve character believability in games, the game designer needs to develop that character so that it fulfills as many aspects of believability as possible. With believable behavior we mean that the game is consistently structured in terms of narration or gameplay so that it is possible to build and maintain coherent relations between the actions of the characters. In this paper, we first analyze the general patterns for game characters ...