Normoyle, Aline

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2012 - 20159
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Now showing 1 - 9 of 9
  • Publication
    The Effect of Posture and Dynamics on the Perception of Emotion
    (2013-01-01) Normoyle, Aline; Liu, Fannie; Badler, Norman I; Kapadia, Mubbasir; Jorg, Sophie
    Motion capture remains a popular and widely-used method for animating virtual characters. However, all practical applications of motion capture rely on motion editing techniques to increase the reusability and flexibility of captured motions. Because humans are proficient in detecting and interpreting subtle details in human motion, understanding the perceptual consequences of motion editing is essential. Thus in this work, we perform three experiments to gain a better understanding of how motion editing might affect the emotional content of a captured performance, particularly changes in posture and dynamics, two factors shown to be important perceptual indicators of bodily emotions. In these studies, we analyse the properties (angles and velocities) and perception (recognition rates and perceived intensities) of a varied set of full-body motion clips representing the six emotions anger, disgust, fear, happiness, sadness, and surprise. We have found that emotions are mostly conveyed through the upper body, that the perceived intensity of an emotion can be reduced by blending with a neutral motion, and that posture changes can alter the perceived emotion but subtle changes in dynamics only alter the intensity.
  • Publication
    Experimental Analysis of Motion Style
    (2015-01-01) Normoyle, Aline
    For interactive 3D applications and games, the ability to edit, combine, and adapt motion capture is an important technique for reducing labor, project complexity, and storage overhead. Stylistic motion capture, in particular, has unique challenges since editing can alter the original intent of the actor -- sometimes with poor consequences as viewers can pick up subtle differences in body language. Thus, this thesis aims to enhance motion capture techniques, particularly when it is important that the stylistic intent of a motion is not unintentionally altered, when we might need to quantify the stylistic nature of the motion, and when better tools can help naive users works with large stylistic motion sets. In our first experiments, we investigate how changes introduced by motion editing might alter the emotional content of a motion. We find that emotions were mostly conveyed through the upper body, that the perceived intensity of an emotion can be reduced by blending with a neutral motion, and that posture changes can alter the perceived emotion but subtle changes in dynamics only alter the intensity. In our next experiments, we investigate whether fundamental numerical differences exist between neutral and stylistic motions of a single motion category and find that neutral walks had significantly lower torques than stylistic motions. Next, we model the variation over our stylistic walks using PCA by decoupling each walking example motion into an average and stylistic part such that only the stylistic part is transformed to PCA space. Although our use of PCA for motion modeling is not novel, our decision to decouple motions is a simple enhancement that makes the use of the PCA model produce consistently good output for blending, clustering, searching, and browsing. In our final experiments, we investigate whether using a minimap, created from our PCA model, to browse stylistic motions helps non-expert users search and edit styles. We find that 82\% of participants prefer the map to a label-based interface and that when not under time pressure, users performed equally well with the map, although using fewer mouse clicks and producing more varied results.
  • Publication
    Trade-Offs Between Responsiveness and Naturalness for Player Characters
    (2014-01-01) Normoyle, Aline; Jörg, Sophie
    Real-time animation controllers are fundamental for animating characters in response to player input. However, the design of such controllers requires making trade-offs between the naturalness of the character’s motions and the promptness of the character’s response. In this paper, we investigate the effects of such tradeoffs on the players’ enjoyment, control, satisfaction, and opinion of the character in a simple platform game. In our first experiment, we compare three controllers having the same responsiveness, but varying levels of naturalness. In the second experiment, we compare three controllers having increasing realism but at the expense of decreased responsiveness. Not surprisingly, our least responsive controller negatively affects players’ performance and perceived ability to control the character. However, we also find that players are most satisfied with their own performance using our least natural controller, in which the character moves around the environment in a static pose; that differences in animation can significantly alter players’ enjoyment with responsiveness being equal; and that players do not report increased motion quality with our most natural controller, despite viewers outside of a game context rating the same controller as significantly more natural than our other conditions.
  • Publication
    Player Perception of Delays and Jitter in Character Responsiveness
    (2014-01-01) Normoyle, Aline; Guerrero, Gina; Jörg, Sophie
    Response lag in digital games is known to negatively affect a player’s game experience. Particularly with networked multiplayer games, where lag is typically unavoidable, the impact of delays needs to be well understood so that its effects can be mitigated. In this paper, we investigate two aspects of lag independently: latency (constant delay) and jitter (varying delay). We evaluate how latency and jitter each affect a player’s enjoyment, frustration, performance, and experience as well as the extent to which players can adjust to such delays after a few minutes of gameplay. We focus on a platform game where the player controls a virtual character through a world. We find that delays up to 300ms do not impact the players’ experience as long as they are constant. When jitter was added to a delay of 200ms, however, the lag was noticed by participants more often, hindered players’ ability to improve with practice, increased how often they failed to reach the goal of the game, and reduced the perceived motion quality of the character.
  • Publication
    Stochastic Activity Authoring With Direct User Control
    (2014-01-01) Normoyle, Aline; Safonova, Alla; Likhachev, Maxim
    Crowd activities are often randomized to create the appearance of heterogeneity. However, the parameters that control randomization are frequently hard to tune because it is unclear how changes at the character level affect the high-level appearance of the crowd. We propose a method for computing randomization parameters that supports direct animator control. Given details about the environment, available activities, timing information and the desired highlevel appearance of the crowd, we model the problem as a graph, formulate a convex optimization problem, and solve for a set of stochastic transition rates which satisfy the constraints. Unlike the use of heuristics for adding randomness to crowd activities, our approach provides guarantees on convergence to the desired result, allows for decentralized simulation, and supports a variety of constraints. In addition, because the rates can be pre-computed, no additional runtime processing is needed during simulation.
  • Publication
    How Responsiveness Affects Players' Perception in Digital Games
    (2012-01-01) Normoyle, Aline; Jorg, Sophie; Safonova, Alla
    Digital games with realistic virtual characters have become very popular. The ability for players to promptly control their character is a crucial feature of these types of games, be it platform games, first-person shooters, or role-playing games. Controller latencies, meaning delays in the responsiveness of a player’s character, for example due to extensive computations or to network latencies, can considerably reduce the player’s enjoyment of a game. In this paper, we present a thorough analysis of the consequences of such delays on the player’s experience across three parts of a game with different levels of difficulty. We investigate the effects of responsiveness on the player’s enjoyment, performance, and perception of the game, as well as the player’s adaptability to delays. We find that responsiveness is very important for the player as delays affect the player’s enjoyment of the game as well as the player’s performance. A quick responsiveness becomes essential for more challenging tasks.
  • Publication
    Egress Online: Towards Leveraging Massively, Multiplayer Environments for Evacuation Studies
    (2012-01-01) Normoyle, Aline; Drake, John; Safonova, Alla
    Large datasets of real human behaviors are of huge benefit across numerous domains, including evacuation safety, urban planning, marketing, and ergonomics. However, because large-scale experiments involving real human subjects are expensive and prohibitively difficult to organize, such datasets are scarce. Thus in this paper, we propose the use of massively multiplayer online (MMO) communities as an inexpensive and innovative way to capture datasets of large numbers of people under different conditions. We describe our implementation of an online data collection system, based on games, inside the popular massively multiplayer, online environment of Second Life. We evaluate the use of this system for performing evacuation experiments using a mix of Second Life residents and players recruited on campus. Our system was able to draw online participants, support data collection needs, and provide potential insights into high-level evacuation behaviors such as the choices of exit, effects of building debris, and the use-patterns of a building. Through experiments performed using our system, we found that Second Life residents found the game controls and environment to be significantly more compelling than lab participants; that players unfamiliar with our office building tended to evacuate primarily via the front entrance; and that in-game debris significantly increased the numbers of participants who failed to exit a building safely.
  • Publication
    Evaluating Perceived Trust From Procedurally Animated Gaze
    (2013-01-01) Normoyle, Aline; Badler, Jeremy B.; Badler, Norman I; Fan, Teresa; Cassol, Vinicius J.; Musse, Soraia R.
    Adventure role playing games (RPGs) provide players with increasingly expansive worlds, compelling storylines, and meaningful fictional character interactions. Despite the fast-growing richness of these worlds, the majority of interactions between the player and non-player characters (NPCs) still remain scripted. In this paper we propose using an NPC’s animations to reflect how they feel towards the player and as a proof of concept, investigate the potential for a straightforward gaze model to convey trust. Through two perceptual experiments, we find that viewers can distinguish between high and low trust animations, that viewers associate the gaze differences specifically with trust and not with an unrelated attitude (aggression), and that the effect can hold for different facial expressions and scene contexts, even when viewed by participants for a short (five second) clip length. With an additional experiment, we explore the extent that trust is uniquely conveyed over other attitudes associated with gaze, such as interest, unfriendliness, and admiration.
  • Publication
    Game-Based Data Capture for Player Metrics
    (2012-10-01) Normoyle, Aline; Drake, John; Safonova, Alla; Likhachev, Maxim
    Player metrics are an invaluable resource for game designers and QA analysts who wish to understand players, monitor and improve game play, and test design hypotheses. Usually such metrics are collected in a straightforward manner by passively recording players; however, such an approach has several potential drawbacks. First, passive recording might fail to record metrics which correspond to an infrequent player behavior. Secondly, passive recording can be a costly, laborious, and memory intensive process, even with the aid of tools. In this paper, we explore the potential for an active approach to player metric collection which strives to collect data more efficiently, and thus with less cost. We use an online, iterative approach which models the relationship between player metrics and in-game situations probabilistically using a Markov Decision Process (MDP) and solves it for the best game configurations to run. To analyze the benefits and limitations of this approach, we implemented a system, called GAMELAB, for recording player metrics in Second Life.