Cassidy Curtis
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Toward Believable Acting for Autonomous Animated Characters
Sigurdur Orn Adalgeirsson
Horia Stefan Ciurdar
Peter F Mcdermott
JD Velásquez
W. Bradley Knox
Alonso Martinez
Dei Gaztelumendi
Norberto Adrian Goussies
Tianyu Liu
Palash Nandy
Proceedings of the 15th ACM SIGGRAPH Conference on Motion, Interaction and Games (MIG '22), New York, NY, USA (2022), pp. 1-15
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This paper describes design principles and a system, based on reinforcement learning and procedural animation, to create an autonomous character capable of believable acting—exhibiting a responsive and expressive illusion of interactive life, grounded in its subjective experience of its world. The design principles incorporate knowledge from animation, human-computer interaction, and psychology, articulating guidelines that, when followed, support a viewer’s suspension of disbelief. The system’s reinforcement learning brain generates action, emotion, and attention signals based on motivational drives, and its procedural animation system translates those signals into expressive biophysical movement in real time. We demonstrate the system on a stylized quadruped character in a virtual habitat. In a user study, participants rated the character favorably on animacy and ability to experience emotions, which is consistent with finding the character believable.
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We present Fluidymation---a new example-based approach to stylizing animation that employs the natural dynamics of artistic media to convey a prescribed motion. In contrast to previous stylization techniques that transfer the hand-painted appearance of a static style exemplar and then try to enforce temporal coherence, we use moving exemplars that capture the artistic medium's inherent dynamic properties, and transfer both movement and appearance to reproduce natural-looking transitions between individual animation frames. Our approach can synthetically generate stylized sequences that look as if actual paint is diffusing across a canvas in the direction and speed of the target motion.
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Monster Mash: A Single-View Approach to Casual 3D Modeling and Animation
Marek Dvoroznak
Olga Sorkine-Hornung
ACM Transactions on Graphics (TOG), ACM, New York, NY, USA (2020), pp. 1-12 (to appear)
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We present a new framework for sketch-based modeling and animation of 3D organic shapes that can work entirely in an intuitive 2D domain, enabling a playful, casual experience. Unlike previous sketch-based tools, our approach does not require a tedious part-based multi-view workflow with the explicit specification of an animation rig. Instead, we combine 3D inflation with a novel rigidity-preserving, layered deformation model, ARAP-L, to produce a smooth 3D mesh that is immediately ready for animation. Moreover, the resulting model can be animated from a single viewpoint — and without the need to handle unwanted inter-penetrations, as required by previous approaches. We demonstrate the benefit of our approach on a variety of examples produced by inexperienced users as well as professional animators. For less experienced users, our single-view approach offers a simpler modeling and animating experience than working in a 3D environment, while for professionals, it offers a quick and casual workspace for ideation.
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Immersive media such as virtual and augmented reality pose some interesting new challenges for non-photorealistic animation: we must not only balance the screen-space rules of a 2D visual style against 3D motion coherence, but also account for stereo spatialization and interactive camera movement, at a rate of 90 frames per second. We introduce two new real-time rendering techniques: MetaTexture, an example-based texturing method that adheres to the movement of 3D geometry while preserving the texture’s screen-space characteristics, and Edge Breakup, a method for roughening edges by warping with structured noise. We also describe a custom rendering pipeline featuring art-directable coloring, shadow filtering, and texture indication, and our approach to animating and rendering a painterly ocean in real time. We show how we have used these techniques to achieve the “moving illustration” style of the real-time immersive short film “Age of Sail”.
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Non-Photorealistic Animation for Immersive Storytelling
Kevin Dart
Theresa Latzko
John Kahrs
The Eurographics Association, Genoa, Italy (2019), pp. 1-10
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Immersive media such as virtual and augmented reality pose some interesting new challenges for non-photorealistic animation: we must not only balance the screen-space rules of a 2D visual style against 3D motion coherence, but also account for stereo spatialization and interactive camera movement, at a rate of 90 frames per second. We introduce two new real-time rendering techniques: MetaTexture, an example-based multiresolution texturing method that adheres to the movement of 3D geometry while maintaining a consistent level of screen-space detail, and Edge Breakup, a method for roughening edges by warping with structured noise. We show how we have used these techniques, along with art-directable coloring, shadow filtering, and shader-based texture indication, to achieve the “moving illustration” style of the immersive short film "Age of Sail".
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