EG 2025 - Full Papers - CGF 44-Issue 2

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https://diglib.eg.org/handle/10.2312/3607136

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Browsing EG 2025 - Full Papers - CGF 44-Issue 2 by Subject "Animation"

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    CEDRL: Simulating Diverse Crowds with Example-Driven Deep Reinforcement Learning
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Panayiotou, Andreas; Aristidou, Andreas; Charalambous, Panayiotis; Bousseau, Adrien; Day, Angela
    The level of realism in virtual crowds is strongly affected by the presence of diverse crowd behaviors. In real life, we can observe various scenarios, ranging from pedestrians moving on a shopping street, people talking in static groups, or wandering around in a public park. Most of the existing systems optimize for specific behaviors such as goal-seeking and collision avoidance, neglecting to consider other complex behaviors that are usually challenging to capture or define. Departing from the conventional use of Supervised Learning, which requires vast amounts of labeled data and often lacks controllability, we introduce Crowds using Example-driven Deep Reinforcement Learning (CEDRL), a framework that simultaneously leverages multiple crowd datasets to model a broad spectrum of human behaviors. This approach enables agents to adaptively learn and exhibit diverse behaviors, enhancing their ability to generalize decisions across unseen states. The model can be applied to populate novel virtual environments while providing real-time controllability over the agents' behaviors. We achieve this through the design of a reward function aligned with real-world observations and by employing curriculum learning that gradually diminishes the agents' observation space. A complexity characterization metric defines each agent's high-level crowd behavior, linking it to the agent's state and serving as an input to the policy network. Additionally, a parametric reward function, influenced by the type of crowd task, facilitates the learning of a diverse and abstract behavior ''skill'' set. We evaluate our model on both training and unseen real-world data, comparing against other simulators, showing its ability to generalize across scenarios and accurately reflect the observed complexity of behaviors. We also examine our system's controllability by adjusting the complexity weight, discovering that higher values lead to more complex behaviors such as wandering, static interactions, and group dynamics like joining or leaving. Finally, we demonstrate our model's capabilities in novel synthetic scenarios.
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    Cloth Animation with Time-dependent Persistent Wrinkles
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Gong, Deshan; Yang, Yin; Shao, Tianjia; Wang, He; Bousseau, Adrien; Day, Angela
    Persistent wrinkles are often observed on crumpled garments e.g., the wrinkles around the knees after sitting for a while. Such wrinkles can be easily recovered if not deformed for long, and otherwise be persistent. Since they are vital to the visual realism of cloth animation, we aim to simulate realistic looking persistent wrinkles. To this end, we present a physics-inspired finegrained wrinkle model. Different from existing methods, we recognize the importance of the interplay between internal friction and plasticity during wrinkle formation. Furthermore, we model their time dependence for persistent wrinkles. Our model is capable of not only simulating realistic wrinkle patterns, but also their time-dependent changes according to how long the deformation is maintained. Through extensive experiments, we show that our model is effective in simulating realistic spatial and temporal varying wrinkles, versatile in simulating different materials, and capable of generating more fine-grained wrinkles than the state of the art.
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    DragPoser: Motion Reconstruction from Variable Sparse Tracking Signals via Latent Space Optimization
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Ponton, Jose Luis; Pujol, Eduard; Aristidou, Andreas; Andujar, Carlos; Pelechano, Nuria; Bousseau, Adrien; Day, Angela
    High-quality motion reconstruction that follows the user's movements can be achieved by high-end mocap systems with many sensors. However, obtaining such animation quality with fewer input devices is gaining popularity as it brings mocap closer to the general public. The main challenges include the loss of end-effector accuracy in learning-based approaches, or the lack of naturalness and smoothness in IK-based solutions. In addition, such systems are often finely tuned to a specific number of trackers and are highly sensitive to missing data, e.g., in scenarios where a sensor is occluded or malfunctions. In response to these challenges, we introduce DragPoser, a novel deep-learning-based motion reconstruction system that accurately represents hard and dynamic constraints, attaining real-time high end-effectors position accuracy. This is achieved through a pose optimization process within a structured latent space. Our system requires only one-time training on a large human motion dataset, and then constraints can be dynamically defined as losses, while the pose is iteratively refined by computing the gradients of these losses within the latent space. To further enhance our approach, we incorporate a Temporal Predictor network, which employs a Transformer architecture to directly encode temporality within the latent space. This network ensures the pose optimization is confined to the manifold of valid poses and also leverages past pose data to predict temporally coherent poses. Results demonstrate that DragPoser surpasses both IK-based and the latest data-driven methods in achieving precise end-effector positioning, while it produces natural poses and temporally coherent motion. In addition, our system showcases robustness against on-the-fly constraint modifications, and exhibits adaptability to various input configurations and changes. The complete source code, trained model, animation databases, and supplementary material used in this paper can be found at https://upc-virvig.github.io/DragPoser
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    "Wild West" of Evaluating Speech-Driven 3D Facial Animation Synthesis: A Benchmark Study
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Haque, Kazi Injamamul; Pavlou, Alkiviadis; Yumak, Zerrin; Bousseau, Adrien; Day, Angela
    Recent advancements in the field of audio-driven 3D facial animation have accelerated rapidly, with numerous papers being published in a short span of time. This surge in research has garnered significant attention from both academia and industry with its potential applications on digital humans. Various approaches, both deterministic and non-deterministic, have been explored based on foundational advancements in deep learning algorithms. However, there remains no consensus among researchers on standardized methods for evaluating these techniques. Additionally, rather than converging on a common set of datasets and objective metrics suited for specific methods, recent works exhibit considerable variation in experimental setups. This inconsistency complicates the research landscape, making it difficult to establish a streamlined evaluation process and rendering many cross-paper comparisons challenging. Moreover, the common practice of A/B testing in perceptual studies focus only on two common metrics and not sufficient for non-deterministic and emotion-enabled approaches. The lack of correlations between subjective and objective metrics points out that there is a need for critical analysis in this space. In this study, we address these issues by benchmarking state-of-the-art deterministic and non-deterministic models, utilizing a consistent experimental setup across a carefully curated set of objective metrics and datasets. We also conduct a perceptual user study to assess whether subjective perceptual metrics align with the objective metrics. Our findings indicate that model rankings do not necessarily generalize across datasets, and subjective metric ratings are not always consistent with their corresponding objective metrics. The supplementary video, edited code scripts for training on different datasets and documentation related to this benchmark study are made publicly available- https://galib360.github.io/face-benchmark-project/.