EG2024

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The Use of Photogrammetry in Historic Preservation Curriculum: A Comparative Case Study
(The Eurographics Association, 2024) Kepczynska-Walczak, Anetta; Walczak, Bartosz M.; Zarzycki, Andrzej; Sousa Santos, Beatriz; Anderson, Eike
Computer graphic techniques have emerged as a key player in digital heritage preservation and its dissemination. Photogrammetry allows for high-fidelity captures and virtual reconstructions of the built environment that can be further ported into virtual reality (VR) and augmented reality (AR) experiences. This paper provides a comparative analysis of historic details and building documentation methods in heritage preservation in the context of architectural education. Specifically, it compares two educational case studies conducted in 10-year intervals documenting the same set of historic artifacts with corresponding state-of-the-art digital technologies. The methodology for this paper is a qualitative comparative analysis of two surveying projects that utilized distinct emerging digital technology while sharing the same study subjects and similar tool-driven curricular framework. The research also incorporates a student survey, offering perspectives on teaching strategies and outcomes within this dynamic educational context. The outcomes demonstrate that the technological (tool-driven) shift impacts the way students interact with the investigated artifacts and the changing role of the interpretative versus analytical skills needed to delineate the work. It also changes what are considered primary and secondary knowledge sources.
Real-time Seamless Object Space Shading
(The Eurographics Association, 2024) Li, Tianyu; Guo, Xiaoxin; Hu, Ruizhen; Charalambous, Panayiotis
Object space shading remains a challenging problem in real-time rendering due to runtime overhead and object parameterization limitations. While the recently developed algorithm by Baker et al. [BJ22] enables high-performance real-time object space shading, it still suffers from seam artifacts. In this paper, we introduce an innovative object space shading system leveraging a virtualized per-halfedge texturing schema to obviate excessive shading and preclude texture seam artifacts. Moreover, we implement ReSTIR GI on our system (see Figure 1), removing the necessity of temporally reprojecting shading samples and improving the convergence of areas of disocclusion. Our system yields superior results in terms of both efficiency and visual fidelity.
DeepIron: Predicting Unwarped Garment Texture from a Single Image
(The Eurographics Association, 2024) Kwon, Hyun-Song; Lee, Sung-Hee; Hu, Ruizhen; Charalambous, Panayiotis
Realistic reconstruction of 3D clothing from an image has wide applications, such as avatar creation and virtual try-on. This paper presents a novel framework that reconstructs the texture map for 3D garments from a single garment image with pose. Since 3D garments are effectively modeled by stitching 2D garment sewing patterns, our specific goal is to generate a texture image for the sewing patterns. A key component of our framework, the Texture Unwarper, infers the original texture image from the input garment image, which exhibits warping and occlusion of the garment due to the user's body shape and pose. This is effectively achieved by translating between the input and output images by mapping the latent spaces of the two images. By inferring the unwarped original texture of the input garment, our method helps reconstruct 3D garment models that can show high-quality texture images realistically deformed for new poses. We validate the effectiveness of our approach through a comparison with other methods and ablation studies.
Predictive Modeling of Material Appearance: From the Drawing Board to Interdisciplinary Applications
(The Eurographics Association, 2024) Baranoski, Gladimir V. G.; Mania, Katerina; Artusi, Alessandro
This tutorial addresses one of the fundamental and timely topics of computer graphics research, namely the predictive modeling of material appearance. Although this topic is deeply rooted in traditional areas like rendering and natural phenomena simulation, this tutorial is not limited to cover contents connected to these areas. It also closely looks into the scientific methodology employed in the development of predictive models of light and matter interactions. Given the widespread use of this methodology to find modeling solutions for problems within and outside computer graphics, its discussion from a ''behind the scenes'' perspective aims to underscore practical and far-reaching aspects of interdisciplinary research that are often overlooked in related publications. More specifically, this tutorial unveils constraints and pitfalls found in each of the key stages of the model development process, namely data collection, design and evaluation, and brings forward alternatives to tackle them effectively. Furthermore, besides being a central component of realistic image synthesis frameworks, predictive material appearance models have a scope of applications that can be extended far beyond the generation of believable images. For instance, they can be employed to accelerate the hypothesis generation and validation cycles of research across a wide range of fields, from biology and medicine to photonics and remote sensing, among others. These models can also be used to generate comprehensive in silico (computational) datasets to support the translation of knowledge advances in those fields to real-world applications (e.g., the noninvasive screening of medical conditions and the remote detection of environmental hazards). In fact, a number of them are already being used in physical and life sciences, notably to support investigations seeking to strengthen the current understanding about material appearance changes prompted by mechanisms which cannot be fully studied using standard ''wet'' experimental procedures. Accordingly, such interdisciplinary research initiatives are also discussed in this tutorial through selected case studies involving the use of predictive material appearance models to elucidate challenging scientific questions.
Dense 3D Gaussian Splatting Initialization for Sparse Image Data
(The Eurographics Association, 2024) Seibt, Simon; Chang, Thomas Vincent Siu-Lung; von Rymon Lipinski, Bartosz ; Latoschik, Marc Erich; Liu, Lingjie; Averkiou, Melinos
This paper presents advancements in novel-view synthesis with 3D Gaussian Splatting (3DGS) using a dense and accurate SfM point cloud initialization approach. We address the challenge of achieving photorealistic renderings from sparse image data, where basic 3DGS training may result in suboptimal convergence, thus leading to visual artifacts. The proposed method enhances precision and density of initially reconstructed point clouds by refining 3D positions and extrapolating additional points, even for difficult image regions, e.g. with repeating patterns and suboptimal visual coverage. Our contributions focus on improving ''Dense Feature Matching for Structure-from-Motion'' (DFM4SfM) based on a homographic decomposition of the image space to support 3DGS training: First, a grid-based feature detection method is introduced for DFM4SfM to ensure a welldistributed 3D Gaussian initialization uniformly over all depth planes. Second, the SfM feature matching is complemented by a geometric plausibility check, priming the homography estimation and thereby improving the initial placement of 3D Gaussians. Experimental results on the NeRF-LLFF dataset demonstrate that this approach achieves superior qualitative and quantitative results, even for fewer views, and the potential for a significantly accelerated 3DGS training with faster convergence.
Tackling Diverse Student Backgrounds and Goals while Teaching an Introductory Visual Computing Course at M.Sc. Level
(The Eurographics Association, 2024) Silva, Samuel; Sousa Santos, Beatriz; Anderson, Eike
Visual Computing entails a set of competences that are core for those pursuing Digital Game Development and has become a much sought competence for professionals in a wide variety of fields. In the particular case presented here, the course serves a diverse audience from Multimedia and Design students without previous knowledge in the field and low programming competences, to students that have a previous BS.c in Game Development and have already covered the basic concepts in a previous course. Additionally, the course is also offered as an elective for Computer Science M.Sc. students. This diverse set of background competences and goals motivated designing an approach to the course where each student can build on previous knowledge and have a say on its personal learning path. This article shares the overall approach, presents and discusses the outcomes, and reflects on future evolutions.
EUROGRAPHICS 2024: Tutorials Frontmatter
(Eurographics Association, 2024) Mania, Katerina; Artusi, Alessandro; Mania, Katerina; Artusi, Alessandro
Fast Dynamic Facial Wrinkles
(The Eurographics Association, 2024) Weiss, Sebastian; Chandran, Prashanth; Zoss, Gaspard; Bradley, Derek; Hu, Ruizhen; Charalambous, Panayiotis
We present a new method to animate the dynamic motion of skin micro wrinkles under facial expression deformation. Since wrinkles are formed as a reservoir of skin for stretching, our model only deforms wrinkles that are perpendicular to the stress axis. Specifically, those wrinkles become wider and shallower when stretched, and deeper and narrower when compressed. In contrast to previous methods that attempted to modify the neutral wrinkle displacement map, our approach is to modify the way wrinkles are constructed in the displacement map. To this end, we build upon a previous synthetic wrinkle generator that allows us to control the width and depth of individual wrinkles when generated on a per-frame basis. Furthermore, since constructing a displacement map per frame of animation is costly, we present a fast approximation approach using pre-computed displacement maps of wrinkles binned by stretch direction, which can be blended interactively in a shader. We compare both our high quality and fast methods with previous techniques for wrinkle animation and demonstrate that our work retains more realistic details.
From Few to Full: High-Resolution 3D Object Reconstruction from Sparse Views and Unknown Poses
(The Eurographics Association, 2024) Yao, Grekou; Mavromatis, Sebastien; Mari, Jean-Luc; Liu, Lingjie; Averkiou, Melinos
Recent progress in 3D reconstruction has been driven by generative models, moving from traditional multi-view dependence to single-image diffusion model based techniques. However, these innovative approaches often face challenges with sparse view scenarios, requiring known poses or template shapes, often failing in high-resolution reconstructions. Addressing these issues, we introduce the ''F2F'' (Few to Full) framework, designed for crafting high-resolution 3D models from few views and unknown camera poses, creating fully realistic 3D objects without external constraints. F2F employs a hybrid approach, optimizing both implicit and explicit representations through a unique pipeline involving a pretrained diffusion model for pose estimation, a deformable tetrahedra grid for feature volume construction, and an MLP (neural network) for surface optimization. Our method sets a new standard by ensuring surface geometry, topology, and semantic consistency through differentiable rendering, aiming for a comprehensive solution in 3D reconstruction from sparse views.
Interactive VPL-based Global Illumination on the GPU Using Adaptive Fuzzy Clustering
(The Eurographics Association, 2024) Colom, Arnau; Marques, Ricardo; Santos, Luís Paulo; Liu, Lingjie; Averkiou, Melinos
Physically-based synthesis of high quality imagery results in a significant workload, which makes interactive rendering a very challenging task. Our approach to achieve such interactive frame rates while accurately simulating global illumination phenomena entails developing a Virtual Point Lights (VPL) ray tracer that runs entirely in the GPU. Our performance guarantees arise from clustering both shading points and VPLs and computing visibility only among clusters' representatives. Previous approaches to the same problem resort to K-means clustering, which requires the user to specify the number of clusters; a rather unintuitive requirement. We propose an innovative massively parallel, GPU-efficient, Quality-Threshold clustering algorithm, which requires the user to specify a quality parameter. The algorithm dynamically adjusts the number of clusters depending both on the specified quality threshold and on camera-geometry conditions during execution.
Utilizing Motion Matching with Deep Reinforcement Learning for Target Location Tasks
(The Eurographics Association, 2024) Lee, Jeongmin; Kwon, Taesoo; Shin, Hyunju; Lee, Yoonsang; Hu, Ruizhen; Charalambous, Panayiotis
We present an approach using deep reinforcement learning (DRL) to directly generate motion matching queries for longterm tasks, particularly targeting the reaching of specific locations. By integrating motion matching and DRL, our method demonstrates the rapid learning of policies for target location tasks within minutes on a standard desktop, employing a simple reward design. Additionally, we propose a unique hit reward and obstacle curriculum scheme to enhance policy learning in environments with moving obstacles.
Bridging the Distance in Education: Design and Implementation of a Synchronous, Browser-Based VR Remote Teaching Tool
(The Eurographics Association, 2024) Pehlic, Abdulmelik; Augsdörfer, Ursula; Sousa Santos, Beatriz; Anderson, Eike
The rapid shift to remote education has presented numerous challenges for educators and students alike. Virtual Reality (VR) has emerged as a promising solution, offering immersive and interactive learning experiences. We design and implement a synchronous, browser-based VR teaching tool. The tool is compatible with budget VR equipment and enables meaningful engagement between teachers and students in a virtual setting, as well as active participation and interaction across a range of platforms, thus solving a range of disadvantages of current approaches.
A Survey on Realistic Virtual Human Animations: Definitions, Features and Evaluations
(The Eurographics Association and John Wiley & Sons Ltd., 2024) Rekik, Rim; Wuhrer, Stefanie; Hoyet, Ludovic; Zibrek, Katja; Olivier, Anne-Hélène; Aristidou, Andreas; Macdonnell, Rachel
Generating realistic animated virtual humans is a problem that has been extensively studied with many applications in different types of virtual environments. However, the creation process of such realistic animations is challenging, especially because of the number and variety of influencing factors, that should then be identified and evaluated. In this paper, we attempt to provide a clearer understanding of how the multiple factors that have been studied in the literature impact the level of realism of animated virtual humans, by providing a survey of studies assessing their realism. This includes a review of features that have been manipulated to increase the realism of virtual humans, as well as evaluation approaches that have been developed. As the challenges of evaluating animated virtual humans in a way that agrees with human perception are still active research problems, this survey further identifies important open problems and directions for future research.
A Research Methodology Course in a Game Development Curriculum
(The Eurographics Association, 2024) Hu, Yan; Sundstedt, Veronica; Goswami, Prashant; Sousa Santos, Beatriz; Anderson, Eike
Research methodology courses can often be considered part of a computer science curriculum. These basic or advanced-level courses are taught in terms of traditional research methods. This paper presents and discusses a research methodology course curriculum for students studying programs focusing on digital game development (more specifically, focusing on game engineering). Our research methodology course prepares students for their upcoming thesis by encouraging a research-oriented approach. This is done by exploring new research areas in game engineering as a basis for research analysis and by applying research methods practically in a smaller project. This paper presents the course structure, assignments, and lessons learned. Together with existing literature, it demonstrates important aspects to consider in teaching and learning game research methodologies. The course evaluation found that the students appreciated the interactive lectures, close staff supervision, and detailed feedback on the scientific writing process.
FACTS: Facial Animation Creation using the Transfer of Styles
(The Eurographics Association, 2024) Saunders, Jack R.; Namboodiri, Vinay P.; Hu, Ruizhen; Charalambous, Panayiotis
The ability to accurately capture and express emotions is a critical aspect of creating believable characters in video games and other forms of entertainment. Traditionally, this animation has been achieved with artistic effort or performance capture, both requiring costs in time and labor. More recently, audio-driven models have seen success, however, these often lack expressiveness in areas not correlated to the audio signal. In this paper, we present a novel approach to facial animation by taking existing animations and allowing for the modification of style characteristics. We maintain the lip-sync of the animations with this method thanks to the use of a novel viseme-preserving loss. We perform quantitative and qualitative experiments to demonstrate the effectiveness of our work.
Teaching Game Programming in an Upper-level Computing Course Through the Development of a C++ Framework and Middleware
(The Eurographics Association, 2024) Hooper, Steffan; Wünsche, Burkhard C.; Denny, Paul; Luxton-Reilly, Andrew; Sousa Santos, Beatriz; Anderson, Eike
The game development industry has a programming skills shortage, with industry surveys often ranking game programming as the top skill-in-demand across small, mid-sized, and large triple-A (AAA) game studios. C++ programming skills are desired, however, educators can perceive C++ as too difficult to teach due to its size and complexity. We address the challenges of teaching C++ in an upper-level Game Programming course and demonstrate how learners are up-skilled in C++ game programming, providing insights and reflections on the course. We show how through careful educational-design choices, combined with scaffolding a C++ framework and contemporary middleware, it is possible to transition learners to C++ for game programming.
StarDEM: Efficient Discrete Element Method for Star-shaped Particles
(The Eurographics Association, 2024) Schreck, Camille; Lefebvre, Sylvain; Jourdan, David; Martínez, Jonàs; Hu, Ruizhen; Charalambous, Panayiotis
Granular materials composed of particles with complex shapes are challenging to simulate due to the high number of collisions between the particles. In this context, star shapes are promising: they cover a wide range of geometries from convex to concave and have interesting geometric properties. We propose an efficient method to simulate a large number of identical star-shaped particles. Our method relies on an effective approximation of the contacts between particles that can handle complex shapes, including highly non-convex ones. We demonstrate our method by implementing it in a 2D simulation using the Discrete Element Method, both on the CPU and GPU.
Can GPT-4 Trace Rays
(The Eurographics Association, 2024) Feng, Tony Haoran; Wünsche, Burkhard C.; Denny, Paul; Luxton-Reilly, Andrew; Hooper, Steffan; Sousa Santos, Beatriz; Anderson, Eike
Ray Tracing is a fundamental concept often taught in introductory Computer Graphics courses, and Ray-Object Intersection questions are frequently used as practice for students, as they leverage various skills essential to learning Ray Tracing or Computer Graphics in general, such as geometry and spatial reasoning. Although these questions are useful in teaching practices, they may take some time and effort to produce, as the production procedure can be quite complex and requires careful verification and review. From the recent advancements in Artificial Intelligence, the possibility of automated or assisted exercise generation has emerged. Such applications are unexplored in Ray Tracing education, and if such applications are viable in this area, then it may significantly improve the productivity and efficiency of Computer Graphics instructors. Additionally, Ray Tracing is quite different to the mostly text-based tasks that LLMs have been observed to perform well on, hence it is unclear whether they can cope with these added complexities of Ray Tracing questions, such as visual processing and 3D geometry. Hence we ran some experiments to evaluate the usefulness of leveraging GPT-4 for assistance when creating exercises related to Ray Tracing, more specifically Ray-Object Intersection questions, and we found that an impressive 67% of its generated questions can be used in assessments verbatim, but only 42% of generated model solutions were correct.
Virtual Instrument Performances (VIP): A Comprehensive Review
(The Eurographics Association and John Wiley & Sons Ltd., 2024) Kyriakou, Theodoros; Alvarez de la Campa Crespo, Merce; Panayiotou, Andreas; Chrysanthou, Yiorgos; Charalambous, Panayiotis; Aristidou, Andreas; Aristidou, Andreas; Macdonnell, Rachel
Driven by recent advancements in Extended Reality (XR), the hype around the Metaverse, and real-time computer graphics, the transformation of the performing arts, particularly in digitizing and visualizing musical experiences, is an ever-evolving landscape. This transformation offers significant potential in promoting inclusivity, fostering creativity, and enabling live performances in diverse settings. However, despite its immense potential, the field of Virtual Instrument Performances (VIP) has remained relatively unexplored due to numerous challenges. These challenges arise from the complex and multi-modal nature of musical instrument performances, the need for high precision motion capture under occlusions including the intricate interactions between a musician's body and fingers with instruments, the precise synchronization and seamless integration of various sensory modalities, accommodating variations in musicians' playing styles, facial expressions, and addressing instrumentspecific nuances. This comprehensive survey delves into the intersection of technology, innovation, and artistic expression in the domain of virtual instrument performances. It explores musical performance multi-modal databases and investigates a wide range of data acquisition methods, encompassing diverse motion capture techniques, facial expression recording, and various approaches for capturing audio and MIDI data (Musical Instrument Digital Interface). The survey also explores Music Information Retrieval (MIR) tasks, with a particular emphasis on the Musical Performance Analysis (MPA) field, and offers an overview of various works in the realm of Musical Instrument Performance Synthesis (MIPS), encompassing recent advancements in generative models. The ultimate aim of this survey is to unveil the technological limitations, initiate a dialogue about the current challenges, and propose promising avenues for future research at the intersection of technology and the arts.
Next Generation 3D Face Models
(The Eurographics Association, 2024) Chandran, Prashanth; Yang, Lingchen; Mania, Katerina; Artusi, Alessandro
Having a compact, expressive and artist friendly way to represent and manipulate human faces has been of prime interest to the visual effects community for the past several decades as face models play a very important role in many face capture workflows. In this short course, we go over the evolution of 3D face models used to model and animate facial identity and expression in the computer graphics community, and discuss how the recent emergence of deep face models is transforming this landscape by enabling new artistic choices. In this first installment, the course will take the audience through the evolution of face models, starting with simple blendshape models introduced in the 1980s; that continue to be extremely popular today, to recent deep shape models that utilize neural networks to represent and manipulate face shapes in an artist friendly fashion. As the course is meant to be beginner friendly, the course will commence with a quick introduction to non-neural parametric shape models starting with linear blendshape and morphable models. We will then switch focus to deep shape models, particularly those that offer intuitive control to artists. We will discuss multiple variants of such deep face models that i) allow semantic control, ii) are agnostic to the underlying topology of the manipulated shape, iii) provide the ability to explicitly model a sequence of 3D shapes or animations, and iv) allow for the simulation of physical effects. Applications that will be discussed include face shape synthesis, identity and expression interpolation, rig generation, performance retargeting, animation synthesis and more.

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