ABSTRACT This work proposes a novel approach to transform any modern game engine pipeline, for optimized performance and enhanced user experiences in extended reality (XR) environments decoupling the physics engine from the game engine pipeline and using a client‐server architecture creates a scalable solution, efficiently serving multiple graphics clients on head‐mounted displays (HMDs) with a single physics engine on edge‐cloud infrastructure. This approach ensures better synchronization in multiplayer scenarios without introducing overhead in single‐player experiences, maintaining session continuity despite changes in user participation. Relocating the Physics Engine to an edge or cloud node reduces strain on local hardware, dedicating more resources to high‐quality rendering and unlocking the full potential of untethered HMDs. We present four algorithms that decouple the physics engine, increasing frame rates and Quality of Experience (QoE) in VR simulations, supporting advanced interactions, numerous physics objects, and multiuser sessions with over 100 concurrent users. Incorporating a Geometric Algebra interpolator reduces inter‐calls between dissected parts, maintaining QoE and easing network stress. Experimental validation, with more than 100 concurrent users, 10,000 physics objects, and softbody simulations, confirms the technical viability of the proposed architecture, showcasing transformative capabilities for more immersive and collaborative XR applications without compromising performance.

This special issue is the third issue dedicated to the best papers of the second Call of the CGI 2022 conference. In 2022, CGI (Computer Graphics International) was organized by MIRALab at the University of Geneva. It was supported by the Computer Graphics Society. The conference was very successful and attracted more than 150 online participants through Zoom. Twenty-six papers were selected from more than 100 papers submitted to the second call of the conference. This issue contains the last eight full papers. Nine papers were already published in the 33.5 issue and nine papers in the 33.6 issue. All papers have been reviewed by two or three reviewers of the CGI 2022 Program Committee, revised according to the reviewers' comments, and checked and reviewed again by the CAVW Editorial Board. Data-driven based double-layer bicycle simulation model by Tianlu Mao, Zhong Fang, Qinyuan Yan, and Zhaoqi Wang, from Academy of Sciences, Beijing, and Ruoyu Meng and Shaohua Liu, all in China. This special issue is edited by the program-co-chairs of CGI2022 conference.

This special issue is dedicated to the best papers of the second Call of the CGI 2022 conference. This year CGI (Computer Graphics International) was organized by MIRALab at the University of Geneva. It was supported by the Computer Graphics Society. The conference was very successful and attracted more than 150 online participants through Zoom. Twenty-six papers were selected from more than 100 papers submitted to the second call of the conference. This issue contains nine full papers. The other selected papers will be published in the two next issues respectively 33.6 and 34.1. All papers have been reviewed by two or three reviewers of the CGI 2022 Program Committee, revised according to the reviewers' comments, and checked and reviewed again by the CAVW Editorial Board. The first paper in this issue is the recipient of the CAVW Best Paper Award given at CGI 2022 by the Award Committee chaired by Professor Nadia Magnenat Thalmann, MIRALab-University of Geneva, Switzerland, and Professor Constantine Stephanidis, ICS—FORTH, Greece. This awarded paper is: Simulation of collective pursuit-evasion behavior with runtime situational awareness by Zhenjing Yu, Tan Junyin, and Sheng Li, from Peking University, China.

This special issue is the second issue dedicated to the best papers of the second Call of the CGI 2022 conference. This year CGI (Computer Graphics International) was organized by MIRALab at the University of Geneva. It was supported by the Computer Graphics Society. The conference was very successful and attracted more than 150 online participants through Zoom. Twenty-six papers were selected from more than 100 papers submitted to the second call of the conference. This issue contains nine full papers. Nine papers were already published in the 33.5 issue and the last papers will appear in the issue 34.1. All papers have been reviewed by two or three reviewers of the CGI 2022 Program Committee, revised according to the reviewers' comments, and checked and reviewed again by the CAVW Editorial Board. This special issue is edited by the program co-chairs of CGI2022 conference: Jinman Kim, Sydney University, Australia, George Papagiannakis, University of Crete, Greece, Bin Sheng, Shanghai Jiao Tong University, China, Daniel Thalmann, EPFL, Switzerland.

CGI is one of the oldest international conferences in Computer Graphics in the world.It is the official conference of the Computer Graphics Society (CGS), a long-standing international computer graphics organization.CGI conference has been held annually in many different countries across the world and has gained a reputation as one of the key conferences for researchers and practitioners to share their achievements and discover the latest advances in Computer Graphics.With the change in the form of networking and intelligence in industry, manufacturing and all aspects of society, and the development of technology, we are aware of the increasingly obvious trend of evolution of intelligence in human society.Among them, metaverse is increasingly becoming a hot spot for research in various industries and has broad application prospects.It absorbs the results of the information revolution, the Internet revolution, the artificial intelligence revolution, and the virtual reality technology revolution including VR, AR, MR, and especially game engines, showing mankind the possibility of building a holographic digital world parallel to the traditional physical world.The core of the metaverse lies in the hosting of virtual assets and virtual identities.Unlike traditional games, users can experience different content, make different friends, create their own creations, and perform a series of virtual activities in the metaverse.With the popularity of smart terminals and the rise of applications such as e-commerce/short videos/games, "metaverse" has become an inevitable trend in the development of digital society.In a broad sense, the "metaverse" is a virtual space-time consisting of a series of augmented reality (AR), virtual reality (VR) and the Internet; in a narrow sense, the "metaverse" is a virtual world parallel to the real world.By wearing a helmet and headset device, one can enter a three-dimensional world constructed by computer simulation through a terminal connection".The new mode of "virtual reality" presentation and scene interaction for scene visualization will be more conducive to better visual effects and interactive operations in the digital world.The metaverse becomes the best track and new growth point for AI applications because of its huge imagination, close social attention and rich landing scenes, while AI and related arithmetic, big data and other technical fields are the technical base for the metaverse to become a kind of concrete expression in the future.Overall, with the further development of human technology and the improvement of hardware level, it becomes possible for humans to build a "meta" world.This year, CGI 2022 is still online as the pandemic prevents many researchers to come to Geneva.The conference CGI is organized from September 12 to September 16, 2022, by MIRALab at the Computer Research Centre (CUI) of the University of Geneva, in Switzerland.All presentations are online.In addition to the Visual Computer journal published by Springer, and the CAVW journal (Computer Animation and Virtual Worlds) published by Wiley, we have also included the twenty-three accepted papers in the VRIH journal (Virtual Reality and Intelligent Hardware journal published by Science Press).This special issue is composed of the six papers related to the topic of metaverse from these twenty-three accepted papers.

While the body of research focusing on Intelligent Environments (IEs) programming by adults is steadily growing, informed insights about children as programmers of such environments are limited. Previous work already established that young children can learn programming basics. Yet, there is still a need to investigate whether this capability can be transferred in the context of IEs, since encouraging children to participate in the management of their intelligent surroundings can enhance responsibility, independence, and the spirit of cooperation. We performed a user study (N=15) with children aged 7-12, using a block-based, gamified AR spatial coding prototype allowing to manipulate smart artifacts in an Intelligent Living room. Our results validated that children understand and can indeed program IEs. Based on our findings, we contribute preliminary implications regarding the use of specific technologies and paradigms (e.g. AR, trigger-action programming) to inspire future systems that enable children to create enriching experiences in IEs.

In the next few years, new demanding applications will be supported on mobile platforms by reconciling two conflicting requirements: high performance (often with real-time limitations) and low power consumption. The objective of the vipGPU project is to develop hardware and software technology to provide efficient support for two such application scenarios, namely (a) simultaneous localization and mapping (SLAM) in mobile robotics systems, and (b) virtual reality (VR) in portable devices to simulate serious games with emphasis on simulating surgical interventions and medical training in general. In this project, we aim at developing a new heterogeneous platform consisting of hardware accelerators for low power embedded systems optimized (at the hardware and software level) for the implementation of the two applications mentioned above.

When referring to augmented reality characters, their actual size comparing to their physical surroundings is an important factor responsible for creating more realistic and immersive environments. By creating life-sized augmented characters we are able to present them in real time with real characters and create applications where both real and digital characters co-exist, in 'life-size' dimensions, as opposed to mostly small-scale AR characters. In this work, we have created AR crowd and group simulations with life-sized augmented characters that simulate crowd behavior with real human locomotive motions and body gestures.

The aim of this study is to identify a gene expression signature which is characteristic of ER status in breast cancer patients. To our knowledge, this is the first microarray study in Greece involving clinical samples. We identified 97 genes that are characteristic for ER status and can well distinguish the ER+ from the ER- samples. We shrank our list to a 11-gene list correlating to the same patient ER status. We found a significant overlap of these genes with published ER status characteristic signatures like the ones of West et.al. and of Vanpsilat Veer et. al.. This fact is very important given the minimal overlap of such genes reported by others . In order to obtain a molecular insight into how the expression of estrogen receptor activates cancer cells, we found associations with biological pathways. Interestingly, the vast majority of these genes are highly related to breast cancer.

Abstract In this issue, you will find a special section on Wireless and Mobile Technologies in Mixed Realities, with four papers introduced by the two guest editors Gurminder Singh and Georges Papagiannakis. The last paper of the issue is a regular paper by I. Mansa et al. entitled “Analysis of coherence strategies for stereo occlusion culling.” This paper explores the benefits that can be achieved for stereoscopic visualization when using occlusion‐culling strategies. It shows the limitations placed by compact and not densely occluded scenarios and the gains that can be achieved when rendering stereo images using occlusion culling. The experiments carried out test combinations of occlusion stereo coherence and occlusion frame coherence. The algorithm presented can be easily implemented and provides a significant boost in performances.

Abstract Recent advances in hardware and software for mobile computing have enabled a new breed of mobile augmented reality (AR) systems and applications. A new breed of computing called ‘augmented ubiquitous computing’ has resulted from the convergence of wearable computing, wireless networking, and mobile AR interfaces. In this paper, we provide a survey of different mobile and wireless technologies and how they have impact AR. Our goal is to place them into different categories so that it becomes easier to understand the state of art and to help identify new directions of research. Copyright © 2008 John Wiley & Sons, Ltd.

With the advent of ubiquitous and pervasive computing environments, one of promising applications is a guidance system. In this paper, we propose a mobile mixed reality guide system for indoor environments, [email protected] A mobile computing device (Sony's Ultra Mobile PC) is hidden inside a jacket and a user selects a destination inside a building through voice commands. A 3D virtual assistant then appears in the see-through HMD and guides him/her to destination. Thus, the user simply follows the virtual guide. [email protected] also suggests the most suitable virtual character (e.g. human guide, dog, cat, etc.) based on user preferences and profiles. Depending on user profiles, different security levels and authorizations for content are previewed. Concerning indoor location tracking, WiFi, RFID, and sensor-based methods are integrated in this system to have maximum flexibility. Moreover smart and transparent wireless connectivity provides the user terminal with fast and seamless transition among Access Points (APs). Different AR navigation approaches have been studied: [Olwal 2006], [Elmqvist et al.] and [Newman et al.] work indoors while [Bell et al. 2002] and [Reitmayr and Drummond 2006] are employed outdoors. Accurate tracking and registration is still an open issue and recently it has mostly been tackled by no single method, but mostly through aggregation of tracking and localization methods, mostly based on handheld AR. A truly wearable, HMD based mobile AR navigation aid for both indoors and outdoors with rich 3D content remains an open issue and a very active field of multi-discipline research.

In this paper, we present a simple and robust mixed reality (MR) framework that allows for real-time interaction with virtual humans in mixed reality environments under consistent illumination. We will look at three crucial parts of this system: interaction, animation and global illumination of virtual humans for an integrated and enhanced presence. The interaction system comprises of a dialogue module, which is interfaced with a speech recognition and synthesis system. Next to speech output, the dialogue system generates face and body motions, which are in turn managed by the virtual human animation layer. Our fast animation engine can handle various types of motions, such as normal key-frame animations, or motions that are generated on-the-fly by adapting previously recorded clips. Real-time idle motions are an example of the latter category. All these different motions are generated and blended on-line, resulting in a flexible and realistic animation. Our robust rendering method operates in accordance with the previous animation layer, based on an extended for virtual humans precomputed radiance transfer (PRT) illumination model, resulting in a realistic rendition of such interactive virtual characters in mixed reality environments. Finally, we present a scenario that illustrates the interplay and application of our methods, glued under a unique framework for presence and interaction in MR.

In this paper, we present a simple and robust mixed reality (MR) framework that allows for real-time interaction with virtual humans in real and virtual environments under consistent illumination. We look at three crucial parts of this system: interaction, animation and global illumination of virtual humans for an integrated and enhanced presence. The interaction system comprises of a dialogue module, which is interfaced with a speech recognition and synthesis system. Next to speech output, the dialogue system generates face and body motions, which are in turn managed by the virtual human animation layer. Our fast animation engine can handle various types of motions, such as normal key-frame animations, or motions that are generated on-the-fly by adapting previously recorded clips. All these different motions are generated and blended on-line, resulting in a flexible and realistic animation. Our robust rendering method operates in accordance with the previous animation layer, based on an extended for virtual humans precomputed radiance transfer (PRT) illumination model, resulting in a realistic display of such interactive virtual characters in mixed reality environments. Finally, we present a scenario that illustrates the interplay and application of our methods, glued under a unique framework for presence and interaction in MR

This paper presents an innovative 3D reconstruction of ancient fresco paintings through the real-time revival of their fauna and flora, featuring groups of virtual animated characters with artificial-life dramaturgical behaviours in an immersive, fully mobile augmented reality (AR) environment. The main goal is to push the limits of current AR and virtual storytelling technologies and to explore the processes of mixed narrative design of fictional spaces (e.g. fresco paintings) where visitors can experience a high degree of realistic immersion. Based on a captured/real-time video sequence of the real scene in a video-see-through HMD set-up, these scenes are enhanced by the seamless accurate real-time registration and 3D rendering of realistic complete simulations of virtual flora and fauna (virtual humans and plants) in a real-time storytelling scenario-based environment. Thus the visitor of the ancient site is presented with an immersive and innovative multi-sensory interactive trip to the past. Copyright © 2005 John Wiley & Sons, Ltd.

Although graphical human modeling has been a long sought subject in computer graphics, when it comes to dealing with real-time applications, it raises a number of unique requirements for both CG artists and researchers. For example, for a real-time performance it is highly desirable to lighten the geometry and optimize the runtime animation of characters wherever possible. An important need in such systems is to assist the CG artists in seamlessly transforming their modeling work from CG packages to the real-time application, without limiting their expressivity. In this paper we describe techniques by which dressed human characters are modeled, loaded into VR scenes, and simulated in real-time. In doing so, we point out challenging issues and solutions that such tasks imply at each phase of modeling and simulation. In particular, we turn our attention to what we consider as key technical components: body and clothes. Case studies show that our modelers successfully meet the need of real-time requirements over a wide variety of scenarios.

We present the architecture of the VHD++ real-time development framework that after several years of intensive research, design, and development effort has been released and enters its validation phase. We discuss the key aspects involved in architectural structure, design and practical implementation of an efficient, flexible and extendible real-time software framework based on the modern 3D game-engine design principles. This framework supports researchers and application developers with rapid, component based development of VR/AR systems featuring advanced virtual character simulation technologies. The discussion covers motivation, main concepts, survey of related work, the main functional and design requirements, design principles and key architectural elements. It concludes with the initial validation results including overview of existing VHD++ based VR/AR virtual character simulation applications.