Learning Style Compatibility Between Objects in a Real‐World 3D Asset Database

Large 3D asset databases are critical for designing virtual worlds, and using them effectively requires techniques for efficient querying and navigation. One important form of query is search by style compatibility: given a query object, find others that would be visually compatible if used in the same scene. In this paper, we present a scalable, learning‐based approach for solving this problem which is designed for use with real‐world 3D asset databases; we conduct experiments on 121 3D asset packages containing around 4000 3D objects from the Unity Asset Store. By leveraging the structure of the object packages, we introduce a technique to synthesize training labels for metric learning that work as well as human labels. These labels can grow exponentially with the number of objects, allowing our approach to scale to large real‐world 3D asset databases without the need for expensive human training labels. We use these synthetic training labels in a metric learning model that analyzes the in‐engine rendered appearance of an object—combining geometry, material, and texture—whereas prior work considers only object geometry, or disjoint geometry and texture features. Through an ablation experiment, we find that using this representation yields better results than using renders which lack texture, materiality, or both.     

A hypermedia authoring tool for augmented and virtual reality

Most existing hypermedia authoring systems are intended for use on desktop computers. These systems are typically designed for the creation of 2D documents and therefore employ 2D authoring mechanisms. In contrast, authoring systems for nontraditional multimedia/hypermedia experiences for 3D virtual or augmented worlds focus mainly on creating separate media objects and embedding them within the user's surroundings. As a result, linking these media objects to create 3D hypermedia is a tedious manual task. To address this issue, we present an authoring tool for creating and editing linked 3D hypermedia narratives that are interwoven with a wearable computer user's surrounding environment. Our system is designed for use by authors who are not programmers, and allows them to preview their results on a desktop workstation, as well as with an augmented or virtual reality system.     

Simultaneous Graphic Generalization of Vector Data Sets

Manual cartographic generalization is a simultaneous process. However, most automatic approaches so far have been sequential; generalization operators are applied one at a time in a certain order. This has been the case both for model generalization (generalization of the conceptual model) and graphic generalization. Our research seeks to demonstrate that the graphic part of cartographic generalization can be formulated as an optimization problem and accordingly be solved in a single step. This paper deals with several issues regarding this optimization approach. Firstly, a set of appropriate analytical constraints for the generalization process is given, as well as rules for when to apply these constraints. In our approach, we are limited to formulating these constraints on point locations. Secondly, least-squares adjustment is proposed to find the optimal solution according to the constraints. Finally, the conjugate-gradients method is recommended for solving the normal equations. A prototype system for simultaneous graphic generalization has been implemented in C++, which communicates with a commercial map production system. Results from three tests of the prototype system are included in the paper.     

Virtual worlds in competitive contexts: Analyzing eSports consumer needs

More recently, 3D graphical environments on the Internet, that is virtual worlds, have moved to the center of scientific interest. Since virtual worlds are suggested to mold social computing, research has predominately focused on collaborative virtual worlds. Yet, virtual worlds increasingly move to competitive environments leaving operating businesses with the question as to what to offer in order to fulfill customers’ needs. To close this knowledge gap, we examine competitive virtual worlds in terms of eSports services intrinsically tying cooperation and competition; we illuminate competitive and hedonic need gratifications of continuous eSports use. We apply Uses and Gratifications theory reporting on ten in-depth expert interviews as well as survey data collected from 360 eSports players. We reveal that both competitive (competition and challenge) and hedonic need gratifications (escapism) drive continuous eSports use.     

Using 3D sound as a navigational aid in virtual environments

As current virtual environments are less visually rich than real-world environments, careful consideration must be given to their design to ameliorate the lack of visual cues. One important design criterion in this respect is to make certain that adequate navigational cues are incorporated into complex virtual worlds. In this paper we show that adding 3D spatialized sound to a virtual environment can help people navigate through it. We conducted an experiment to determine if the incorporation of 3D sound (a) helps people find specific locations in the environment, and (b) influences the extent to which people acquire spatial knowledge about their environment. Our results show that the addition of 3D sound did reduce time taken to locate objects in a complex environment. However, the addition of sound did not increase the amount of spatial knowledge users were able to acquire. In fact, the addition of 3D auditory sound cues appears to suppress the development of overall spatial knowledge of the virtual environment.     

Understanding the Role of Sense of Presence and Perceived Autonomy in Users' Continued Use of Social Virtual Worlds

Despite an exponentially increasing number of registered users, social virtual worlds have the problem of a high user attrition rate. It is thus meaningful to explore which factors influence users' continued use of social virtual worlds. The current study attempts to find these factors in unique characteristics (e.g., 3‐dimentional environment, avatar interaction, and user empowerment) in the world, which can be sources for retaining users. Specifically, the study employs the sense of presence and perceived autonomy. 194 users of Second Life, which is the largest social virtual world, participated in the survey. The findings support the argument that the sense of presence and autonomy are influential in users' continued use of social virtual worlds.     

A domain-oriented end-user design environment for generating interactive 3D virtual chemistry experiments

Three-dimensional virtual worlds are potentially feasible for building virtual educational environments. However, educators face technical challenges to apply these technologies because creating virtual educational environments based on virtual worlds demands 3D modeling and programming skills. This paper proposes a method to lower the technical barriers through domain-oriented interfaces with languages and environments that are familiar to educators. A domain-oriented end-user design environment, iVirtualWorld, is designed and developed to implement the proposed method in a specific educational domain, namely introductory chemistry experiments. This web-based environment provides end-users with domain-oriented building blocks, which can be assembled to create 3D virtual chemistry experiments. A usability evaluation and a comparative case study are designed to evaluate the system among chemistry educators, who are the target audience. The usability evaluation contains a task requiring participants to create a 3D virtual chemistry experiment and a voluntary semi-structured interview. The case study compares a virtual experiment generated using iVirtualWorld with an experiment in a commercial virtual chemistry laboratory system. The results show that 1) the domain-oriented end-user design environment enables participants to generate the 3D virtual chemistry experiment within 30 min; 2) participants gain confidence on creating 3D virtual experiments by themselves using iVirtualWorld; 3) participants confirm the usefulness of applying the system in introductory chemistry education; and 4) iVirtualWorld is considered more intuitive and straightforward for students to focus on finishing the experiment without being distracted than the commercial virtual chemistry laboratory system. Areas that can benefit from the system most and areas where the system is less effective are identified by participants. The responses also reveal the limitations of the current system and suggest directions for future improvement.     

A multiuser 3D Web browsing system

The Virtual Realty Modeling Language sets an open-standard file format for designing 3D multimedia and shared virtual worlds on the Internet. VRML was originally designed to support the interaction of multiple participants in the World Wide Web environment, that is, to network virtual worlds via hyperlinks. The development of VRML has spurred broad research on distributed multiuser VR systems. We describe SharedWeb, a 3D Web browsing system that was designed and implemented to support interaction among clients in the existing Web environment. We begin by describing the methodologies and mechanisms used to achieve seamless integration with the Web environment, then we summarize the SharedWeb system implementation. We present some experimental results that show the effects of different frame rates and threshold values on system performance, and conclude with discussions of two virtual worlds currently supported by the system     

Motor planning: An architecture for specifying and controlling the behaviour of virtual actors

As virtual worlds become increasingly complex, task level interaction with virtual actors becomes correspondingly important. The control problem simply becomes unmanageable if we try to interact with synthetic agents at the wrong level of abstraction. However, it is not sufficient merely to implement a set of behaviours for a virtual actor; we require some mechanism for selecting and sequencing motor skills appropriate to the current behavioural goals and the states of other objects and actors in the virtual environment. In this paper we will describe a mechanism for linking perception and action to generate routine behaviours in a process we call motor planning. We present our implementation of the skill network, in which motor skills are the nodes and the arcs represent inhibitory and excitatory connections, including extensions to this architecture based on recent work in robotics. We characterize the domain of motor planning, i.e. what kinds of behaviour can it account for, and when will it fail? We close with a discussion of the limits of our current implementation and work that remains to be done.     

一个基于Java3D的协同虚拟环境工作平台

协同虚拟环境为多用户构造一个可以沉浸其中漫游的虚拟空间,并支持用户之间的协同活动。在军事模拟、远程教育、娱乐等领域有广泛的应用。Java3D是一种高层3D API,可用于快速构建虚拟现实系统。尝试用Java3D技术构造一个协同虚拟环境工作平台原型系统,重点介绍了开发中的技术问题, 讨论了场景建模、消息通信、人机交互、化身控制、白板管理和视频显示等主要功能,并给出了一些具有较高参考价值的代码。     

A Virtual World Grammar for automatic generation of virtual worlds

Hybrid systems such as those that combine 3D virtual worlds and organization based multiagent systems add new visual and communication features for multiuser applications. The design of such hybrid and dynamic systems is a challenging task. In this paper, we propose a system that can automatically generate a 3D virtual world (VW) from an organization based multiagent system (MAS) specification that establishes the activities participants can engage on. Both shape grammar and virtual world paradigms inspired us to propose a Virtual World Grammar (VWG) to support the generation process of a virtual world design. A VWG includes semantic information about both MAS specification and shape grammar elements. This information, along with heuristics and validations, guides the VW generation producing functional designs. To support the definition and execution of a Virtual World Grammar, we have developed a so named Virtual World Builder Toolkit (VWBT). We illustrate this process by generating a 3D visualization of a virtual institution from its specification.     

The cyclic Douglas–Rachford algorithm with r-sets-Douglas–Rachford operators

The Douglas–Rachford (DR) algorithm is an iterative procedure that uses sequential reflections onto convex sets and which has become popular for convex feasibility problems. In this paper we propose a structural generalization that allows to use r-sets-DR operators in a cyclic fashion. We prove convergence and present numerical illustrations of the potential advantage of such operators with r>2 over the classical 2-sets-DR operators in a cyclic algorithm.     

Automated processing for map generalization using web services

In map generalization various operators are applied to the features of a map in order to maintain and improve the legibility of the map after the scale has been changed. These operators must be applied in the proper sequence and the quality of the results must be continuously evaluated. Cartographic constraints can be used to define the conditions that have to be met in order to make a map legible and compliant to the user needs. The combinatorial optimization approaches shown in this paper use cartographic constraints to control and restrict the selection and application of a variety of different independent generalization operators into an optimal sequence. Different optimization techniques including hill climbing, simulated annealing and genetic deep search are presented and evaluated experimentally by the example of the generalization of buildings in blocks. All algorithms used in this paper have been implemented in a web services framework. This allows the use of distributed and parallel processing in order to speed up the search for optimized generalization operator sequences.

Understanding use continuance in virtual worlds: Empirical test of a research model

We decided to examine why people continue to use virtual worlds by studying a real example: the popular virtual world of Second Life. This involved building and testing a model of virtual worlds based on habit from both the habit/automaticity and instant automaticity perspectives, the latter based on utilitarian and hedonic goals. The results (for a sample of 339 users) suggested that continuance intention for the virtual world was driven by perceived usefulness, enjoyment, and both perspectives of automatic behavior, which together provide considerable explanatory power for both habit and continuance intention. We conclude with implications for practice in this new area of inquiry.     

3D-freehand-pose initialization based on operator’s cognitive behavioral models

Tracking, recognition and interaction based on 3D freehand are a part of our virtual assembly system, in which monocular camera is used to input online freehand videos and the hand pose tracker requires a reliable initial pose in the first frame. A novel approach to initializing 3D pose and position of freehand is put forward in this paper visualization of 3D hand model and modeling the operators’ cognitive behaviors. Our approach is composed of three phases: hand posture recognition, coarse-tuning and fine-tuning. The operator moves his/her hand onto the to meet the needs of our virtual assembly system. The main contribution of this paper is that the three core techniques are for the first time integrated together, including human–computer interaction (HCI) in the process of initializing, projection of the 3D hand model in the period of coarse-tuning time. Then, the computer repeatedly fine-tunes the 3D hand model until the projection of the 3D hand model is completely superimposed onto the operator’s hand image. We focus on exploring and modeling cognitive behavior of operator’s hand upon which we design our initialization algorithm. Our research shows that cognitive behavioral models are not only beneficial to reducing cognitive loads for operators, because it makes the computers cater for the changes of the operators’ hand poses, but also helpful to address high dimensionality of articulated 3D hand model. Our experimental results also show that the approach presented in this paper is easier, more pleasurable and satisfactory experience for the operators. Our initialization system has successfully been applied to our 3D freehand tracking system and a simulation virtual assembly system.     

Measuring virtual wealth in virtual worlds

This article presents pioneering research on measuring virtual wealth in an open virtual world for diagnosing the health of virtual worlds. It proved the existence of an open virtual world by proving the existence of a free choice of virtual currencies for virtual goods between distinct virtual worlds. By discussing the features of open virtual world in a circled networked organization, the article devised a virtual wealth measuring scheme, called Gross Virtual Product (GVP), for any virtual world. Based on this scheme, it suggested an accountability matrix to account for a changing virtual world regarding its total virtual wealth, profitability, user participation and happiness. To demonstrate the suitability of GVP scheme and accountability matrix, the article has conducted a case study on SecondLife.com, which showed the appropriateness of the proposed scheme and matrix. The research made in this article is very important. The proposed measuring scheme and matrix help virtual world participants perceive the possible risks of the participated virtual worlds in advance to make better decisions on virtual business.     

Social virtual world continuance among teens: uncovering the moderating role of perceived aggregate network exposure

Engagement in virtual worlds has become pervasive, particularly among the young. At the same time, the number of virtual environments has increased rapidly. Due to intensifying competition, promoting sustained usage, i.e. continuance, has become a top priority for virtual world operators. Prior research has shown that network externalities play a key role in the adoption of communication technologies. However, a small amount of research has examined the role of network externalities in continued IT usage in general or with respect to the virtual world participation in particular. To fill in this gap, we examine how perceived network externalities affect the continuance of social virtual worlds. To this end, we introduce the concept of perceived aggregate network exposure (PANE). We extend the original information systems (IS) continuance model with perceived enjoyment and position PANE as a moderator. We test the model with data collected from 2134 Finnish Habbo Hotel users and employ structural equation modelling in the analysis. The results demonstrate that PANE moderates the influence of motivational factors on continued use intention and satisfaction.     

A declarative approach to procedural modeling of virtual worlds

With the ever increasing costs of manual content creation for virtual worlds, the potential of creating it automatically becomes too attractive to ignore. However, for most designers, traditional procedural content generation methods are complex and unintuitive to use, hard to control, and generated results are not easily integrated into a complete and consistent virtual world.We introduce a novel declarative modeling approach that enables designers to concentrate on stating what they want to create instead of on describing how they should model it. It aims at reducing the complexity of virtual world modeling by combining the strengths of semantics-based modeling with manual and procedural approaches. This article describes two of its main contributions to procedural modeling of virtual worlds: interactive procedural sketching and virtual world consistency maintenance. We discuss how these techniques, integrated in our modeling framework SketchaWorld, build up to enable designers to create a complete 3D virtual world in minutes. Procedural sketching provides a fast and more intuitive way to model virtual worlds, by letting designers interactively sketch their virtual world using high-level terrain features, which are then procedurally expanded using a variety of integrated procedural methods. Consistency maintenance guarantees that the semantics of all terrain features is preserved throughout the modeling process. In particular, it automatically solves conflicts possibly emerging from interactions between terrain features.We believe that these contributions together represent a significant step towards providing more user control and flexibility in procedural modeling of virtual worlds. It can therefore be expected that by further reducing its complexity, virtual world modeling will become accessible to an increasingly broad group of users.