A survey of real-time crowd rendering

In this survey we review, classify and compare existing approaches for real-time crowd rendering. We first overview character animation techniques, as they are highly tied to crowd rendering performance, and then we analyze the state of the art in crowd rendering. We discuss different representations for level-of-detail (LoD) rendering of animated characters, including polygon-based, point-based, and image-based techniques, and review different criteria for runtime LoD selection. Besides LoD approaches, we review classic acceleration schemes, such as frustum culling and occlusion culling, and describe how they can be adapted to handle crowds of animated characters. We also discuss specific acceleration techniques for crowd rendering, such as primitive pseudo-instancing, palette skinning, and dynamic key-pose caching, which benefit from current graphics hardware. We also address other factors affecting performance and realism of crowds such as lighting, shadowing, clothing and variability. Finally we provide an exhaustive comparison of the most relevant approaches in the field.Peer ReviewedPostprint (author's final draft

Constrained set-up of the tGAP structure for progressive vector data transfer

A promising approach to submit a vector map from a server to a mobile client is to send a coarse representation first, which then is incrementally refined. We consider the problem of defining a sequence of such increments for areas of different land-cover classes in a planar partition. In order to submit well-generalised datasets, we propose a method of two stages: First, we create a generalised representation from a detailed dataset, using an optimisation approach that satisfies certain cartographic constraints. Second, we define a sequence of basic merge and simplification operations that transforms the most detailed dataset gradually into the generalised dataset. The obtained sequence of gradual transformations is stored without geometrical redundancy in a structure that builds up on the previously developed tGAP (topological Generalised Area Partitioning) structure. This structure and the algorithm for intermediate levels of detail (LoD) have been implemented in an object-relational database and tested for land-cover data from the official German topographic dataset ATKIS at scale 1:50 000 to the target scale 1:250 000. Results of these tests allow us to conclude that the data at lowest LoD and at intermediate LoDs is well generalised. Applying specialised heuristics the applied optimisation method copes with large datasets; the tGAP structure allows users to efficiently query and retrieve a dataset at a specified LoD. Data are sent progressively from the server to the client: First a coarse representation is sent, which is refined until the requested LoD is reached

An Investigation into Animating Plant Structures within Real-time Constraints

This paper is an analysis of current developments in rendering botanical structures for scientic and entertainment purposes with a focus on visualising growth. The choices of practical investigations produce a novel approach for parallel parsing of difficult bracketed L-Systems, based upon the work of Lipp, Wonka and Wimmer (2010). Alongside this is a general overview of the issues involved when looking at growing systems, technical details involving programming for the Graphics Processing Unit (GPU) and other possible solutions for further work that also could achieve the project's goals

Visualization and Animation of a Missile/Target Encounter

Existing missile/target encounter modeling and simulation systems focus on improving probability of kill models. Little research has been done to visualize these encounters. These systems can be made more useful to the engineers by incorporating current computer graphics technology for visualizing and animating the encounter. Our research has been to develop a graphical simulation package for visualizing both endgame and full fly-out encounters. Endgame visualization includes showing the interaction of a missile, its fuze cone proximity sensors, and its target during the final fraction of a second of the missile/target encounter. Additionally, this system displays dynamic effects such as the warhead fragmentation pattern and the specific skewing of the fragment scattering due to missile yaw at the point of detonation. Fly-out visualization, on the other hand, involves full animation of a missile from launch to target. Animating the results of VisSim fly-out simulations provides the engineer a more efficient means of analyzing his data. This research also involves investigating fly-out animation via the World Wide Web

Modeling Construction Equipment in 4D Simulation and Application in VR Safety Training

Enhancing safety and productivity in construction sites is of principal importance, especially in congested sites. Scheduling and visualizing the construction progress in a Four-dimensional (4D) model with a high Level of Detail (LOD) are expected to improve safety, productivity, and constructability in construction sites. In spite of the large number of studies using Building Information Modeling (BIM) for visualization of the construction activities at the macro-level, these research works do not fully consider the scheduling and animating the equipment operations at the micro-level. This study aims to visualize the construction equipment activities to model the erection of a structure with prefabricated components along with other resources, such as workers and temporary equipment. The construction process is modeled in Fuzor Virtual Design and Construction (VDC) and the collision test is run to find the upcoming dangers. In addition, one of the areas where 4D can be used is for safety training. It is expected that the combination of 4D BIM with Virtual Reality (VR) improves the safety knowledge of construction workers, students, and equipment operators. Despite the large number of research works on the use of Three-dimensional (3D) VR in construction training, 4D VR is not sufficiently used for training purposes. This study aims to improve the safety knowledge of construction students by using a VR-based training approach. The specific objectives of the research are: (1) Identifying the requirements for construction equipment modeling and comparing the available commercial and research platforms in terms of visualizing, animating, and simulating equipment movements; (2) Animating and scheduling the construction processes at the micro-level in 4D BIM; and (3) Enhancing and evaluating the safety knowledge of construction management students in terms of Personal Protective Equipment (PPE) and equipment-related hazards using VR. In the first stage, the construction 4D context was developed and the safety scenarios about PPE- and equipment-related hazards were added. Secondly, construction students were given the initial VR-based training regarding hazard scenarios. Then, their safety knowledge was tested and they were asked to express their learning experience. The conclusions of this research are as follows: (1) When equipment tasks are visualized and scheduled at the micro-level in 4D BIM, the conflicts can be detected in advance and the cycle time of equipment can be determined, leading to the improvement of safety, productivity, and constructability in construction sites; (2) VR safety training improves hazard recognition of construction students since they can experience risky conditions in virtual construction sites; and (3) The capability of students in identifying equipment-related hazards would improve when they experience safety risks applied in 4D VR

The ontomedia project : ODR, relational justice, multimedia

More than ever, the Web is a space of social interaction. Recent trends reveal that Internet users spend more time interacting within online communities than in checking and replying to e-mail. Online communities and institutions create new spaces for interaction, but also open new avenues for the emergence of grievances, claims, and disputes. Consequently, online dispute resolution (ODR) procedures are core to these new online worlds. But can ODR mechanisms provide sufficient levels of reputation, trust ,and enforceability so as to become mainstream? This contribution introduces the new approaches to ODR with an emphasis on the Ontomedia Project, which is currently developing a web-based platform to facilitate online mediation in different domains

Meshless Animation Framework

This report details the implementation of a meshless animation framework for blending surfaces. The framework is meshless in the sense that only the control points are handled on the CPU, and the surface evaluation is delegated to the GPU using the tessellation shader steps. The framework handles regular grids and some forms of irregular grids. Different ways of handling the evaluation of the local surfaces are investigated. Directly evaluating them on the GPU or pre-evaluating them and only sampling the data on the GPU. Four different methods for pre-evaluation are presented, and the surface accuracy of each one is tested. The framework contains two methods for adaptively setting the level of detail on the GPU depending on position of the camera, using a view-based metric and a pixel-accurate rendering method. For both methods the pixel-accuracy and triangle size is tested and compared with static tessellation. Benchmarking results from the framework are presented. With and without animation, with different local surface types, and different resolution on the pre-evaluated data

Real-time rendering and simulation of trees and snow

Tree models created by an industry used package are exported and the structure extracted in order to procedurally regenerate the geometric mesh, addressing the limitations of the application's standard output. The structure, once extracted, is used to fully generate a high quality skeleton for the tree, individually representing each section in every branch to give the greatest achievable level of freedom of deformation and animation. Around the generated skeleton, a new geometric mesh is wrapped using a single, continuous surface resulting in the removal of intersection based render artefacts. Surface smoothing and enhanced detail is added to the model dynamically using the GPU enhanced tessellation engine. A real-time snow accumulation system is developed to generate snow cover on a dynamic, animated scene. Occlusion techniques are used to project snow accumulating faces and map exposed areas to applied accumulation maps in the form of dynamic textures. Accumulation maps are xed to applied surfaces, allowing moving objects to maintain accumulated snow cover. Mesh generation is performed dynamically during the rendering pass using surface o�setting and tessellation to enhance required detail

Design and implementation of 3D buildings integration for a Webgl-Based Virtual Globe: a case study of Valencian Cadastre and Fide Building Mode

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.Since nowadays Web applications are increasingly providing plenty of creative and interesting services relying on new standards and more powerful computers, it becomes important to create similar applications, to process and visualize geographic data taking advantage of such groundings. In this context, it results interesting to develop new Web-based geo-processing based on a 3D data representation, exploiting the recent WebGL graphic specification from a client-side point of view. This research explains the novel way in which whole Valencian cadastre was analyzed, processed and finally represented into a WebGL-based virtual globe. These improvements provide end-users firstly, an optimization of computer graphics performance, by natively accessing to graphics instructions; and secondly a functional data management and representation for the present and forthcoming geo-processing Web-based platform