Real-time tessellation of terrain on graphics hardware

Synthetic terrain is a key element in many applications, which can lessen the sense of realism if it is not handled correctly. We propose a new technique for visualizing terrain surfaces by tessellating them on the GPU. The presented algorithm introduces a new adaptive tessellation scheme for managing the level of detail of the terrain mesh, avoiding the appearance of t-vertices that can produce visually disturbing artifacts. Previous solutions exploited the geometry shader's capabilities to tessellate meshes from scratch. In contrast, we reuse the already calculated data to minimize the operations performed in the shader units. This feature allows us to increase performance through smart refining and coarsening. Finally, we also propose a framework to manage large DEMs as height maps.This work has been supported by the Spanish Ministry of Science and Technology (projects TIN2009-14103-C03-03, TSI-020400-2009-0133 and TIN2010-21089-C03-03), by the Generalitat Valenciana (project PROMETEO/2010/028), by Bancaja (project P1 1B2010-08) and by ITEA2 (project IP08009

Mensajería instantánea educativa en un entorno 3D

There is a growing interest in researching on teaching methods using the latest technologies. Educational communities are making an effort to promote the generation and use of virtual environments for tutorial sessions, seminars, etc. The aim of this paper is to improve communication between teachers and students by providing new tools for education and training. Our research focuses on how we could have an improved graphical interface for messaging, featuring 3D content into virtual environments to improve the educational interaction. Thus, our proposal is to improve the technological means combining virtual tutoring tools with advanced methods of computer graphics and image processing.Existe un creciente interés en la investigación de métodos docentes que utilicen las nuevas tecnologías. Las comunidades educativas están haciendo un esfuerzo por promover la generación y el uso de entornos virtuales para tutorías, seminarios, etc. El objetivo de este artículo es mejorar la comunicación entre profesores y estudiantes ofreciendo nuevas herramientas para la educación y la formación. Nuestra investigación se centra en cómo podríamos disponer de un interfaz gráfico mejorado para la mensajería, ofreciendo contenido 3D en entornos virtuales para mejorar la interacción educativa. Así, nuestra propuesta es mejorar los medios tecnológicos combinando la tutorización virtual con herramientas y métodos avanzados de gráficos por ordenador y procesamiento de imágenes

P2P TRAFFIC MEASUREMENTS ON THE EMULE

P2P systems are designed for the sharing of computer resources by direct exchange and they are characterized by their ability to adapt to failures and accommodate transient populations of peers while maintaining acceptable connectivity and performance. This paper examines the peer-to-peer file sharing infrastructure by focusing on a content delivery system: the eMule application based on the eDonkey protocol. We present a framework developed to collect data and to offer several measurements of the performance of this P2P network. This process will allow us to study the way clients use eMule with the aim of analyzing whether it is possible to create an overlaid network of communities which would enhance the performance of a P2P application

Incremental guideline formalization with tool support

Abstract. Guideline formalization is recognized as an important component in improving computerized guidelines, which in turn leads to better informedness, lower inter-practician variability and, ultimately, to higher quality healthcare. By means of a modeling exercise, we investigate the role of guideline formalization tools which use two different knowledge transformation principles in producing re-usable knowledge objects useful for representing medical processes and performing updates of medical guidelines. We give a general evaluation of usefulness and state the main requirements for tools that reuse medical knowledge and support authoring of guidelines.

Automatic Terrain Generation with a Sketching Interface

Virtual environments should offer the user a deep interactive experience with both large worlds to explore and a higher degree of perceived realism. The main goal of our work is to provide the final user with an easy-to-use accurate terrain generation application, which allows non-professional users to design their own desired terrain. In this paper we consider the creation of islands to be used in computer games. We introduce a simple terrain algorithm and we also consider its integration into a sketching application. The application will offer both a 2D and a 3D representation of the terrain, in order to simplify the interface and provide the user with more interactive feedback about the island that has been designed. Our framework offers real-time algorithms for both creating and modifying terrain features, thus improving the final results with more realism and greater customization by the user

View-Dependent Multiresolution Modeling on the GPU

For more than a decade, researchers working on level-of-detail techniques have oriented their efforts toward developing better frameworks and adapting their solutions to new hardware. Nevertheless, we believe there is still a gap for efficient yet simple multiresolution models that fully exploit the potential of current GPUs. In this paper we present a level-of-detail framework based on moving the extraction process from updating indices to updating vertices. This feature enables us to perform culling and geomorphing on a vertex basis. Furthermore, it simplifies the update of indices to eliminate degenerate information. The model is capable of offering both uniform and variable resolution and to achieve the latter, a silhouette-based criterion has been included. Finally, we would like to highlight that the model is completely integrated in the GPU and no CPU/GPU communication is necessary once all the information is correctly loaded in hardware memory

View-Dependent Tessellation and Simulation of Ocean Surfaces

Modeling and rendering realistic ocean scenes have been thoroughly investigated for many years. Its appearance has been studied and it is possible to find very detailed simulations where a high degree of realism is achieved. Nevertheless, among the solutions to ocean rendering, real-time management of the huge heightmaps that are necessary for rendering an ocean scene is still not solved. We propose a new technique for simulating the ocean surface on GPU. This technique is capable of offering view-dependent approximations of the mesh while maintaining coherence among the extracted approximations. This feature is very important as most solutions previously presented must retessellate from the initial mesh. Our solution is able to use the latest extracted approximation when refining or coarsening the mesh

Rendering continuous level-of-detail meshes by Masking Strips

In this paper we present a new continuous multiresolution approach which has been developed for the interactive visualization of meshes in real-time applications. Our interest is to offer an efficient solution which considers submeshes, textures, normals and bones for skeletal animations. The model has been designed to give view-independent continuous levels-of-detail and uses triangle strips for exploiting vertex cache and coherence for minimizing bus traffic. Furthermore, its data structures allow for an efficient extraction process where all unnecessary information is eliminated and also for progressive transmission. A new simplification strategy has also been developed, which preserves appearance and attributes. In the results section we present different images to show the visual quality obtained with this simplification method, as well as a study of the storage and rendering costs. © 2009 Elsevier Inc. All rights reserved