Modelamiento de Objetos 3D

Las escenas tridimensionales generadas hoy en día contienen modelos geométricos altamente detallados; éstas están emergiendo rápidamente como la próxima generación de aplicaciones tales como las basadas en Internet, los complejos ambientes virtuales tridimensionales, el CAD colaborativo, la visualización interactiva y los videojuegos multiusuario, entre otras. Así, se espera que la futura generación de sistemas gráficos computacionales trate con complejos modelos 3D renderizados de manera interactiva y se espera un crecimiento de tales modelos 3D en la red. Esta situación motiva el desarrollo de modelos de volúmenes, representados a través de su superficie y/o de su interior, que puedan satisfacer los requerimientos de uso efectivo de espacio en disco y de ancho de banda de red, así como también una reducción sustancial del tiempo de transferencia sobre la red. Indudablemente, estos modelos plantean rigurosas demandas en lo referente a ancho de banda, capacidad de almacenamiento y tiempo de transmisión. Tradicionalmente, los modelos geométricos de gran complejidad han sido construidos de subdivisiones de modelos de objetos aproximados poligonalmente denominadas redes, o de sistemas de escaneo que pueden producir modelos de gran complejidad con cientos de miles o millones de vértices e información de atributos adicionales a cada uno de ellos tales como el color y las normales. En todos los casos, la representación resultante requiere grandes cantidades de memoria de almacenamiento y grandes tiempos de transmisión y renderizado. Por lo dicho, requerimientos mínimos de un sistema gráfico de software de hoy en día incluyen compresión, multirresolución, simplificación aproximada de redes y transmisión progresiva. El principal objetivo de nuestro trabajo es la construcción de buenos modelos de volúmenes, representados tanto a través de su superficie como de su interior, de modo tal que sea posible una aproximación de alta calidad de grandes cantidades de datos. Estamos trabajando en la obtención de representaciones 3D que soporten multirresolución, transmisión progresiva, compresión, refinamiento electivo y renderizado rápido y eficiente.Eje: Computación gráfica. VisualizaciónRed de Universidades con Carreras en Informática (RedUNCI

Multiple dataset visualization (MDV) framework for scalar volume data

Many applications require comparative analysis of multiple datasets representing different samples, conditions, time instants, or views in order to develop a better understanding of the scientific problem/system under consideration. One effective approach for such analysis is visualization of the data. In this PhD thesis, we propose an innovative multiple dataset visualization (MDV) approach in which two or more datasets of a given type are rendered concurrently in the same visualization. MDV is an important concept for the cases where it is not possible to make an inference based on one dataset, and comparisons between many datasets are required to reveal cross-correlations among them. The proposed MDV framework, which deals with some fundamental issues that arise when several datasets are visualized together, follows a multithreaded architecture consisting of three core components, data preparation/loading, visualization and rendering. The visualization module - the major focus of this study, currently deals with isosurface extraction and texture-based rendering techniques. For isosurface extraction, our all-in-memory approach keeps datasets under consideration and the corresponding geometric data in the memory. Alternatively, the only-polygons- or points-in-memory only keeps the geometric data in memory. To address the issues related to storage and computation, we develop adaptive data coherency and multiresolution schemes. The inter-dataset coherency scheme exploits the similarities among datasets to approximate the portions of isosurfaces of datasets using the isosurface of one or more reference datasets whereas the intra/inter-dataset multiresolution scheme processes the selected portions of each data volume at varying levels of resolution. The graphics hardware-accelerated approaches adopted for MDV include volume clipping, isosurface extraction and volume rendering, which use 3D textures and advanced per fragment operations. With appropriate user-defined threshold criteria, we find that various MDV techniques maintain a linear time-N relationship, improve the geometry generation and rendering time, and increase the maximum N that can be handled (N: number of datasets). Finally, we justify the effectiveness and usefulness of the proposed MDV by visualizing 3D scalar data (representing electron density distributions in magnesium oxide and magnesium silicate) from parallel quantum mechanical simulation

Natural ventilation design attributes application effect on, indoor natural ventilation performance of a double storey, single unit residential building

In establishing a good indoor thermal condition, air movement is one of the important parameter to be considered to provide indoor fresh air for occupants. Due to the public awareness on environment impact, people has been increasingly attentive to passive design in achieving good condition of indoor building ventilation. Throughout case studies, significant building attributes were found giving effect on building indoor natural ventilation performance. The studies were categorized under vernacular houses, contemporary houses with vernacular element and contemporary houses. The indoor air movement of every each spaces in the houses were compared with the outdoor air movement surrounding the houses to indicate the space’s indoor natural ventilation performance. Analysis found the wind catcher element appears to be the most significant attribute to contribute most to indoor natural ventilation. Wide opening was also found to be significant especially those with louvers. Whereas it is also interesting to find indoor layout design is also significantly giving impact on the performance. The finding indicates that a good indoor natural ventilation is not only dictated by having proper openings at proper location of a building, but also on how the incoming air movement is managed throughout the interior spaces by proper layout. Understanding on the air pressure distribution caused by indoor windward and leeward side is important in directing the air flow to desired spaces in producing an overall good indoor natural ventilation performance

Integrated Volume Compression and Visualization

Volumetric data sets require enormous storage capacity even at moderate resolution levels. The excessive storage demands not only stress the capacity of the underlying storage and communications systems, but also seriously limit the speed of volume rendering due to data movement and manipulation. A novel volumetric data visualization scheme is proposed and implemented in this work that renders 2D images directly from compressed 3D data sets. The novelty of this algorithm is that rendering is performed on the compressed representation of the volumetric data without pre-decompression. As a result, the overheads associated with both data movement and rendering processing are significantly reduced. The proposed algorithm generalizes previously proposed whole-volume frequency-domain rendering schemes by first dividing the 3D data set into subcubes, transforming each subcube to a frequency-domain representation, and applying the Fourier Projection Theorem to produce the projected 2D images a..