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Item View-dependent Hierarchical Rendering of Massive Point Clouds through Textured Splats(The Eurographics Association, 2019) Comino Trinidad, Marc; Calaf, Antonio Chica; Gran, Carlos Andújar; Casas, Dan and Jarabo, AdriánNowadays, there are multiple available range scanning technologies which can capture extremely detailed models of realworld surfaces. The result of such process is usually a set of point clouds which can contain billions of points. While these point clouds can be used and processed offline for a variety of purposes (such as surface reconstruction and offline rendering) it is unfeasible to interactively visualize the raw point data. The most common approach is to use a hierarchical representation to render varying-size oriented splats, but this method also has its limitations as usually a single color is encoded for each point sample. Some authors have proposed the use of color-textured splats, but these either have been designed for offline rendering or do not address the efficient encoding of image datasets into textures. In this work, we propose extending point clouds by encoding their color information into textures and using a pruning and scaling rendering algorithm to achieve interactive rendering. Our approach can be combined with hierarchical point-based representations to allow for real-time rendering of massive point clouds in commodity hardware.Item A Virtual Reality Front-end for City Modeling(The Eurographics Association, 2019) Rando, Eduard; Andujar, Carlos; Patow, Gustavo A.; Casas, Dan and Jarabo, AdriánCurrent tools for city modeling, including those supporting procedural techniques, have a steep learning curve and require substantial user input and/or skills to create realistic 3D models of cities. In this paper we propose a VR tool for the fast and intuitive creation of 3D models of cities through their main elements (buildings, blocks and streets). The key ingredients of our approach are: (a) intuitive creation of mass volume models for buildings, whose facades can be refined later on through procedural rules, (b) the ability to use arbitrary urban layouts, either created from scratch within the tool or imported from public map services, (c) algorithms to replicate and transfer user-generated blocks to arbitrary block shapes, so that a few template blocks suffice to cover the whole urban layout. The major benefit of our approach is that city design and inspection tasks are done simultaneously in a completely immersive environment.Item Generation Process of Intrinsic Images Dataset Through Physically-based Rendering(The Eurographics Association, 2021) Rodríguez, Ignacio Moral; López, Alfonso; Jiménez-Perez, J. Roberto; Feito, Francisco R.; Ortega, Lidia; Jurado, Juan M.; Ortega, Lidia M. and Chica, AntonioEl problema denominado Intrinsic Image Decomposition sigue siendo un desafío por resolver en informática gráfica. Aunque el uso de arquitecturas de aprendizaje profundo supondría un avance significativo, los conjuntos de datos de entrenamiento utilizados son aún reducidos. En este estudio se presenta una metodología para la generación de imágenes y su descomposición en varios canales haciendo uso del motor de renderizado Mitsuba2. Para ello, se ha modelado un escenario natural en el que coexisten distintos tipos de vegetación sobre un terreno. En torno a este escenario, se define una trayectoria sobre la que orbita la cámara para generar un conjunto de imágenes desde distintos puntos de vista de forma automática. Como resultado, se proporcionan conjuntos de datos obtenidos a partir de entornos naturales sintéticos formados por las siguientes capas para cada imagen: mapa de normales, iluminación, albedo y mapa de profundidad. Este desarrollo supone un punto de partida para el estudio del cálculo de la iluminación en entornos reales complejos mediante enfoques basados en aprendizaje profundo.Item Development of a Node-Based Material Editor(The Eurographics Association, 2022) Leiro, Luciano Suaya; Garrigó, Marc; Posada, Jorge; Serrano, AnaMaterials systems are an important element within the development of a renderer for an application such as a video game. Nowadays, the method to build a graphic style for a product involving a real-time engine implies a rendering system supporting a solid and concise materials system, as those well-established in real-time engines such as Unreal or Unity. This study presents an open-source application to serve as an editor of materials consisting of a modern real-time renderer. The application consists of a basic OpenGL real-time rendering engine to visualise 3D geometry and its appearance through the support of a node-based material editor to assemble materials in an intuitive and simple manner, without the use of programming and little technical knowledge. The culmination of the project and the achievement of its objectives was satisfactory. We concluded that this work can be used as a reference to understand real-time material systems and renderers and its state of the art in the video games industry.Item A GPU-accelerated LiDAR Sensor for Generating Labelled Datasets(The Eurographics Association, 2021) López, Alfonso; Anguita, Carlos Javier Ogayar; Higueruela, Francisco Ramón Feito; Ortega, Lidia M. and Chica, AntonioThis paper presents a GPU-based LiDAR simulator to generate large datasets of ground-truth point clouds. LiDAR technology has significantly increased its impact on academic and industrial environments. However, some of its applications require a large amount of annotated LiDAR data. Furthermore, there exist many types of LiDAR sensors. Therefore, developing a parametric LiDAR model allows simulating a wide range of LiDAR scanning technologies and obtaining a significant number of points clouds at no cost. Beyond their intensity data, these synthetic point clouds can be classified with any level of detail.Item A Level-of-Detail Technique for Urban Physics Calculations in Large Urban Environments(The Eurographics Association, 2019) Novoa, David Muñoz; Besuievsky, Gonzalo; Patow, Gustavo; Casas, Dan and Jarabo, AdriánIn many applications, such as urban physics simulations or the study of the solar impact effects at different scales, complex 3D city models are required to evaluate physical values. In this paper we present a new technique which, through the use of an electrical analogy and the calculation of sky view factors and form factors, allows to simulate and study the thermal behaviour of an urban environment, taking into account the solar and sky radiation, the air and sky temperatures, and even the thermal interaction between nearby buildings. We also show that it is possible, from a 3D recreation of a large urban environment, to simulate the heat exchanges that take place between the buildings of a city and its immediate surroundings. In the same way, taking into account the terrestrial zone, the altitude and the type of climate with which the simulations are carried out, it is possible to compare the thermal behaviour of a large urban environment according to the chosen conditions.