Search Results

Now showing 1 - 3 of 3
  • 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, Adrián
    Nowadays, 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, Adrián
    Current 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
    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, Adrián
    In 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.