Web based hybrid volumetric visualisation of urban GIS data: Integration of 4D Temperature and Wind Fields with LoD-2 CityGML models

City models visualisation, buildings, structures and volumetric information, is an important task in Computer Graphics and Urban Planning -- The different formats and data sources involved in the visualisation make the development of applications a big challenge -- We present a homogeneous web visualisation framework using X3DOM and MEDX3DOM for the visualisation of these urban objects -- We present an integration of different declarative data sources, enabling the utilization of advanced visualisation algorithms to render the models -- It has been tested with a city model composed of buildings from the Madrid University Campus, some volumetric datasets coming from Air Quality Models and 2D layers wind datasets -- Results show that the visualisation of all the urban models can be performed in real time on the Web -- An HTML5 web interface is presented to the users, enabling real time modifications of visualisation parameter

Open3D: Crowd-Sourced Distributed Curation of City Models

Detailed, large-scale 3D models of cities are important assets for many applications. While creating such models is difficult and time consuming, keeping them updated is even more challenging. In comparison, in many domains, crowd-sourcing of data is now an established process for expanding the scope or detail of data sets. In this paper, we describe the initial prototype implementation of Open3D, a crowd-sourcing platform for distributed curation of large-scale city models. We present an open architecture with interfaces that clearly separate model storage and indexing from viewing or editing. To support collaborative editing of extremely large models, we propose to use a modeling and model description paradigm that can integrate polygon-based modeling with parametric operations. We demonstrate the main concepts and prototype through an online city model that can be synchronously edited by multiple users, with live changes being propagated among clients. The main implementation consists of a set of web services, which support key functions such as model storage, locks for editing and spatial queries; a light-weight viewer based on the Cesium library, which runs on desktops and mobile devices; and a prototype editor, which clients can install to edit the models

3DRepo4Unity: Dynamic Loading of Version Controlled 3D Assets into the Unity Game Engine

In recent years, Unity has become a popular platform for the development of a broad range of visualization and VR applications. This is due to its ease of use, cross-platform compatibility and accessibility to independent developers. Despite such applications being cross-platform, their assets are generally bundled with executables, or streamed at runtime in a highly optimised, proprietary format. In this paper, we present a novel system for dynamically populating a Unity environment at runtime using open Web3D standards. Our system generates dynamic resources at runtime from a remote 3D Repo repository. This enables us to build a viewer which can easily visualize X3D-based revisions from a version controlled database in the cloud without any compile-time knowledge of the assets. We motivate the work and introduce the high-level architecture of our solution. We describe our new dynamic transcoding library with an emphasis on scalability and 3D rendering. We then perform a comparative evaluation between 3drepo.io, a state of the art X3DOM based renderer, and the new 3DRepo4Unity library on web browser platforms. Finally, we present a number of different applications that demonstrate the practicality of our chosen approach. By building on previous Web3D functionality and standards, our hope is to stimulate further discussion around and research into web formats that would enable incremental loading on other platforms

Cave chamber data modeling and 3D Web visualization

Underground caves and its specific structures are important for geomorphological studies. In this paper we present tools to identify and map speleothems by surveying cave chambers interiors. The cave chamber was surveyed using Terrestrial Laser Scanning to acquire point clouds with high level of detail for 3D model generation. This data with 45 million points is useful for either reconstruction, geomorphological studies or virtual visits of caves. With this point cloud we generated a 3D-mesh to represent the surface model of the cave chamber, which is important to study its geomorphological features. A topological structure of the 3D-mesh was also implemented to get an efficient algorithm to help identifying stalactites. The possibility to publish 3D data on the Web is of particular interest for the geospatial field. For this reason, it was decided to make the cave model available in the Web by developing a 3D graphical interface where users can navigate and interact with the three-dimensional models of the cave. For this Web3D framework it was used X3D, WebGL and X3DOM. Such solution does not require any additional plug-ins or components

High-resolution digital 3D models of Algar do Penico Chamber: limitations, challenges, and potential

The study of karst and its geomorphological structures is important for understanding the relationships between hydrology and climate over geological time. In that context, we conducted a terrestrial laser-scan survey to map geomorphological structures in the karst cave of Algar do Penico in southern Portugal. The point cloud data set obtained was used to generate 3D meshes with different levels of detail, allowing the limitations of mapping capabilities to be explored. In addition to cave mapping, the study focuses on 3D-mesh analysis, including the development of two algorithms for determination of stalactite extremities and contour lines, and on the interactive visualization of 3D meshes on the Web. Data processing and analysis were performed using freely available open-source software. For interactive visualization, we adopted a framework based on Web standards X3D, WebGL, and X3DOM. This solution gives both the general public and researchers access to 3D models and to additional data produced from map tools analyses through a web browser, without the need for plug-ins

A continuous deployment-based approach for the collaborative creation, maintenance, testing and deployment of CityGML models

Georeferenced 3D models are an increasingly common choice to store and display urban data in many application areas. CityGML is an open and standardized data model, and exchange format that provides common semantics for 3D city entities and their relations and one of the most common options for this kind of information. Currently, creating and maintaining CityGML models is costly and difficult. This is in part because both the creation of the geometries and the semantic annotation can be complex processes that require at least some manual work. In fact, many publicly available CityGML models have errors. This paper proposes a method to facilitate the regular maintenance of correct city models in CityGML. This method is based on the continuous deployment strategy and tools used in software development, but adapted to the problem of creating, maintaining and deploying CityGML models, even when several people are working on them at the same time. The method requires designing and implementing CityGML deployment pipelines. These pipelines are automatic implementations of the process of building, testing and deploying CityGML models. These pipelines must be run by the maintainers of the models when they make changes that are intended to be shared with others. The pipelines execute increasingly complex automatic tests in order to detect errors as soon as possible, and can even automate the deployment step, where the CityGML models are made available to their end users. In order to demonstrate the feasibility of this method, and as an example of its application, a CityGML deployment pipeline has been developed for an example scenario where three actors maintain the same city model. This scenario is representative of the kind of problems that this method intends to solve, and it is based on real work in progress. The main benefits of this method are the automation of model testing, every change to the model is tested in a repeatable way; the automation of the model deployment, every change to the model can reach its end users as fast as possible; the systematic approach to integrating changes made by different people working together on the models, including the possibility of keeping parallel versions with a common core; an automatic record of every change made to the models (who did what and when) and the possibility of undoing some of those changes at any time.This work was supported by the Optimised Energy Efficient Design Platform for Refurbishment at District Level (OptEEmAL) project, Grant Agreement Number 680676, 2015-2019, as part of the European Union’s Horizon 2020 research and innovation programme