Abstract
Procedural modeling techniques reduce the effort of creating large virtual cities. However, current methodologies do not allow direct user control over the generated models. Associated with this problem, we face the additional problem related to intrinsic ambiguity existing in user selections. In this paper, we propose to address this problem by using a genetic algorithm to generalize user-provided point-and-click selections of building elements. From a few user-selected elements, the system infers new sets of elements that potentially correspond to the user's intention, including the ones manually selected. These sets are obtained by queries over the shape trees generated by the procedural rules, thus exploiting shape semantics, hierarchy and geometric properties. Our system also provides a complete selection-action paradigm that allows users to edit procedurally generated buildings without necessarily explicitly writing queries. The pairs of user selections and procedural operations (the actions) are stored in a tree-like structure, which is easily evaluated. Results show that the selection inference is capable of generating sets of shapes that closely match the user intention and queries are able to perform complex selections that would be difficult to achieve in other systems. User studies confirm this result.

Abstract
The growing demand for virtual urban models in emerging areas of interest has promoted a variety of techniques for automating the creation of virtual scenes with a high level of realism. However, visualization is not always the only aim in many applications. Increasingly, urban systems are also required for management, analysis, or interaction with very different types of information. Three-dimensional (3D) urban entities should maintain neighbor relations, and being inserted in a geospatial database in order to enable associative queries, one of the most important features associated with 3D urban geographic information system (GIS). Additional challenges are found when these three-dimensional models are implemented in web-based systems. This paper proposes a method for automatic modeling of buildings and street surfaces of entire real cities by combining computer graphics, computational geometry, and GIS techniques. The sources of information employed are two-dimensional (2D) GIS and its associated digital elevation models (DEMs) in order to provide real terrain features. The virtual environment supports web-based navigation and data interaction. The case study was performed in Jaen, Spain, a hilly city with more than 1,000 blocks of buildings. The 3D city model was generated using the public data provided by the general cadastral office of Jaen and the DEM information of this area. The topological relations between the geometric urban entities were inserted in the spatial database and the graphics and thematic information could be accessed through the Internet. All these features are highly desirable for decision making in urban planning. DOI: 10.1061/(ASCE)UP.1943-5444.0000131. (C) 2013 American Society of Civil Engineers.

Abstract
Augmented reality has seen a fast-growing gain of interest in the last few decades. Due to technological advances, smartphones are now devices that allow to experience augmented reality systems, anytime and anywhere. Although its emerging success among users, some problems AR have been reported inhibiting its full acceptance in our digital society. The aim of this paper is to present a study about techniques to implement augmented reality systems in the cultural heritage context, including a prototype to test the technology which, based on physical objects that belong to the landscape, present an effective and accurate augmented reality approach, overlaying 3D virtual models aligned over the real images, using a smartphone's camera.

Abstract
The use of augmented reality has a great potential applied to several areas, in particular, for cultural heritage context where it became possible to display, in loco, virtual elements which complement the user's real scenario. Due to technological advances, differentiated ways of experience this technology has been explored, providing to common user, the access to this technology, until recently, quite limited, especially, in public locations. This article presents a work which includes implementation and evaluation of distinct applications of augmented reality - using smartphones - based on different techniques and tools. The evaluation intends to identify a solution to be implemented in a cultural heritage context, namely, the ruins of the Museu Monografico de Conimbriga

Abstract
Physical maps of a city or region are important pieces of geographical information for tourists and local citizens. Unfortunately the amount of information that can be presented on a piece of paper is limited. In order to extend the map information we propose an augmented reality (AR) system, ARTourMap, for additional information visualization and interaction. This system provides an abstraction layer to develop applications based on the concept of separated logic map tiles taking advantage of a multi-target system where several regions of the map trigger different superimposed graphics. This allows the map to be folded, to be partially occluded, and to have dematerialized information. To demonstrate the proposed system ARTourMap, three layers were developed: a location-based game with points of interest (POIs), a 3D building visualization and an historical map layer. © 2016 The Eurographics Association.

Abstract
Teaching complex assembly and maintenance skills to human operators usually requires extensive reading and the help of tutors. In order to reduce the training period and avoid the need for human supervision, an immersive teaching system using spatial augmented reality was developed for guiding inexperienced operators. The system provides textual and video instructions for each task while also allowing the operator to navigate between the teaching steps and control the video playback using a bare hands natural interaction interface that is projected into the workspace. Moreover, for helping the operator during the final validation and inspection phase, the system projects the expected 3D outline of the final product. The proposed teaching system was tested with the assembly of a starter motor and proved to be more intuitive than reading the traditional user manuals. This proof of concept use case served to validate the fundamental technologies and approaches that were proposed to achieve an intuitive and accurate augmented reality teaching application. Among the main challenges were the proper modeling and calibration of the sensing and projection hardware along with the 6 DoF pose estimation of objects for achieving precise overlap between the 3D rendered content and the physical world. On the other hand, the conceptualization of the information flow and how it can be conveyed on-demand to the operator was also of critical importance for ensuring a smooth and intuitive experience for the operator.