This article presents a methodology to process information from a Terrestrial Laser Scanner (TLS) from three dimensions (3D) to two dimensions (2D), and to two dimensions with a color value (2.5D), as a tool to document and analyze heritage buildings. Principally focused on the loss of material in stone, this study aims at creating an evaluation method for loss control, taking into account the state of conservation of a building in terms of restoration, from studying the pathologies, to their identification and delimitation. A case study on the Cathedral of the Seu Vella de Lleida was completed, examining the details of the stone surfaces. This cathedral was affected by military use, periods of abandonment, and periodic restorations.

This article presents a methodology to process information from a Terrestrial Laser Scanner (TLS) from three dimensions (3D) to two dimensions (2D), and to two dimensions with a color value (2.5D), as a tool to document and analyze heritage buildings. Principally focused on the loss of material in stone, this study aims at creating an evaluation method for loss control, taking into account the state of conservation of the building in terms of restoration, from studying the pathologies, to their identification and delimitation. A case study on the Cathedral of the Seu Vella de Lleida was completed, examining the details of the stone surfaces. This cathedral was affected by military use, periods of abandonment, and periodic restorations.

This article intends to explore the limits of scanning with the technology of 3D Laser Scanner and the 3D printing, as an approximation to its application for the survey and the study of singular elements of the architectural heritage. The case study we developed is the Porta del Drac, in the Pavelló Güell, designed by Antoni Gaudí. We divided the process in two parts, one about how to scan and optimize the survey with the Laser Scanner Technology, made with a Faro Forus3D x330 scanner. The second one, about the optimization of the survey as a high-resolution mesh to have a scaled 3D model to be printed in 3D, for the musealization of the Verdaguer House of Literature in Vil.la Joana (Barcelona), a project developed by the Museum of History of Barcelona, in tribute to Jacint Verdaguer. In the first place, we propose a methodology for the survey of this atypical model, which is of special interest for several factors: the geometric complexity in relation to the occlusions, the thickness of the metallic surfaces, the hidden internal structure partially seen from the outside, the produced noise in its interior, and the instrumental errors. These factors make the survey process complex from the data collection, having to perform several scans from different positions to cover the entire sculpture, which has a geometry composed of a variety of folds that cause occlusions. Also, the union of the positions and the average of the surfaces is of great relevance, since the elements of the sculpture are constructed by a metal plate of 2mm, therefore, the error in the union of all these many positions must be smaller than this. Moreover, optimization of the cloud has a great difficulty because of the noise created by the instrumental error as it is a metal sculpture and because of noise point clouds that are generated inside the internal folds of the wings, which are made with a welded wire mesh with little spaces between them. Finally, the added difficulty that there is an internal structure between elements of the parts of the Drac that are partially hidden and therefore cannot be recorded. Secondly, we expose the procedures performed to move from a point cloud to an optimal high-resolution mesh to be printed in 3D, adapting it to all the limitations that this printing technique entails. On the one hand, for the meshing process, a previous classification of the point cloud by pieces (wings, chains, mosaics, head ...) is made and an internal structure is re-assembled to avoid floating parts. On the other hand, the selection of the 3D printing technique, in this case FDM (Fused Deposition Modelling), limits the size of the model so it needs to be cut by determined maximum dimension, and also it limits the minimum thickness of the model's surface, that is to say, the model cannot be directly scaled to the desired size because the 2mm surfaces would be too thin to be printed. This research intends to advance the knowledge of data acquisition, optimization, modelling and 3D printing, with a case study of great complexity. A process that can be systematized and applied to other models.

Building Information Modeling (BIM) has become a must in architecture when it comes to new buildings, but in heritage buildings and in rehabilitation projects, it is still a debate if it’s useful or efficient to make a BIM model. In this paper we analyze and propose When, How and Why modeling in BIM should be a standard process for rehabilitation projects in which an architectural has been performed. In the field of heritage architecture, archeology and rehabilitation, to create an as-built model to work on, it is needed an architectural survey using a laser scan or/and photogrammetry, which captures dense 3D measurements of the building, so architects can make studies of its geometry, detect pathologies and use it as a base for their new designs. However, even though the 3D surveying technics has evolved in the recent years, in the world architecture, the point clouds are still pretty unknown, therefore for many architects are useless information in that format. So, it is necessary to convert this 3D information as point clouds to a more common file like 2D vector drawings in CAD. For this process, it should be question if and how modeling in BIM from the point cloud (scan to BIM) helps to this purpose, without taking into the account that modeling in BIM you get a BIM model, which in rehabilitation and heritage is still not common enough to work with it. Analyzing the information of the point clouds, the typology of the building, the timings, the precision required, and how works a BIM software (Revit) and its libraries; we conclude that, in some particular projects, as far as technology and architecture field are nowadays, to make a useful documentation for rehabilitation modeling in BIM the building in a specific LoD directly from a point cloud (scan to BIM), it is an upgrade in the process beyond the fact of having a BIM model, that is to say, you can get the same documents, but with better quality results, in a more efficient way and less time spend. We ended up with a list of characteristics a building must have for this scan to BIM process is an efficient step and how this should be performed. This paper explores the efficiency of the Scan to BIM process for specific rehabilitation projects, testing it in two different case studies: a large scale building with repetitive elements (old military hospital in Valencia) and a small one with unique elements (classified single family house in Barcelona).

En el marco del proyecto “Ciudad sin barreras. Herramienta para la avaluación y visualización de la accesibilidad al espacio público, en base a tecnologías TLS, GIS i GPS, dirigido por el profesor Josep Roca Caldera, financiado en el marco de la Convocatoria RecerCaixa 2013, en la temática La casa y la ciudad adaptadas a las persones con discapacidad, se plantea la necesidad de desarrollar metodologías para estudiar la accesibilidad en entornos urbanos.Dada la complejidad de los entornos urbanos y las variantes que se pueden considerar desde la accesibilidad (Del Moral y Delgado, 2010), se propone una metodología para realizar análisis sistemáticos para valorar la accesibilidad de entornos urbanos y generar análisis de rutas específicos, partiendo de una documentación masiva, como es la que se genera a partir de los levantamientos con la Tecnología de Escáner Láser Terrestre, TLS.Estos levantamientos TLS, de nubes de puntos no organizadas se clasifican y estructuran, utilizando una metodología propia, en relación a la información necesaria para un análisis de accesibilidad, en este proceso se utilizan diferentes tipos de análisis como el RANSAC (Schnabel et al., 2007) entre otros.A partir de esta información estructurada se generan capas ráster, con criterios de accesibilidad, que permiten realizar análisis de rutas multicriterio, las cuales son aplicadas a dos casos de estudio urbanos concretos, con características diferenciadas.Como conclusión de estos casos de estudio se plantea una metodología clara, que parte de la clasificación de la nube de puntos, la generación de capas ráster concretas, con parámetros específicos, para obtener los análisis de rutas accesibles, dependiendo de las características de la accesibilidad de cada zona de estudio. En el marc del projecte "Ciutat sense barreres. Eina per a l'avaluació i visualització de l'accessibilitat a l'espai públic, en base a tecnologies TLS, GIS i GPS, dirigit pel professor Josep Roca Caldera, finançat en el marc de la Convocatòria RecerCaixa 2013, en la temàtica La casa i la ciutat adaptades a les persones amb discapacitat, es planteja la necessitat de desenvolupar metodologies per estudiar l'accessibilitat en entorns urbans.Donada la complexitat dels entorns urbans i les variants que es poden considerar des de l'accessibilitat (Del Moral i Delgado, 2010), es proposa una metodologia per a realitzar anàlisis sistemàtiques per valorar l'accessibilitat d'entorns urbans i generar anàlisi de rutes específics, partint de una documentació massiva, com és la que es genera a partir dels aixecaments amb la Tecnologia d'escàner làser Terrestre, TLS.Aquests aixecaments TLS, de núvols de punts no organitzades es classifiquen i estructuren, utilitzant una metodologia pròpia, en relació a la informació necessària per a una anàlisi d'accessibilitat, en aquest procés s'utilitzen diferents tipus d'anàlisi com el RANSAC (Schnabel et al., 2007) entre d'altres.A partir d'aquesta informació estructurada es generen capes ràster, amb criteris d'accessibilitat, que permeten realitzar anàlisis de rutes multicriteri, les quals són aplicades a dos casos d'estudi urbans concrets, amb característiques diferenciades.Com a conclusió d'aquests casos d'estudi es planteja una metodologia clara, que parteix de la classificació del núvol de punts, la generació de capes ràster concretes, amb paràmetres específics, per obtenir les anàlisis de rutes accessibles, depenent de les característiques de l'accessibilitat de cada zona d'estudi. Within the “City without barriers, Tool for evaluation and visualization of accessibility to public space, based on TLS, GIS and GPS Technologies” project, headed by Professor Josep Roca Caldera, funded in the framework of the RecerCaixa 2013 Call, in the theme The house and the city adapted to the disabled people, there is a need to develop methodologies to study accessibility in urban settings.Given the complexity of the urban environments and the variants that can be considered from the accessibility (Del Moral, 2010), it is proposed a methodology to carry out systematic analyzes to evaluate the accessibility of urban environments and generate analysis of specific routes, starting from a massive documentation, based on architectural surveys with Terrestrial Laser Scanner Technology TLS.These TLS surveys of unorganized point clouds are classified and structured, using the methodology proposed in this publication, in relation to the information needed for an accessibility analysis. In this process different types of analysis are used such as the RANSAC algorithm (Schnabel et al., 2007) among others.Based on this structured information, ráster layers are generated, with accessibility criteria, allowing the analysis of multi-criteria routes, which are applied to two specific urban case studies, with differentiated characteristics.As a conclusion of these case studies, a clear methodology is proposed, that starts from the classification of points cloud, the generation of specific ráster layers, with specific parameters, to obtain the analysis of accessible routes, depending on the characteristics of accessibility.

The heritage survey with the Terrestrial Laser Scanner (TLS) allows the document of the geometry of the building and to constitute a 3D point cloud as a register of its conservation state. When complex buildings with architectural and sculptural elements are scanned, there are a lot of captured data that is not valid, because of the instrumental error and foreign elements of the buildings. For that reason, the point cloud must be cleaned with the objective to obtain a final model from which different products could be created, such as plans, technical documents and 3D models to print. For this cleaning process, in this article with the case of study is Antoni Gaudi's Sagrada Familia (Fachada del Nacimiento), we propose a methodology based on applying some filers, considering the fact that more than 3000 positions were realized, 750 of them belong to the same facade with positions that have a lot of overlapping data. Therefore, in a same zone of the building there is data scanned from multiple positions in different ways, so we can find there any kind of error, such as the noise from boundary effects, glass flections and mobile objects, and scans realized from a scissor lift, that have been previously validated. Different point cloud filtering processes have been studied, through the point cloud itself (position by position and with a unitary cloud), and by meshing it. Every process requires the knowledge of how the scan was realized, what type of error dominates in each zone is analyzed. Therefore, each filtering option accomplish the requirements established after the analysis.