ABSTRACT:Three-dimensional models with photographic textures have become a usual product for the study and dissemination of elements of heritage. The interest for cultural heritage also includes evolution along time; therefore, apart from the 3D models of the current state, it is interesting to be able to generate models representing how they were in the past. To that end, it is necessary to resort to archive information corresponding to the moments that we want to visualize.This text analyses the possibilities of generating 3D models of surfaces with photographic textures from old collections of analog negatives coming from works of terrestrial stereoscopic photogrammetry of historic buildings. The case studies presented refer to the geometric documentation of a small hermitage (done in 1996) and two sections of a wall (year 2000).The procedure starts with the digitization of the film negatives and the processing of the images generated, after which a combination of different methods for 3D reconstruction and texture wrapping are applied: techniques working simultaneously with several images (such as the algorithms of Structure from Motion -SfM) and single image techniques (such as the reconstruction based on vanishing points). Then, the features of the obtained models are described according to the geometric accuracy, completeness and aesthetic quality. In this way, it is possible to establish the real applicability of the models in order to be useful for the aforementioned historical studies and dissemination purposes.The text also wants to draw attention to the importance of preserving the documentary heritage available in the collections of negatives in archival custody and to the increasing difficulty of using them due to: (1) problems of access and physical conservation, (2) obsolescence of the equipment for scanning and stereoplotting and (3) the fact that the software for processing digitized photographs is discontinued.

Resumen TÍTULO: Reconstrucción virtual del estado previo de una iglesia en ruinas RESUMEN: Los modelos tridimensionales pueden representar tanto los elementos patrimoniales existentes como los ya han dejado de existir. En este proyecto se trata la reconstrucción tridimensional de la iglesia del Monasterio de San Prudencio de Monte Laturce (Clavijo, La Rioja, España) tal como se supone que fue durante el siglo XV. En la actualidad el edificio está arruinado por lo que ha sido necesario realizar una importante reconstrucción virtual basad en hipótesis que han requerido la colaboración de técnicos de diferentes áreas de conocimiento, por ejemplo, se ha contado con un levantamiento topográfico de los restos y del área circundante, datos sobre los materiales e hipótesis arqueológicas y arquitectónicas. Dado que existe información de múltiples fuentes, ha sido necesario incorporar un conjunto de criterios de selección y evaluación de las mismas. Three dimensional virtual models can represent both the existing and the already destroyed architectural heritage. This project deals with the 3D reconstruction and representation of the church of San Prudencio's Monastery in La Rioja (Spain) as it is supposed to be during the 15th century. Today the monument is totally in ruins; hence severe reconstruction was needed. This is an exemplary project of close collaboration of different scientific fields. Surveying data of the monument itself and of the wider area around it, but also architectural and archaeological data were collected in situ. It was not possible from the current situation to conclude about the exact form, style and representation of the monument; hence a large part of the project is based on assumptions which have a sound scientific base. Because of the multisource data there was need to define specific criteria by which every data source was evaluated. Está permitido citar y extractar brevemente el texto, siempre que la fuente sea claramente identificada. / Permision is granted to quote short excerpts from this text, provided that the source of such material is fully acknowledged.:AUTORS EDITOR: Los derechos de este texto corresponden a la editorial (Springer Berlin Heidelberg). Conforme a los derechos firmados con la editorial (se incluye copia del contrato), el texto que se incluye en este documento es la versión final previa la formateado de la editorial y está depositado en el repositorio institucional de los autores. / This text is under copyright (Springer Berlin Heidelberg). According to the rights-transfer signed with the publisher (see the attached copy of the contract), the version provided here is the final one but without the formatting given by the book; it is located in the authors' institutional repository.:PUBLISHER OTROS:Las imágenes y planos corresponden a proyectos de documentación realizados por encargo y, en consecuencia, su uso comercial puede infringir derechos de explotación de los promotores. / Pictures and plans come for the documentation of commissioned projects, therefore, thei...

En el debate sobre el empleo de redes sociales y/o repositorios institucionales para difundir los trabajos e investigaciones relativos al patrimonio cabe incluir una reflexión sobre los modelos 3D. La existencia de plataformas comerciales específicas para el almacenamiento, visualización interactiva y descarga (gratuita o de pago) es, hoy por hoy, una actividad pujante, siendo un claro ejemplo de ello, Sketchfab®. Frente a esta línea de acción, los repositorios institucionales, así como los agregadores (como es el caso de Europeana) también están dando pasos en la dirección de considerar este tipo de documentos y aportar funcionalidad a los usuarios para que puedan localizarlos y reutilizarlos de manera conveniente. El presente texto, expone brevemente la situación de ambas líneas y reflexiona sobre las posibilidades de utilización combinada que, a nivel interno, puede emplear una organización cultural con el fin de obtener el máximo rendimiento.

<p class="VARAbstract">The concept of mock-up, which share with the drawing the expressive synthesis for the analysis of the architectural form and evolution, is an invaluable asset for the preservation of the heritage. To mark the 175^th anniversary of the Práxedes Mateo Sagasta’s secondary school of Logroño (Spain), an exhibition about the history of the institution was organized at the premises of La Rioja Library. The current school building became operational in 1900 and was built on the former site of a Carmelite convent. In fact, the convent rooms were the first location for the school, after the expropriations of religious communities during the mid-19th century. For the benefit of the aforementioned exhibition, it was considered interesting to generate a three-dimensional (3D) virtual reconstruction of the convent buildings to show how it would have looked. However, the lack of sufficient contemporary graphic information was a challenge, so it was decided that an efficient solution would be to generate the virtual reconstruction from a paper craft model, which had been created by the librarian of the secondary school as a result of his research on this matter. This text describes the 3D modelling of that cut-out element by means of monoscopic photogrammetry (perspective drawing) and the use of non-realistic rendering based on the appearance of the paper mock-up (and not trying to recreate the real image of the buildings) so as to provide a suggestive view of the convent and create interactive exhibition items. Moreover, the text deals with the long-term preservation and the improvement of the re-use of the 3D models. The former by resorting to institutional repositories —from which users can download the full detailed versions— and the latter employing versions able to be visualized in 3D warehouses (such as Sketchfab) and augmented reality (AR) applications.</p><p><strong>Highlights:</strong></p><ul><li><p>A significant part of the architectural heritage is represented by mock-ups of different materials (paper, wood, metal and so on).</p></li><li><p>Virtual modelling and augmented reality (AR) can be appropriate tools for materializing, recovering and disseminating scale models to the public.</p></li><li><p>Techniques for geometric documentation and visual representation need to be adapted in order to tackle the peculiar features of these elements (size, materials, fragility, etc.).</p></li></ul>