Dimensions and levels of knowledge in Heritage Building Information Modelling, HBIM: The model of the Charterhouse of Jerez (Cádiz, Spain)

Dimensions and Levels of Knowledge in Heritage Building Information Modelling, HBIM: The model of the Charterhouse of Jerez (C adiz, Spain) Manuel Castellano-Rom an a , * , Francisco Pinto-Puerto b a University of Seville, Dept. of Architectural Graphical Expression, Strategies of Heritage Knowledge (HUM799), Av. Reina Mercedes, 41012, Seville, Spain b University of Seville, Institute of Architecture and Building Science (IUACC), Av. Reina Mercedes, 41012, Seville, Spain ARTICLE INFO Keywords: HBIM BIM Heritage management Architectural heritage Charterhouse of Jerez ABSTRACT Application of Building Information Modelling methodology, BIM, in the field of architectural heritage in recent years has generated a significant catalogue of experiences classified under the title Heritage Building Information Modelling, HBIM. However, these are disparate cases in terms of their scope and purpose without a specified general conceptual framework in which to define each case study. This article proposes a general characterization of HBIM, transferring two BIM concepts originally related to the production and management of new site architecture to the specific context of cultural heritage: BIM Dimensions and Level of Development, LOD, renamed as Level of Knowledge, LOK, for heritage application. According to this conceptual proposal, the HBIM model of the Charterhouse of Jerez has been generated, considering the information required for strategic planning of the main areas of action for heritage management: research, protection, conservation and dissemination. 1. Introduction and objectives The body of knowledge, methodologies, and experiences on documentation through digital graphics of architectural heritage is very broad and continues to evolve, incorporating the methodological innovation of BIM in recent years. The development and progressive generalization of BIM methodology in the AEC sector of the industry is undergoing profound renovation in terms of architectural practice, giving rise to new procedures for the production and management of newly constructed buildings based on the consideration of the building as an integrated and evolutionary system, beginning with the ideation phase, through work execution, until the culmination of its life cycle. In BIM models, information not only refers to its three-dimensional characterization, 3D. In fact, it has been agreed to define BIM dimensions 4D, 5D, 6D and 7D of a model according to the specific information contents that may be associated with it. A 4D model refers to the inclusion of information regarding its time sequencing. A 5D model refers to the inclusion of information regarding costs of model elements. A 6D model refers to the inclusion of information regarding environmental behaviour. And finally, a 7D model refers to the inclusion of information regarding maintenance schedules. The geometric and information complexity that architectural models can achieve requires the definition of concepts that practically describe the level of complexity the model has reached. Around this general idea, different denominations have been created: Level of Detail, Level of Development, Level of Definition, Level of Information of the model. These concepts are associated in a BIM model to the degree of accuracy achieved in the geometric definition and the quantity and reliability of the information associated with an element or project. Despite the apparent simplicity of the concept, multiple interpretations of it have been generated. Nevertheless, a generalized consensus has been established as regards the definition of a sequence of five levels of development: LOD100, LOD200, LOD300, LOD400 and LOD500, in accordance with the proposal of the American Institute of Architects, AIA (American Institute of Architects, 2013). Therefore, the main characteristic of BIM is the integration of a threedimensional digital graphic model of the quantitative and qualitative information of the objects that comprise it, the relationships that may be established among them, and their links to external documents. This characteristic offers high potential as a heritage information system that has already generated numerous research papers (Logothetis, 2015). The use of heritage BIM is presented in academic publications under different Abbreviations: AEC, Architecture Engineering &Construction; BIM, Building Information Modelling; HBIM, Heritage Building Information Modelling; IAPH, Instituto Andaluz de Patrimonio Hist orico (Andalusian Institute of Historical Heritage); LOD, Level of Development; LOK, Level of Knowledge; MECD, Ministerio de Educaci on Cultura y Deporte (Ministry of Education Culture and Sport of the Government of Spain). * Corresponding author. E-mail address: [email protected] (M. Castellano-Rom an). Contents lists available at ScienceDirect Digital Applications in Archaeology and Cultural Heritage journal homepage: www.elsevier.com/locate/daach https://doi.org/10.1016/j.daach.2019.e00110 Received 17 May 2019; Accepted 8 August 2019 2212-0548/©2019 Elsevier Ltd. All rights reserved. Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx Please cite this article as: Castellano-Rom an, M., Pinto-Puerto, F., Dimensions and Levels of Knowledge in Heritage Building Information Modelling, HBIM: The model of the Charterhouse of Jerez (C adiz, Spain), Digital Applications in Archaeology and Cultural Heritage, https://doi.org/10.1016/ j.daach.2019.e00110 denominations and corresponding acronyms. The most widespread use is Heritage Building Information Modelling, HBIM, which has been applied in this research. However, published cases are very different in terms of their scope and purpose, without a specified general conceptual framework in which to define each case study (Danae Phaedra Pocobelli et al., 2018). Therefore, the main objective of this research has been to characterize HBIM as a methodology for the comprehensive management of cultural heritage, including in this concept the activities of research, protection, conservation and dissemination in its broadest sense. In parallel, to characterize HBIM as a particular case of BIM when it includes a building of cultural value as a specific object, so that the processes are compatible in situations where the activities carried out on the cultural asset overlap with activities carried out on a new site. For this purpose, this research aims to offer an interpretation of the Dimensions and Levels of Development in HBIM, compatible with corresponding BIM definitions and to demonstrate its application in a specific case study: an HBIM model of the Charterhouse de Nuestra Se~ nora de la Defensi on in Jerez de la Frontera, also known as Charterhouse of Jerez, focused on strategic planning of heritage management at the Master Plan level (Fig. 1). 2. Different focuses of HBIM Under the title HBIM, three groups of experiences have been recognized, however, they differ profoundly in terms of objectives, methodologies, and results. The first is that which deals with the modelling of historical buildings as a particular case of the modelling of complex geometries associated with parametric design. In this case, the model must necessarily be based on an existing building or some of its conserved parts. However, it may be modelled through theoretical definitions or ideal models. Elements of classical orders, for example, may be the subject of complex parametrization for its application in different historical models (Aubin, 2013). Its most direct application is the generation of HBIM models of virtual reconstructions of monuments that no longer exist, which relates them, above all, to activities of research and dissemination of heritage management. This places this line of work within the context of the techniques of virtual reconstruction and visualization of historic buildings, whose reference document is the so-called Principles of Seville (L opez-Menchero and Grande, 2011), based on its direct precedent, the London Charter (Bentkowska-Kafel et al., 2012). A second group of experiences has as its main objective the generation of HBIM models with high geometric accuracy as a result of the manual or semi-automatic processing of point clouds based on digital photogrammetric captures or 3D scans of existing buildings (Barazzetti, 2016)(Tommasi et al., 2016). The main methodological issue focuses on the capture of formal attributes of the building and its transformation into parametric objects typical of BIM modelling (Brusaporci, 2015). This reaffirms the interest in the issue of geometric accuracy of models in BIM among the authors analysed (Garagnani and Manferdini, 2013). In this approach, the HBIM model would necessarily be linked to a maximum geometric accuracy, and this requirement must be verified from the early moments of the modelling process. Therefore, the possibilities of progressive refinement of HBIM models through levels of development or the modelling of missing structures corresponding to other historical phases of the building are not explored. Third, a group of experiences is recognized in which the main objective of the model is the analysis and generation of knowledge regarding the building itself. Digital capture technologies happen to be secondary, although not necessarily relegated. It is not only about digital capture and transformation into an HBIM model, but rather it is part of an architectural survey process, in the sense that it is defined in the Carta del Rilievo, in which it expressly indicates that “the critical path of the constructive process, and also the project must be verified”(Jim enez Martín and Pinto Puerto, 2003). Therefore, the technology applied in the graphic construction associated with the survey does not determine it a priori, but simply characterizes it against other methodological options. Thus, in this HBIM approach, the priority is not the achievement of high accuracy three-dimensional modelling, but the exploration of BIM possibilities in architectural survey, as a form of heritage building knowledge. Geometric accuracy is a characteristic of the model that may evolve according to its level of knowledge and development. The research presented is framed within the latter group, focusing on the possibilities of HBIM in the comprehensive management of the Fig. 1. Charterhouse of Jerez. Church atrium. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 2 heritage building of cultural value, starting with the knowledge generated by the research, progressing through activities of protection, conservation, intervention and completing with dissemination. In this sense, a case that is relevant for this research is the Aqueduct of Aguas Libres in Lisbon (Rua and Gil, 2014). This work proposes a methodological option that postpones the acquisition of maximum geometric accuracy, which can be accessed later, for the sake of an integral approach to the heritage asset as a whole that addressed the urgency for its evaluation in order to prevent loss. Another case with similar conceptual foundations is that developed in the Italica Archaeological Site, where the site is treated in its entirety by establishing an active cartographic base (Pinto et al., 2011) for the systematization of heritage information of the complex, using BIM systems for the management of diagnosis and conservation (Pinto et al., 2010). From an initial basic definition, but which covers the entire complex, the response to the requirements proposed for its Master Plan are addressed. Subsequently, progress is made in the level of development of a defined area, with a specific project for the Casa de Hylas, in which photogrammetric accuracy was achieved (Angulo Fornos, 2009). Specific areas of heritage management are developed in other case studies, like digital anastylosis (Angulo et al., 2017), monitoring and simulation data (D. P. Pocobelli et al., 2018) or interventions (Jordan-- Palomar et al., 2018). Finally, the case of the Church of San Pedro de Arcos de la Frontera (Castellano Rom an, 2013), in which the generation of the model and the information structure linked to it were focused on research and legal protection through registration as an Asset of Cultural Interest. 3. Case study The asset selected for study is the Charterhouse of Nuestra Se~ nora de la Defensi on in Jerez de la Frontera, a monastery located 5 km from the urban centre, occupying a confined area between the Jerez expressway to Medina Sidonia and the Guadalete River (Fig. 2). Its architectural configuration is articulated around the monastic nucleus, which is surrounded by different structures of different origins and functions, which result from its long historical process. The foundation was constructed in the 15th century and its constructive evolution develops throughout the 16th and 17th centuries until the end of the 18th century. During the 19th and 20th centuries, the Charterhouse of Jerez experienced ruin, plunder and neglect with respect to its cultural value, protection and conservation. The result of these historical upheavals is the Asset of Cultural Interest that survives today and in which, far from resolution of the confrontation between loss and conservation of its heritage value, gaps remain in management, unworthy of its heritage value and in the state of knowledge that the disciplines concerned in terms of cultural heritage have reached, seriously threatening its survival. The selection of the Charterhouse of Jerez as a case study is relevant for several reasons. First, due to the heritage value of the monument, the repository of uncontested values due to their antiquity, historical significance, and artistic, archaeological, architectural and territorial relevance. The second reason is the existence of a large amount of heterogeneous documentation of diverse origin, which is an excellent basis to prove the usefulness of the proposed heritage information model. It contains historical documents, photographic collections, historical iconography, planimetry, intervention projects, journalistic reviews that have not yet been systematized in the interest of a global and synthetic interpretation of the monument. Third, is the multiple scales of approach to the whole, which goes from the territorial to the objectual. The interpretation of the Charterhouse of Jerez goes beyond the strict delimitation of its monumental area. In fact, one of the characteristics that defines the Charterhouse foundations as a typological category is its peri-urban location. This position provides a territorial and landscape dimension, which in the case of the Charterhouse of Jerez is associated with its relationship with the main nucleus of the city, the fertile plain of the Guadalete River, and a historic infrastructure of great importance such as the Charterhouse Bridge and to the exploitation of the surrounding rural environment, in which it was a principal actor whose imprint can still be read on the territory. The architectural scale offers the volumetric, spatial, functional and Fig. 2. Charterhouse of Jerez. Second half of the 20th century aerial photography. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 3 symbolic richness of a monastic structure, offering great potential for analysis through HBIM. The complexity of this structure will be superposed by the vicissitudes of the works that took place during monastic life and, above all, the recovery repairs after the abandonment and plunder resulting from the exclaustration of 1835. This scale also offers all types of situations worthy of registration in the heritage information model, from the characterization of its conservation status to the quantification and assessment of the urgency of repairs. But this scale not only addresses the material reality of the monument, but also offers the possibility of registering the information related to the movable heritage that it contains, with overflowing richness. Finally, there is another reason for the selection of the Charterhouse of Jerez as a case study: the complexity of its management. Its declaration as a National Monument in the 19th century meant, once the Law of Spanish Historical Heritage, LPHE, was enacted, its automatic assimilation to the figure of Asset of Cultural Interest, BIC. Although direct transition from one figure to another seems fully justified, not all the consequences of this automatic process are positive. The figure of BIC within the LPHE and its subsequent development in the different regional regulations incorporate, both in the administrative process and in its legal consequences, a much broader consideration of heritage values than that derived from the declaration as a National Monument in the 19th century. Consequently, the Charterhouse of Jerez lacks a precise and generous delimitation that clarifies the structures included in the BIC figure, which has made possible, very recently, interventions that have supposed irreversible losses. Likewise, it lacks the delimitation of a protection environment accompanied by a declaration as BIC, which prevents establishment of heritage value of the Charterhouse in an immediate environment full of natural and built structures, without whose consideration, it is impossible to interpret the meaning of the monument. Finally, the high complexity that this monumental group offers, from all perspectives of heritage management, guarantees that the conclusions of the case study are, to a great extent, extrapolated to other building assets of cultural value. 4. Methodology The methodological actions for the generation of an HBIM model of the Charterhouse of Jerez focused on the strategic planning of its heritage management have been developed in four superposed levels, whose continuous interactions have served to enrich its content. In the foreground has been the review of documentary sources, in any format, in order to constitute the most exhaustive repository of information possible to obtain the necessary data. The second level has been the consideration of the monument itself as a document, attempting to record the material traces that prove or refute, as applicable, the data provided by the documents. The third level has been that of architectural analysis, focused on the interpretation of the design, layout and construction processes as well as on the conception of the architectural space that these reveal. The fourth level has been the generation of a model in which, due to the specificities of BIM methodology, tests the diachronic configuration sequence of heritage reality that exists today as Charterhouse of Jerez. A Heritage Building Information Repository, HBIR, of the Charterhouse of Jerez has been created, hosting the numerous and heterogeneous existing documentary records regarding the monastery. Its structure has been designed according to this fundamental characteristics: the centralization of information, an integrating perspective of all areas of heritage management, the purpose of exhaustive compilation of existing information resources and digital medium. The digital nature of the HBIR is framed within the scope of new information technologies and has required a strategy for digitalization of non-digital information resources. The proposed structure is characterized by attempting to provide an integral response to possible management actions so that, in accordance with the declared objective of exhaustiveness of the HBIR, any information resource related to the asset may be accommodated. Therefore, they are structured according to a sequence of directories whose denomination responds to the main lines of action for heritage management: Identification, Protection, Conservation, Dissemination and Research. To these is added the Source Management directory. The evolution of the registry will, therefore, be developed cumulatively, by continuous addition of documents and references produced by the different agents involved with the asset (Fig. 3). The review of information sources has been complemented with field studies consisting of a series of visits to the Charterhouse and its territorial environment, in which direct data has been collected and which has verified or refuted the data provided by the documents. Only direct observation has been used. And, even with this limitation, it has been possible to recognize material evidence of structures reflected in historical documents that no longer exist. Possible archaeological contributions in this area would have been decisive, but its opportunity would have to be linked to future interventions covered in the strategic planning required by the Charterhouse of Jerez. Documentary records of these field studies, produced in the form of photographic collections and drawings, have been incorporated into the documentary repository, for use in this research, as well as any that may be developed in the future. Historical data has been structured in an Access©database in which each record has been linked to the spatial location within the building. With this information, a timeline has been generated that has enabled characterization of the constructive evolution of the monastery and to manage the time dimension of HBIM modelling (Fig. 4). Generation of the model has been carried out using Autodesk Revit® 2017. Modelling has been carried out in parallel to the analysis, given that both processes are interrelated: the analysis offers keys to generate the model and the modelling process reveals unapparent relationships that enable a new reading of the information sources used during the analysis (Fig. 5). In turn, for the construction of the model, two interdependent lines of work are addressed. On the one hand is the definition of the information parameters, establishing knowledge categories as broad as necessary to register all its heritage complexity and, simultaneously, sufficiently specific for viable use as an information system. On the other hand is the design of a digital graphic model with the capacity to integrate these knowledge categories and to mediate between the information and the user that requires it. The process carried out has enabled definition of a content proposal for HBIM Dimensions and for the levels of HBIM development, named as Levels of Knowledge LOK. Fig. 3. Structure of the Heritage Building Information Repository. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 4 5. Dimensions in HBIM At this point, a definition of HBIM may be synthesized, based on the previous considerations. This definition has been constructed so that HBIM is understood as an extension of BIM for built cultural assets, seeking the conceptual and methodological parallels that ensure its compatibility. Thus, HBIM may be defined as an interdisciplinary work methodology for sustainable management of built cultural assets. Its objective is to coordinate and articulate all the information of the cultural asset in a digital information model from which all management agents may participate. The model may incorporate analytical survey (3D), historical evolution (4D), diagnosis (5D), cultural context (6D) and conservation and intervention (7D). HBIM transcends the mere geometric characterization of the heritage asset and offers an effective instrument for sustainable management (Fig. 6). In HBIM, geometric 3D information is associated with the survey and analysis of the heritage asset. In this process, the assistance of advanced accuracy surveying technologies, such as photogrammetry or three- Fig. 4. Timeline characterization of the constructive evolution of the Charterhouse of Jerez. Fig. 5. Geometric analysis of the Charterhouse of Jerez. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 5 dimensional scanning, may be required, but it is not absolutely essential. In fact, it is considered that the HBIM model requires, above all, an “accurate”architectural analysis in the sense that the definition of a coherent modelling strategy with the heritage keys of the asset is much more decisive in the construction of an HBIM model than the level of accuracy achieved in its metric and geometric characterization. A highresolution point cloud, or automatically generated model, may offer a true picture of reality, but not necessarily a high level of heritage knowledge. If the time factor of a 4D BIM model is fundamental for the control of the construction process and maintenance of the building, in HBIM, it acquires transcendental relevance as it is this characteristic that enables recording of the time evolution of the cultural asset, becoming a fundamental instrument for its diachronic interpretation. In the HBIM model, the phases may present the main stages of the construction process of the asset, with the overlapping processes of construction and destruction that result in its recognition as heritage. From the moment of the constitution of the HBIM, new phases may be incorporated that reflect the different affecting management actions. In HBIM, we cannot talk about construction costs properly, 5D BIM, since obviously the heritage building is already built. Thus, the transfer of this aspect from BIM to HBIM is not direct. However, a parallelism may be established between the estimation of construction process costs for a new building with the estimated cost of the intervention process for heritage assets. Costs are mainly associated with the construction systems selected to solve a certain design in the construction of a new building. For the intervention of the heritage assets, costs will be associated with the constructive solutions selected to solve a certain diagnosis of the asset. This diagnosis should not be understood only in terms of identification and characterization of structural damage, but rather from an integral management perspective: aspects related to achieving better knowledge of the asset, establishing adequate legal protection, preserving its materiality, and promoting the dissemination of its values to society. Attention to the environmental dimension attributed to 6D BIM implies incorporation into the model of aspects that go beyond consideration of the building as an isolated object, taking into account the interaction with the environment in which it is inserted: its sunlight, its energy balances, and the impact of the construction process itself. These considerations are perfectly transferable to the HBIM model since, although their fundamental constructive systems would already be configured, the environmental conditions would determine, to a great extent, the keys of material conservation. However, in HBIM the environmental reference cannot be limited only to the consideration of the natural environment but must be extended to its cultural contextualization. The 6D content of the HBIM involves addressing the interactions of the asset with its physical and cultural environment in aspects such as the historical evolution of its basic infrastructures of supply and transport, obtaining the economic and material resources for its construction, and its transformative effect on the territory. BIM incorporates 7D information to address the building maintenance. Transfer to HBIM is direct, since maintenance may be associated with preventive conservation, whose purpose is the preservation of the cultural values of the heritage asset. But, again, when referring to 7D in HBIM, not only the preservation and intervention on the property must be addressed, but also the programming of research, protection and dissemination of its values. Finally, BIM addresses optimal management, particularly in terms of cost of the entire life cycle of the building, which inexorably concludes in the demolition thereof at the end of its useful life. For HBIM, this optimal management is considered as sustainable management, meaning and strategically planned actions to achieve the best knowledge, protection, conservation and dissemination of the asset with the least economic impact on those responsible for its management. Even more relevant is the sustainability of this management when, unlike BIM, HBIM does not include the end of the useful life of the property, given the objective of indefinite preservation. 6. Levels of Knowledge LOK in HBIM The transfer of the Level of Development LOD concept to HBIM cannot be carried out in terms of the evolution of the project and construction of the building, since it already exists, but it must refer to its Level of Knowledge and the heritage management to which this Level of Knowledge can provide sufficient information. Thus, when referring to LOD in HBIM, it would be more accurate to refer to the Level of Knowledge, LOK, since this term suggests, in line with contemporary theories of heritage intervention, the need for deep knowledge of the cultural asset prior to carrying out any action. The relationship between the Level of Knowledge LOK and level of detail, understood as graphical accuracy of the survey, is not direct. Unquestionably, the graphical accurate survey, a high-resolution threedimensional scan, for example, constitutes a great contribution of information regarding the object of study. However, it would be practically only that: a lot of indiscriminate information waiting to be processed for the generation of information categorized and classified ready to be significant in heritage management. Therefore, the Levels of Knowledge proposed from this research address the type of heritage management that may be carried out based on available information. And, it is evident that a conservation project for a cultural asset requires, among other information, an accurate graphical survey. However, it is equally evident that with a graphical accurate survey as a source of exclusive information, it would be difficult to progress in terms of conservation or intervention. For the categorization of the Levels of Knowledge, five levels are proposed: LOK100, LOK200, LOK300, LOK400 and LOK500, a denomination intentionally parallel to that used in BIM methodology with the aim of simplifying the conceptual repertoire generated around it (Fig. 7). Level of Knowledge LOK100 is associated with the identification of the heritage asset and its basic characterization. The level of graphic accuracy achieved at this time is not fundamental, since a symbolic code such as a mark or simple volume would be objects capable of identifying the asset and its basic characterization, including, of course, georeferenced location and orientation. At this point, it would be possible to Fig. 6. Dimensions in HBIM M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 6 propose a convergence on Geographic Information Systems and its graphic and information strategies, in which, due to its large scale, assets becomes characterized in this symbolic way. But also a point cloud, resulting from a three-dimensional scan or photogrammetric capture, may be included in a LOK100 as a single object capable of containing basic identification information, as long as graphic codification is not categorized. Level of Knowledge LOK200 enables graphic characterization and sufficient information for the development of actions related to legal protection of the asset and its strategic planning or Master Plan. The graphic model must contain its basic structures: walls, floors, roofs, as well as sufficient information to justify the heritage valuation to receive the level of protection attributed to it, and it has to provide graphical support for dissemination. At this point, a documentary repository linked to the model in which the documentary sources are recorded should be created and digitized from the various formats in which they are presented, or, if this is not possible, a simple reference to their location. This structure, which is parallel to the model, has been defined as a Heritage Building Information Repository, HBIR when the research methodology was presented. Level of Knowledge LOK300 goes deeper in the characterization of graphic entities to the point of being able to show the results of specialized research carried out using archaeological methodology or other specific disciplinary studies of monitoring and diagnosis. This would be an advanced model of knowledge of the asset in a position to undertake the next level, LOK400, which would include specific conservation and intervention actions on the elements of the asset. That requires specific information regarding the criteria and procedures employed. Finally, LOK500 deals with HBIM models used for efficient management, systematically registering the different actions planned. One of the hypotheses raised in this research is that it is possible to approach sustainable management of a monument of the scale and complexity of the Charterhouse of Jerez using BIM methodology. The goal of producing an HBIM model of the Charterhouse that corroborates this hypothesis introduces one of the main features of this methodology, the possibility of progressive enrichment of the model managed through the aforementioned Levels of Knowledge. In the research presented, LOK200 is established as the foundational level of the Charterhouse of Jerez HBIM, meaning, a level that enables laying the groundwork for the Master Plan of the Charterhouse of Jerez. The graphic and information features shall be specified in later sections, but it is necessary to establish two considerations in this point. First, that the Charterhouse of Jerez HBIM is based directly on LOK200, without previously going through the LOK100. It has to be taken into account that the Charterhouse of Jerez was recognized as National Monument in 1856, so there is no need for its identification as an integral part of Spanish historical heritage. LOK100 would be relevant for other cultural assets lacking heritage recognition, in order to promote its legal protection. Second, that LOK in HBIM need not be developed in a synchronized way for all the elements of the model. In fact, this constitutes one of the main advantages of its heritage application. Deeper knowledge of the parts of an asset may not be homogeneous. The opportunity of certain interventions or research will increase the knowledge of some parts at the expense of others. Even more so in a case such as the Charterhouse of Jerez, whose breadth and complexity have hindered its comprehensive interpretation. Therefore, even when LOK200 is established generically for the Charterhouse HBIM model, progress has been made towards LOK300 in some areas of the model as a way to probe the possibilities of advancing research in this regard. The areas in which progress has been made in this direction have been the entryway of the church and the north-eastern corner of the Great Cloister. 7. HBIM model of the Charterhouse of Jerez According to this conceptual proposal, the HBIM model of the Charterhouse of Jerez has been generated, considering the information required for strategic planning of the main areas of action for heritage management: research, protection, conservation and dissemination, known as the Master Plan. This purpose of the model corresponds to Level of Knowledge LOK200, as explained in the previous section. 7.1. Geometric definition of the model The construction of the graphic model is inseparable from the process Fig. 7. Characterization scheme of the Levels of Knowledge LOK in HBIM. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 7 of knowledge of the asset that is modelled. As described, when presenting the methodological questions of this research, these are parallel and interrelated processes. This fundamental characteristic distinguishes the graphic model produced from any other three-dimensional graphic modelling of the heritage. The analysis has provided the keys to establish the zoning of the model, the modelling strategy, or the establishment of the phases, which will be explained as the decisions made in the construction of the HBIM model are described. In this case, the construction of the model is not based on a digital capture using photogrammetry or digital scanning of the entire monastery. That is precisely one of the singularities of this case study: the model is based on the information available at the beginning of the research without the need for initial investment in extensive metric capture in order to evolve towards higher levels of LOK, as defined. There were two partial photogrammetry surveys, corresponding to the two main gates, a 2D CAD survey, 3D CAD surveys, analogue surveys, historical graphic sources and current photographs. All of these are registered in the digital Heritage Building Information Repository, HBIR. This means that the HBIM model has required the integration of diverse graphic sources to build a model of great extension and different levels of geometric accuracy, but that satisfies the Level of Knowledge LOK200 required for the Master Plan of the monastery (Fig. 8). 7.2. Central Project and Linked Projects Precisely due to the large area of the Charterhouse of Jerez, the first decision related to the construction of the model is that which arises when assessing whether the HBIM model will be developed as a single project or as a series of projects linked to a central project. In this sense, recognition of the Charterhouse of Jerez as a complex asset, composed of different structures with different levels of articulation, has justified the transition of that complexity to the configuration of the HBIM model and the option for a central project with a series of linked projects. The delimitation of the linked projects responds to the zoning resulting from the analysis of the whole, enabling differentiated areas with their own development, both in terms of LOK and management of future partial projects of the complex. A key criterion when defining linked projects has been the identification of an exempt building or one with a high degree of autonomy, generally derived from a constructive impulse clearly defined in time. Another criterion has been the recognition of a group of structures with a singular spatial-functional concept within the complex. Likewise, the criterion of historical contemporaneity of certain structures has also been applied. Each differentiated project may have a diachronic development, due to the priorities established in the master plan, but always linked to the central project that constitutes the HBIM model of the entire monumental complex (Fig. 9). 7.3. Historical evolution modelling As in other aspects of the software, a utility thereof, not specifically designed for the cultural heritage building, is easily adaptable and offered as a valuable tool for analysis in HBIM. In this sense, the “phases” have been revealed as one of the most valuable tools, enabling modelling of the historical evolution of the Charterhouse of Jerez. The association of phases to historical stages in HBIM has meant, in practice, the work of several simultaneous models that correspond to each characterized phase (Fig. 10). In an initial approach, the phases of the model could be constituted as a chronology, matching each piece dating with a phase of the model. Given that hundreds of dates have been recorded, associated with constructive events, a model of hundreds of phases would be considered, but that would be absolutely inoperable. This need not always be the Fig. 8. Geometric definition in the Charterhouse of Jerez HBIM. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 8 case, given that certain cultural assets, with less architectural complexity and narrower time margins of constructive evolution than the Charterhouse of Jerez, could make it viable. Discarding this option would offer the possibility of establishing phases associated with regular time ranges, such as centuries or decades or objective historical periods depending on a relevant parameter, such as the sequence of monarchs. However, this option was not consistent with the objectives and methodology of this research, since it did not place the knowledge of the asset as the key for methodological decisions. Therefore, it has been decided to establish a sequence of phases that describe periods of very different durations, from just a few years to more than a century, but whose beginning or end are associated with significant events of the building’s own evolution. The phases are differentiated by their correlative numbering and by a denomination that refers the works or the most relevant event of that period. The use of phases does not exhaust the 4D development of the HBIM model. In fact, the constitution of the Access database to which reference has been made in the methodology, includes date parameters that may be associated with the different locations of the model or, in higher Levels of Knowledge to the different objects comprising the model. 7.4. Structures and spaces modelling Once the projects are configured and georeferenced, the modelling process begins, for which the parametric objects offered by the program have been used: Topographic Surfaces, Conceptual Mass, System Families, and Insertion Families. Each has been used due to its adaptation to the structure to model and always, as a fundamental criterion, seeking optimum adaptation to the role that the architectural analysis has assigned it. “System Families”includes all the parametric objects that enable modelling of basic building structures: walls, floors, roofs, structural elements and others. These objects have been programmed with advanced editing options that enable characterization of an unlimited number of contemporary constructive solutions as well as an equally unlimited selection of graphic solutions for viewing. Its use in BIM, following the process of progressive increase of the Level of Development, is in the conceptual design through masses enabling, initially, generic definition and in later phases, complete geometric and information definition. In the Charterhouse of Jerez HBIM, these families have been used extensively to model the vertical or horizontal structures whose constructive configurations are known through contemporary planimetric sources and those that, although totally or partially no longer exist, may be virtually rebuilt with sufficient reliability. Thus, all the structures currently existing in the Charterhouse of Jerez have been modelled with these families using generic types with the capacity to be developed constructively using deeper knowledge. Among these System Families, a type of fundamental object in BIM must be considered. These are rooms, a somewhat prosaic name that evokes spaces with limited spatial qualifications, but which, in the end, enable modelling of not only the constructive elements, but also the spaces confined by them, materially or conceptually. The assortment of objects is completed with the “Insertion Families”, parametric objects that may be modelled independently of the projects. In fact, these even have a specific graphic editor and are inserted into projects freely. In general, their role in BIM is associated with all constructive elements linked to industrialized production and, which therefore, may be used as an object library for the development of projects. However, in addition, the generous flexibility offered by the geometric and information modelling addresses unique design elements modelling. And this is the utility for direct transition to HBIM, given that it enables modelling of the elements of the heritage building whose formal singularity requires complex modelling, not possible with System Families. In the Charterhouse of Jerez HBIM, they have been used for the modelling of the main and church gates, the cloister and church gallery vaults, and others of similar complexity. Fig. 9. Central project and linked projects in the Charterhouse of Jerez HBIM. M. Castellano-Rom an, F. Pinto-Puerto Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx 9