From Reality to Parametric Models of Cultural Heritage Assets for Hbim

Abstract

<p><strong>Abstract.</strong> The ability of managing big amounts of metric information coming from a LiDAR survey and the ability to reproduce high quality 3D models from them are still vivid problems to solve. Is it possible to create detailed models, geometrically and metrically correct, without using a large amount (often redundant) of metric data, such as massive point clouds? Obviously yes, but there are several ways to create a fitting 3D model for a specific research. A good solution is given by NURBS based algorithms that ensure high details of modelling. However, NURBS models can't be used directly on BIM platforms, because they need to be parametrized. In this sense, a parametric model is based on real measurements but each object could be interpreted and approximated based on objective and subjective (critic) view and also based on LODs (levels of detail or development) concerning a particular analysis. This kind of modelling of Cultural Heritage assets, fundamental for HBIM creation, need to be correctly planned especially for classification and definition of its historical features connected to an informative system, because nowadays information and then the semantic dimension are a necessary key points towards documentation analysis.</p> <p>Established this brief introduction, this schematic work will focus on the analysis of FreeCAD open BIM software and Rhinoceros as NURBS 3D modeller for Cultural Heritage is concerned, and whether and how they could integrate their tools for the purpose of managing dynamic high detailed data for the creation of an HBIM platform.</p>

HBIM, 3D drawing and virtual reality for archaeological sites and ancient ruins

“…Therefore, in-depth knowledge of the artefact requires the application of a generative method capable of faithfully representing each type of object from the largest to the smallest, thus becoming a useful analysis tool for archaeologists and restorers. For this research, in light of the requests of professionals, the need to further increase the LOD and LOI connected to the virtual model has grown, following the path traced by previous studies in this particular field of application (Chiabrando et al, 2017;Garagnani et al, 2016;Diara & Rinaudo, 2019;López et al, 2018;Parrinello et al, 2017;Rossi, 2019;Scianna et al, 2014;Stampouloglou et al, 2019). Furthermore, in Banfi et al, 2019, they have been defined as the main steps of a digital workflow applied for quality management and quality assessment of HBIM and VR projects for heritage buildings.…”

Building Archaeology Documentation and Analysis Through Open Source Hbim Solutions via Nurbs Modelling

“…This decision has been taken especially since actual BIM platforms, including open source solutions as FreeCAD, are affected by modelling limitations, based essentially on predefined libraries of theoretical architectural elements as well as the simplified parametric modelling starting from geometric primitives composing main volumes of architectural elements. So, this modelling choice can be adapted for the refectory as well as Cultural Heritage assets purposes, because their features and peculiarities can be hardly represented by using predefined libraries (Adami et al, 2017;Diara et al, 2019;Giannattasio et al, 2019). However, NURBS surfaces and objects aren't parametric models and for this reason they cannot be directly implemented inside a BIM platform, but, as we will see, there are different solutions for the purpose of parametrize NURBS models (Oreni et al, 2014;Diara et al, 2019), allowing to modify construction parameters of 3D objects, according to BIM modelling purposes.…”

“…The willingness to test and observe how a BIM solution can adapt its workflow to Cultural Heritage assets brings this project towards new possibilities resulted from FOSS (free and open source) solutions, trying to understand how open BIM software is convenient for the purpose of creating a full operative HBIM platform for buildings archaeology purposes (Logothetis et al, 2017;Diara et al, 2018;Beltramo et a., 2019;Diara et al, 2019). In this sense, FreeCAD software has been used and fully exploited for this project.…”

“…The refectory NURBS model has been subsampled (depending on architectural elements) and exported by using STEP format (Standard for the Exchange of Product model data). Then, NURBS shapes and surfaces are objects unusable inside a BIM environment because they are without the editable volumetric and thickness parameters and for this reason needs to be managed manually in order to become parametric objects (Oreni et al, 2014;Banfi F., 2017;Diara et al, 2019). This procedure has been managed by using different FreeCAD workbenches: Defeaturing workbench has been used in order to remove original features of NURBS objects obtaining optimized surfaces ready to be extruded; the default Part workbench has been adopted for the purpose of using the extrusion command tool for the resulted surfaces, obtaining in this way editable volumetric and thickness parameters; DynamicData workbench has been helpful for the creation of Python "containers" for managing and customizing features, properties and metric data in real time, also using the internal database.…”

An historical building information modelling approach for the preventive conservation of historical constructions: Application to the Historical Library of Salamanca

“…As stated by Diara and Rinaudo (2019) [18], HBIM models extend the possibilities of CAD models by adding semantic relations between the 3D objects and information. This relation could be understood as the LoI of the object, demanding the proper definition of materials or degradation processes among others.…”