The virtual model in HBIM

The analytical processes and the creation of 3D models have different connotations depending on the intended end result, which may be, for example, the virtual reconstruction of historic buildings. As a result of the development of a 3D model and 2D plans, both strictly construction information and non-dimensional information, such as conservation sources, can be linked.

Modelling in the CAD environment for contemporary BIM objects is based on the use of semantically recognisable objects that are enriched with various types of information (materials, technical features, costs, time phases, etc.).

The modelling of historic buildings duplicates the initial phase of modelling in a CAD environment for contemporary designed objects. However, only after the actual modelling of individual unique elements that do not exist in the resources of digital tools, such as vaults, windows, doors, columns, lintels, for example, can they be supplemented with material, historical and conservation information. This study fully reproduces the model with the highest level of detail – we are then dealing with an HBIM model.

With the above in mind, in order to obtain information on the topology and semantic characteristics of architectural objects, it is necessary to produce other types of models that are not strictly typical of the prefabrication phenomenon. In the case of the creation of objects in the HBIM environment, we are dealing with a reverse engineering operation, in which the reading and segmentation of the point cloud, once the characteristic areas have been identified, is the first step to identify the surface boundaries that facilitate modelling, the end result of which is to build a digital virtual model of the architectural monument in HBIM technology for further Historical Building Information Modelling, allowing continuous and immediate access to information about the project, its costs and maintenance schedules.

The innovation of this inventory method lies in the fact that it enables the direct creation of virtual building elements (HBIM model), in which, in addition to the three-dimensional representation and standard projections, additional information will be included (e.g. assignment of technical or conservation details). This will translate into a greater ability to assess both the condition of the building and possible conservation measures. Simultaneously with the measurement, a virtual model is built, observed on the computer screen in the form of an axonometric or perspective view, freely guided projections, sections or elevations.

Inventory and documentation development using HBIM technology allows for the creation of a complete database of the historic building and consistent documentation. Thanks to the great precision of the space reproduction, we will obtain a fully automated process, available in real time for the creation of countless sections, elevations or projections, which will undoubtedly open up new possibilities for research, comparison and analysis of solids and details.

The HBIM model obtained as part of the inventory, thanks to the use of specialised software, will be useful for a variety of applications, such as the precise planning of conservation work, the incorporation of new elements, the completion or restoration of missing elements (reverse engineering) and the creation of a virtual historical reconstruction. It will also be possible to obtain a strength model of the existing building taking into account possible new design measures, as well as determining the energy performance of the building.

Another very important aspect of using such a model is the possibility of making a qualitative and aesthetic assessment of the intended restoration and architectural works before their actual implementation on the finished model, which is tangibly accessible to the viewer by means of VR technology (virtual reality). Another application is the design of illuminations, colour variants and finishes for the building, or greenery and landscaping elements in relation to the architectural monument that is the subject of the study.