of development and urban planning that responds to the many challenges of competitiveness, social cohesion, preservation of resources and sustainable development and innovation requires the development of concepts and new approaches to planning and a better integration of opportunities offered by new 3D technologies. The integration of 3D GIS and BIM allows the study of the dynamic relationship between physical and environmental conditions, urban geometry and the properties of each building. Such integration will help achieve smart, resilient and sustainable urban spaces (Niu et al. 2015). Having multi-scale urban models not only helps to meet the current requirements for urban space analysis and management, but also helps meet the future and prospective needs of tomorrow’s cities.
However, there are several conceptual and technical complexities that arise from BIM-3D GIS integration. This is mainly due to dissimilarities between the two domains in terms of spatial scale, level of granularity and detail (LoD), geometry representation methods, storage and access, and semantic dissimilarities. There are three main levels of 3D BIM-GIS integration: data-level integration, application-level integration and model-level integration. This last level is more flexible until one of the two models (BIM or 3D GIS) is extended through its standard to integrate the data and elements of the other model. Another more advanced level of extension is the development of a meta-model that mediates between the two models at a higher conceptual level. In the literature, the contributions in the integration of BIM and 3D GIS are notable, but are far from being able to solve all the technical problems inherent to this integration (Biljecki and Tauscher 2019). This is a niche area of research that is still active.
Interoperability: a major challenge for multi-scale BIM
In the general context of “Data Sciences”, the exchange and sharing of data is unavoidable. Given the heterogeneity of systems, tools and formats, interoperability is recognized as a major challenge in the integration of multi-source data. Interoperability is the ability to ensure that data generated by one user can be correctly interpreted by all other users (Shen et al. 2010). Data interoperability enables reliable and efficient information exchange: it is a prerequisite for effective system integration in a collaborative context. The goal is to eliminate or reduce time-consuming and error-prone manual interventions inherent in the operation or exchange of data between software and users.
Interoperability in 3D urban modeling is the fundamental objective behind the development of the CityGML standard. CityGML is an open data model for the storage and exchange of 3D city models. The objective of the development of CityGML is to achieve a common definition of the basic entities, attributes and relationships of a 3D city model. CityGML is based on a very rich geometric, topological and semantic data model. It also provides a multi-scale representation through a number of defined levels of detail for urban objects (Gröger et al. 2012). The most commonly used level of detail is that of buildings.
In the field of construction engineering, IFC (Industry Foundation Classes) has been proposed as a standard based on an open object-oriented model. IFC is designed to model the objects of a BIM in terms of geometric information, semantics and relationships between elements to facilitate the interdisciplinary coordination of BIMs, the sharing and exchange of data between IFC-compliant applications, and the transfer and reuse of data in different contexts.
Over the last few years, a number of studies have been conducted to examine the potential for the integration of GIS and BIM (GeoBIM) through the standardization of exchanges between IFC and CityGML. However, the technical issues inherent to the management of interoperability between the two schemas are far from being mastered and still mobilize several research groups such as the EuroSDR GeoBIM working group (Noardo et al. 2020).
Scientific contribution to this book
This book deals with important issues around the concept of “multi-scale BIM” from the perspective of intelligent and sustainable urban management. Its main contribution lies in appreciating the potential of multi-scale BIM in the development of a real territorial strategy, allowing professionals and researchers to place territorial data in contexts of analysis and interpretation in order to provide integrated urban knowledge for intelligent territorial management. The concepts treated and the practical use cases presented in this book will provide essential building blocks for the development and implementation of smart cities. The book enables:
– reviewing the state of the art in terms of technologies, methods and approaches to implement a multi-scale BIM;
– addressing the conceptual and technical aspects around the interoperability of BIM and 3D GIS models and their integration under the GeoBIM concept;
– helping professionals in the field of geospatial sciences, architecture and construction to share a common vision of BIM and CIM (City Information Modeling) and to understand their integration;
– presenting three practical case studies illustrating concrete examples of multi-scale BIM implementation.
Book structure
In order to pose the problem in a structured way, this book is divided into eight chapters:
Chapter 1 presents an overview of the basic concepts of BIM technology. It provides fundamental notions related to the concept of BIM with regard to conceptual and technical dimensions.
Chapter 2 presents the different methods for collecting and acquiring 3D data for producing a digital model. This chapter provides an overview of the most common 3D acquisition techniques and tools, with an extended reflection on 3D surveys of urban environments in general, prior to the production of urban models. This chapter also proposes a discussion around the choice of techniques and methods and the integration of multiple and heterogeneous data sources for the 3D reality capture of urban space.
Chapter 3 addresses the modeling methods for the development of a multi-scale BIM. This chapter presents the basis for the production of a digital 3D mock-up and the main approaches developed for 3D reconstruction of its objects, in particular buildings.
Chapter 4 deals with the interoperability of models and gives a global overview on Open BIM standards offering the possibility for professionals to work in an exchange environment that guarantees the interoperability of software within the framework of the “open” and standardized digital mock-up.
Chapter 5 explains the principle of combining BIM and GIS technologies under the concept of GeoBIM. It highlights the benefits of GeoBIM with respect to several topics and discusses the latest research findings in this area.
This theoretical and technical analysis is supported by three chapters presenting three case studies:
– BIM and 3D GIS integration for real estate valuation (Chapter 6);
– semantic segmentation of airborne LiDAR data for urban model development (Chapter 7);
– use of BIM models for the renovation of urban spaces (Chapter 8).
Finally, the book ends with a general conclusion that summarizes the highlights of the concept of “multi-scale BIM” by posing some perspectives on the subject.
Target audience
Because of its content covering the multi-dimensional aspect of multi-scale modeling of urban spaces, this book is intended for a large community of professionals working in the field of land use planning, urbanism, architecture, civil engineering, topographic engineering and geomatics, as well as researchers, academics and doctoral students wishing to specialize in the field of BIM applied to territorial and urban intelligence.