What BIM is?

 Termín BIM se začíná čím dál častěji objevovat i v médiích, např. v souvislosti s usnesením vlády o zavádění metodiky BIM v ČR. A to je dobře! S tím však také přichází dotazy od lidí, kteří se nepohybují přímo v oblasti stavebnictví, co se vlastně pod tou magickou zkratkou BIM skrývá?!

Building Information Modelling or Building Information Management (abbreviated to BIM) is the process of creating and managing data about a building throughout its lifecycle. BIM is fundamentally a digital model that represents a physical and functional object together with its characteristics. It serves as an open database of information about a building for its construction and operation throughout its lifecycle, and enables the effective sharing of information among all participants in the construction process.

BIM needs to be seen primarily as a process, and when transferring to BIM it is therefore essential to understand that this is not merely about installing a new software tool, but is a more fundamental change in the overall system of work, whether we are considering the designer – an individual – or more likely the whole project team. The introduction of BIM technology will bring about a definite change in thinking as regards working procedures and habits, and will essentially lead to a new methodology of work – ideally, cooperation between everybody in real time on a single model of the building. This mental shift is often compared to the shift from the drawing board to design using CAD tools. Working with BIM is mainly about how to organise and enter as much information as possible about the building directly into the properties of its individual functional elements (the model). The ideal BIM model is one that carries all the necessary information as data items for each element in such detail that information in a different form is not needed to describe the building.

The exchange and sharing of building information and data between applications developed by various software producers uses the IFC (Industry Foundation Classes) open file format developed by the international buildingSMART association. In the majority of activities, we see a need for increased interoperability, use of IT resources, and use of independent and documented data formats. As it is open, the IFC format does not belong to any single software supplier – it is neutral and independent of any specific software producer. IFC is forms the BIM standard for sharing data – Open BIM. Every IFC implementation should comply with the rules for the so-called Exchange Requirements in a way appropriate to the stage of the construction project currently being implemented. The IFC standard is based on the international technical standard ISO 16739:2013, which has been adopted into the system of Czech technical standards under the designation ČSN ISO 16739 – Data Format Industry Foundation Classes (IFC) for sharing data in construction and in facility management.

The IFC specification focuses on supporting various disciplines that participate in a construction project throughout the building lifecycle. The data are generated and gradually supplemented and used by applications from disciplines like architecture, facility technical services (HVAC – heating, ventilation and air conditioning, cooling and electrical wiring), building automation, structural analysis and structural engineering, applications for working with bills of quantities and estimates of costs, construction planning and implementation, handover and its management, including potential demolition.


IFC contains definitions of charts for:

• a complete catalogue of construction elements, including HVAC;
• a department of general and parametric object definitions;
• steel and wooden structures;
• structural analysis – analyses and details;
• standardised statement of materials;
• energy and other analyses;
• environmental impact;
• spatial planning and links to GIS;
• coordinate system for GIS and its transformation;
• language packs (currently limited selection of languages);
• data for 4D (scheduling, MS Project support);
• data for 5D (price);
• expansion for possible building geometry (NURBS, non-planar surfaces).

The IFC specification describes an information model written in the EXPRESS language (ISO 10303-11:1994) and enables data sharing in the construction industry. It is the same method used for CIS/2 using the STEP file structure (ISO 10303-21:1994). It is a text file that can easily be used for transferring data between various applications.

The IFC initiative was started in 1994, when Autodesk established an industry consortium for the development of C++ classes supporting application development. This consortium, originally called the Industry Alliance for Interoperability, changed its name to the International Alliance for Interoperability (IAI) in 1997, and then to buildingSMART in 2005.

The members of the international buildingSMART alliance initiated the Open BIM idea. Open BIM is a modern approach to interdisciplinary cooperation between individual partners in AEC. The goal of the Open BIM activity is to help coordinate efforts in the promotion and introduction of workflows through Open BIM. For example, by providing common definitions, requirements and labelling. The Open BIM community is constantly growing. The Czech www.openbim.cz website is managed by the Czech BIM Council. The Open BIM idea is nicely explained in a short video here.

The Czech BIM Council is an organisation that wants to focus on Building Information Modelling systematically and over the long term, not only from the perspective of international application, but also with regard to the specifics of the Czech environment (standards, legislation etc.) in practice. Our company, di5 architekti inženýři, which is involved in the development of the Bim.Point tool, is an active collective member of the Czech BIM Council.

 


Recources:
ČSN ISO 16739 Data Format Industry Foundation Classes (IFC) for sharing data in the construction industry and in facility management. Prague: Czech Office for Standards, Metrology and Testing, August 2014. 4 pages + CD ROM. Classification mark 73 0109.

https://cs.wikipedia.org/wiki/Informa%C4%8Dn%C3%AD_model_budovy
https://cs.wikipedia.org/wiki/Industry_Foundation_Classes
http://buildingsmart.org/
http://www.openbim.cz/
http://www.czbim.org/
http://www.di5.cz/

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