BIM Interoperability

BIM chapter 3 was interesting, but very difficult to read and absorb the information. Despite that, I learned several important points from it, which both answered some questions I had and awaked an interest in the future of BIM (regarding the interoperability). It has been clear for a while to me, and it was once more verified, that interoperability still remains one of the “hot topics” in AEC industry, as it is transitioning to BIM. There are quite a few exchange formats, but most of them are very “user” or “project” specific (translating object based model to an energy analysis). Based on this reading assignment as well as my personal experience of discussing the matter with industry professionals, there still is a need for a full interoperability of fully editable models both ways. This raises several issues, concerning proprietary programming and BIM platform developers need to remain competitive, which the reading assignment did not elaborate on.

Articles chosen:

• Value proposition on interoperability of BIM and collaborative working environments

The assigned reading concentrated on the technical (software) interoperability, whereas the article I chose expanded the interoperability definition to also include as an activity, which includes change in how AEC industry conducts its business. Interoperability is not only technological concern, but different AEC industry branches, instead of avoiding direct contact with one another, now have to collaborate throughout the design process, changing their manner of business, in addition to new software implementations. In truth, BIM interoperability has to address all technical concerns, AEC cultural adaptations, business practices, and new legal issues. This article raises a very valid oint (without answering it), that there is a strong need to determine the actual (productivity and financial) value of BIM interoperability.

• BIM Test At ASHRAE HQ

This article is of the type I have been searching this entire term – an actual BIM model conversion from IFC to usable working model test. ASHRAE Headquarters building was renovated, and they used this opportunity to test BIM for energy modeling. This was to be done by converting a 2-year old model from one BIM platform to another using Industry Foundation Classes (IFCs). At the beginning, the progress of converting the model, cleaning it up and modeling Load Calculations seemed promising, but after the model was run, the result were unreasonably low. After a careful investigation, they discovered, that even though exterior element such as doors and windows were converted (visually) the new BIM software was not able to recognize it for the analysis purposes. At the end the following conclusions was reached by the design team: “The effort to clean up the IFC model far exceeded the time to create a new native BIM model”. While this is not good news, it was refreshing to read about the reality of IFC capabilities as it relates to today’s industry. I only hope, that as more similar examples emerge, the development and improvement of IFCs will grow, because it has some great potential for the future of BIM.

Data Interchange Reading

            The required reading discusses the problems and challenges with interoperability between different BIM systems.  Each BIM application has its own file format which is usually not compatible with other systems.  If there was a universal file format, then models could be exchanged freely to take advantage of the various features that each BIM tool offers.  This free exchange would be useful throughout a building’s life cycle.  The reading discusses Industry Foundation Classes (IFCs), which attempt to solve the data interchange issues.  IFCs are limited because they must be updated frequently in response to changes in BIM software so they lag behind the updates.

            My second reading also relates to data interchange and IFC issues.  I read “The Role of IFC for Sustainable BIM Data Management,” a research paper that presents the results of a preliminary analysis into IFC data interchange.  The authors are investigating the differences in coding when importing and exporting IFC files from different BIM applications.  For the preliminary investigation, this involved the files created from a wall component with identical properties that was generated in both Revit Architecture and ArchiCAD.  They created four IFC files by: exporting from Revit, exporting from ArchiCAD, importing the Revit file into ArchiCAD and exporting, and importing the ArchiCAD file into Revit and exporting.  The coding of each file was analyzed to determine any differences.

            The analysis showed that the number of lines in the code and the types of IFC entities were different for each file.  About 78% of the coding entities are common to all four files, but only 54% of the entities are seen in the same quantity in each file.  The analysis provides insight into how different BIM tools generate files, for example, Revit created 2D axis information.  This insight into IFC file generation shows the issues that still remain for interoperability.  The data can be used to make data interchange more efficient.  More efficient data exchange results in sustainable data that can be used throughout a building’s life cycle, from the design to facility management.  Sustainable data is an important part of BIM design that saves time and resources.

BIM Interoperability

This week's reading focused on the issue of building information modeling interoperability. After reading the assigned reading, I've gained an appreciation for some of the software engineering issues which enable the passing of data between applications. As an industry, this is something that we have struggled with, beginning in the 80s with the earliest CAD software, and today, with the pallate of sophisticated BIM and analysis software. It's comforting to read about the effort to standardize data, known as the National BIM Standards project (NBIMS). However, as the Bentley representave alluded to in class, it seems like part of the problem is the software manufacturers unwilling to open up properitary file formats to other vendor's software. A joint and open alliance between Bentley, Autodesk, and other BIM providers would be paramount in overcoming the interoperability issues that the industry currently faces.

One of the additional articles that I read this week was titled "BIM Interoperability." This article discusses the story of information flow as it travels from the design professionals (read: actual hunam beings) to the BIM system, then to the design and analysis software, to the fabricator, to the contractor, and finally to the owner. At the present time, the workflow of data between the BIM system and the analysis software is currently strangled by the lack of design or analytical capabilities in BIM software. Rather than complete the analysis in BIM software, the design must be exported to a 3rd party design and analysis software, such as RISA 3D, RAM Steel, or SAP2000, through an inefficient exportation process. This process is shown in the following chart:

In the future, hopefully interoperability standards will be more defined, and programs like Revit and Microstation will include analysis tools within the software. This seems to be the direction that Bentley is going in with their latest software.

The other article that I read this week was the National Building Information Modeling Standard, which is produced by the National Institute of Building Sciences. One of the most interesting things I found in this standard is the justification for why a BIM standard is necessary. In this section, the following graph highlights the potential game-changing impact that BIM can have on the construction industry:

Thus, the effects of BIM interoperability are incredibly consequential. Hopefully the industry can adopt standards faster and more efficiently than it has with computer aided design throughout the past three decades.

Reading 5- Data Interchange

The article which was assigned to us this week for reading was about data interchange and interoperability. AS was said by many others who have posted, this is a very important concept within BIM and intelligent building design. The assigned reading article discussed what the different types of interoperability are, and what different kinds of exchange formats are being used throughout the AEC industry. Although the article was relevant to what we are study, it was a little bit hard to read and follow as the information which it provided was dry and tedious. Ultimately though the main idea of interoperability which it discussed is important as it speeds up building design and makes transfer of data more consistent.

One of the main concepts discussed within the assigned reading article was the idea of IFC. Since I was curious to find out more information about this, the two other articles I read focused on this concept. The articles I read were:

"The IFC Building Model: A Look Under the Hood"
"The Implementation of Industry Foundation Classes in Simulation Tools for the Building Industry"

The article "The IFC Building Model: A Look Under the Hood" was an article which summarized IFC and how it relates to interoperability. As opposed to the assigned reading, this article broke down what IFC was in a more easy to understand way. It emphasized the fact that IFC models use building-specific data models, which is ultimately what BIM is. It also discusses the idea that IFC is composed of four different layers, which makes it a more appropriate tool in terms of interoperability. This is because within the layers there are entities. According to the article, some of these entities may contain IFC-compliant parameters which are interoperable and therefore can be transferred between different programs. This creates interoperability between software applications, and in the future will help to create a more cohesive AEC field.

The article “The Implementation of Industry Foundation Classes in Simulation Tools for the
Building Industry” is another article about what IFC is, but it also discusses how it was developed and what is being done to develop it more. One of the most important things that the article discusses is the idea that a software program must be IFC-compliant in order to be interoperable within an IFC model. This was one of the ideas that was also discussed within the first article I read. This article however talked about the fact that there are different levels of IFC-compliancy. For example, a IFC model can be fully-compliant, partially-complaint, or non-compliant. This is an interesting idea because it means that even if a software program didn't want to become a complete IFC-model, it could change some of its programming to accept some IFC information (or be partially-compliant). Ultimately though, the most important thing discussed within the article was the idea that if IFC is implemented correctly throughout software programs in the future, it can eventually “provide an environment of true interoperability for building simulation tools.” (Bazjanac, et. al., 1997).