By Neil Calvert
A post entitled "BIM – Worthy of Clearer Definitions" was published on Directions Magazine on the 31st October.
This was followed up by a podcast called "The State of BIM" on the 5th November.
These tended to suggest that Building Information Modelling (BIM) was just 3D GIS. My opinion on that; they couldn't be more wrong. To think of BIM as just 3D GIS strikes of the beginnings of a turf war where GIS professionals, concerned about other professionals being able to call themselves spatial experts, demean what BIM really is.
Some of the comments made which really show that GIS professionals have much to learn include:
"BIM has nearly reached the status of GIS." This is such an unfair statement to make; the assumption is that BIM is inferior to GIS. That is simply wrong.
"Isn't BIM GIS for the Built Environment, or infrastructure; that is, the combination of CAD and a database providing intelligence to the graphics? I don't think BIM is any more 3D than GIS is … I think it is unfortunate that BIM has the word "building" in it. How about IIM - Infrastructure Information Management." So now our ignorance is solved by applying a name that we are more comfortable with! Really?
The webcast also discussed that BIM may be trying to model the whole of the built environment including street furniture. I have not seen any of that in my research other than the elements which allow for the presentation aspects of a BIM model as part of the public engagement process to be made more realistic.
One of the more positive discussion in the webcast included that perhaps GIS and BIM are two elements in the expanding field which we are calling Geodesign. I think this is closer to the truth; BIM is Geodesign at a more macro level than we would use GIS for. It is also for a specific area of expertise – the development and construction of buildings.
To hear GIS professionals be so defensive about another spatial science is not easy listening. The answer to the question is not "isn't GIS already doing that?" or "isn't that just 3D GIS?" it should be "how can we learn from and contribute to a science which has the potential to make a huge difference to the world we live in?" It isn't about collision – there is no need for there to be one winner – it's about collaboration.
If you don't yet know what it is, or why it is important, I would suggest that there is a simple solution. Do some homework. There are many excellent BIM resources available on the web which will quickly help you to identify what BIM is and how it applied to develop incredible return on investment figures. That is what we had to do as BIM was introduced to us and rather than seeing it and the people involved in it as a threat, we think there is a huge opportunity, which is why we are taking the time to ensure we understand what BIM is and importantly how it integrates to GIS.
Here is my ten point interpretation of BIM plus some links to additional resources for those of you interested in knowing more. As usual, we encourage a response to our blogs, so if you would like to join in the discussion, please don't hesitate to get in touch.
1. Most importantly, BIM is not a technology. It is a process. This is possibly the most important aspect to understand. BIM applies to all aspects of the construction of a building, from the design, the estimating, the supply chain, the delivery of goods during the build, the build process, the resource allocation, the productivity requirements to meet targets and on in to the post-handover phase through Facilities and Asset Management.
2. Aspects of BIM are enabled through various technology platforms. There are several providers of technology which supports architectural tools plus the addition of intelligent information against the model. Examples include Autodesk Revit[1], Graphisoft ArchiCAD 17[2], 12d Model [3] and Synchro [4].
3. BIM has several implementation levels:Level 0: CAD using drawings, lines, arcs, text, etc.
o Level 1: 2D & 3D using models, objects plus file based collaboration
o Level 2: BIMs plus file based collaboration and library management for models and objects and
o Level 3: iBIM, Lifestyle Management, common dictionaries, data and processes underpinned by integrated and interoperable data through web services
Level 2 BIM is often seen as the minimum standard to achieve. These levels are also split in to A and B, e.g. 2A and 2B which denotes the directionality of information sharing, i.e. one-way or multi-way. Here are two diagrams explaining the differences:
4. Industry Foundation Classes (IFC)[5] and COBie[6] are standards used to share information. IFCs describe building and construction industry data. It is a platform neutral, open file format developed by buildingSMART[7] to facilitate interoperability in the architecture, engineering and construction (AEC) industry. COBie is a data format for the publication of a subset of building model information focused on delivering building information and not geometric modelling. It is closely associated with BIM and is typically exchanged using XML. These formats enable BIM interoperability and all BIM software is able to consume this information. Most are able to write it, enabling the sharing of information, even at Level 2 BIM to be easily achieved. External software such as Safe Software Feature Manipulation Engine (FME)[8] is able to transform from IFC[9] and COBie[10] to other formats. This represents the beginnings of full integration possibilities between BIM and GIS.
5. BIM is so much more than just a detailed 3D model of a building. The concept is most easily explained by the term build 4 times which means build three times in the model and once on the ground. The accuracy of the model combined with animations and fly-throughs allow contractors to access the design layout beforethe build takes place and make alterations. This means that when the build takes place, there are fewer errors and far less rework needed. This moves the construction procurement process from design and build to design build by bringing the construction team in to the design process rather than them simply having to respond to a tender for construction after the design has been completed.
7. The 'D' elements of BIM relate to the information associated with the model.
o 4D relates to scheduling information; when will an element be built. With this information you can enable just-in-time (JIT) delivery of materials to site. This in turn has an impact on transportation, making it more efficient, and reduces storage issues as materials are delivered and immediately installed.
o 5D relates to the estimating and cost aspects of the building. Each element within the building model has a cost associated with it. This allows for detailed analysis to be done regarding budgets. It also allows the delivery team to make accurate predictions regarding how much needs to be done at any given time in order to meet the construction targets.
o 6D covers the sustainability targets for a building allowing information such as energy use, sustainability from a materials and management point of view to be understood and Leadership in Energy and Environmental Design (LEED) tracking to be performed.
o 7D is the "as-built" BIM model which is important as part of the handover process to the building owner. This model is a fundamental part of the ROI for BIM as it provide accurate Facilities Management (FM) and Asset Management (AM). Each part within the building will have a lifespan and in the event of replacement, the easy identification of parts ensures that these processes may be performed efficiently.
The outcomes from having this information are impressing detail regarding all aspects of the construction project. By the very nature of the BIM model, this information is already there, you simply have to ask for the output you need whether that is a financial plan or a resource plan.
8. BIM enables new procurement processes to take place which deliver certainty to all parties involved. A typical process might look like this:
o The design and construction teams are selected
o The design work is done and is reviewed by the construction team and other subject matter experts. This review identifies areas of rework.
o This process iterates 2 more times, the result is the best possible design.
o Generic objects may have been used for materials and/or equipment; these may now be replaced by specific models conforming to the IFC classes with known materials, costs and supply chain information associated with them. In this way, the full cost of the building, the suppliers and supply chain costs of materials and the installation methodology is known by everyone involved.
o The work can now start on site using the BIM to direct the build. Technology assists in the build by presenting the BIM information in the field as construction takes place. JIT delivery of materials keeps building efficient.
9. Governments around the world are now realising the benefits of BIM, especially for large construction funded with public money, and are beginning to mandate the use of BIM for these projects. When has that ever happened for GIS? The effect of this is to seed the industry to change. The reality is that the industry is moving this way anyway as they have already recognised the advantage of using BIM. The issue has been the slow adoption of the client to realise the benefits of the BIM approach – to the point that some are still rejecting the final as-built BIM model, considering it an unnecessary cost rather than realising that it will reduce the AM/FM costs of running the building. Given that government is often the client, it would appear that this is actually an internal issue between government agencies or even roles with the same government agency that needs to be resolved as quickly as possible.
The UK have appointed a "Head of BIM" within the Cabinet Office. David Philp's role is to accelerate the adoption of BIM and mandate its use.
The UK have appointed a "Head of BIM" within the Cabinet Office. David Philp's role is to accelerate the adoption of BIM and mandate its use.
10. The result of BIM is impressive ROI figures of the order that GIS implementations dream of!
Figure 5 - Taken from BluEnt[13]
· 20% reduction in build costs (buy 4, get one free!)
· 33% reduction is costs over the lifetime of the building
· 47% to 65% reduction in conflicts and re-work during construction
· 44% to 59% increase in the overall project quality
· 35% to 43% reduction in risk, better predictability of outcomes
· 34% to 40% better performing completed infrastructure
· 32% to 38% improvement in review and approval cycles
No comments:
Post a Comment
(“Post your comments below”),