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What is BIM? – a look into the technology that is revolutionising the building industry

Written by Ole Kristian Kvarsvik

Most people in the building industry have heard of BIM, but have they actually understood the revolution we are facing?

“Productivity in the building and construction industry has decreased by 10% since 2000. In the same period, productivity in the private sector in mainland Norway has increased by 30%.” Statistics Norway, 19 January 2018

I have worked with BIM in the building industry for 20 years, and believe we are facing a revolution in building.

The technology is ready.

The industry is (largely) ready.  

Awareness still has some way to go.

If we are going to reverse the negative trend in our industry, we have to recognise the huge potential that is inherent in BIM – when used as it is supposed to be used: By all participants and in all phases of the building process.  

With this article I will explain what I believe BIM entails in practice for project engineering, building, operation, and use.

BIM changes everything

BIM is comprehensive. Before I go in depth, let’s take a step back.

From pre-engineering and the first breaking of ground, to final inspection and maintenance or remodelling, BIM affects everything and everyone who builds or uses the building throughout the building’s lifetime.

  • BIM increases understanding of what the finished product will be.
  • BIM raises quality assurance to a new level.
  • BIM is an unrivalled platform for communication.
  • Data is localised – it is here BIM really starts to become valuable.
  • From “push” to “pull” at the building site – retrieve the information you need yourself.
  • BIM facilitates painless documentation of own work – for the benefit of everyone.
  • BIM adds value in a life cycle perspective – for all parties.

In sum, this means that BIM creates a sustainable and competitive building and construction industry. Some challenges remain, and we will return to them at the very end.

Want to know more? Then let’s get started.

How StreamBIM boosts productivity at every stage of your construction project

From drawings to models

Imagine large paper scrolls of sketches of bridges, schools and hospitals. Intricate detailed drawings of trusses, window constructions and ventilation ducts.

A workday for architects and engineers has traditionally comprised drawing. They also write applications and descriptions and supervise the building process (and tear their hair out), but when all is said and done, their main product has traditionally been qualified creativity translated into tangible drawings.

Indeed, drawings. Pencil behind the ear. Ruler and compass. More recently the work has taken place on screen, but it has nevertheless been drawing. Today, however, more and more building projects are based on BIM. There, drawing is not the order of the day – modelling is.  

Drawing as opposed to modelling may perhaps just sound like terminology, but in practice it entails a fundamental change for buildings and everyone who builds.

BIM is an acronym for Building Information Modelling, and the I – Information – is the key letter. A line in a traditional drawing is just a line – ink on paper or pixels on a screen. A line in BIM on the other hand, is a part of an object and contains information.

Traditional CAD, where a line is a line.
Modelling in BIM where “a line” is a wall (in this case).

Where architects and engineers previously drew using a pencil or cursor, one now “draws” using structural elements. In the BIM application one can for example choose Lining wall, 125 mm, insulated, studding with fibre plaster and draw it as long as one wants. Information on the object is available at the click of a mouse. Previously one had to explain exactly what each different line represented so that this was correctly interpreted by the recipient/viewer.

Many suppliers of different structural elements offer downloadable BIM objects of their products. Thus one may easily import and insert for example a door in the model, and automatically include all of its characteristics: actual geometry, fire class, weight, soundproofing, control and automation, link to product sheet and so forth.

Thus the model is enriched with high quality data, and one lays the foundation for different analyses using application extensions. This may be energy calculation, BREEAM surveying, costing or other.

One can still retrieve drawings from a model, for example a 2D floor plan or a cross-section, but this is just one possible “report” from BIM – a by-product of the model. The 3D model is a different report, a door list a third.

A 3D BIM model can look like this. It is evident that the building comprises different materials. The users can easily consider the floor plan. Also note the technical installations above the ceiling. 

BIM and the planners (at the office)

BIM provides interaction

Planners have always worked in communication with multiple disciplines, but it has been difficult to communicate what one has drawn between the different disciplines. With BIM everyone can work on the same model – from the start. Each party still works locally on their respective disciplinary models, but the result is uploaded to or synchronised with a so-called central file, where the models from the various disciplines are continuously collated.

Revision C…or was it H?

Previously the consulting engineers constantly imported new revisions of the architect’s (ARCs) documentation, and then exchanged their own drawings via a coordinator. This is time-consuming work; plan drawings often change in the design phase, and all parties must ensure that they are always working to the latest revision.

It is a vulnerable system that entails a high risk of duplication of work and delaying corrections. Why?

Producing drawings take time, and the traditional practice has been to exchange drawings at (construction cycle) milestones. This means that one usually works on “historic” drawings. Because all disciplines impact each other, if just one discipline is out of line, there could be significant extra work for everyone else. Delays accrue interest. The coordination of drawings is demanding and is therefore usually done on the basis of spot checks. One then hopes that the remainder (that aren’t checked) maintain the same quality.

The coordination of drawings is at least as significant a bottleneck when building starts. Most building processes entail registering non conformances and changes along the way, which is a key factor in most delays and budget overruns associated with building projects.  

What can this look like in practice? Let’s say that during the construction phase one discovers there is a sprinkler pipe where a cut-out (hole in the wall) was to be made for a ventilation duct. CEW (HVAC) must either find a new route for the duct, or must remove the sprinkler system that has just been installed. Another route might be to require that CEE (electrical) moves its cable bridge and associated supports, and the CEB (building) must approve an alternative cut-out in the supporting wall.

All this usually entails a few rounds at the planning office: With the exception of minor interventions, changes must be documented and checked by the consulting engineers. Once the new solutions are approved and coordinated, new drawings are produced – for example revision F – which is often sent by taxi to the building site while the tradespeople are standing around waiting.

In 2019 there are better solutions than transporting drawings by taxi (no, not Uber!).

Goodbye revisions!

With (open) BIM, it’s another world entirely. Computers can now assist in coordinating the disciplines for collision control and other automated analyses and quality assurance processes. Many BIM projects are still built based on drawings, but as we know, drawings are a byproduct of the models. Coordinated models thus produce buildable drawings.

There are further opportunities for projects that implement BIM at the building site. Tradespeople can use smartphones or tablets to upload real photographs of problems and link these to objects in the model, draft a possible solution, comment in the model, and notify the relevant stakeholders – directly from the building site.

The engineers are notified and can implement the required changes immediately, update and synchronise the updated model with the project hotel, where it in turn becomes immediately available to the team ready to proceed building. Because everyone works from the latest synchronized model, no one is in doubt about the latest solution (revision).

In BIM, ARC and the consulting engineers will constantly synchronise changes with the central file. One will still be able to distinguish between different revisions as the model develops, but all discipline models will be up to date.

This also makes collision control in BIM child’s play; you simply activate the layers of the various disciplines and check. For planners BIM means that one interacts to a much greater extent, because it is significantly easier to understand one another’s disciplines, and how one’s own contributions affect the others.

Drawing production a hindrance

In traditional planning you are assessed by drawing production. Efforts are thus directed at the delivery date, where it is important to have dimensioned and produced the required drawings. In a detailed project there may be tens or even hundreds of drawings per discipline. These must be plotted for control, corrected, saved in PDF format and distributed. This is an activity that doesn’t add any real value to the project beyond satisfying the formal delivery requirements.

Drawing production is thus a worthless activity that costs NOK 1,000–1,500 per hour.

In a (paperless) BIM project on the other hand, this time and expertise can instead be used to enrich the model, and therefore to plan a better building.

No one stops you mid-work to ask you to tag drawings and make prints; they just open the model on their tablet. The assumption is of course that the model is good enough to retrieve at least the same information that one previously could interpret from drawings.  It should be said that quality will follow if the measure of achievement is model oriented.

Reuse, not recreate

The building industry has been known as “the blank slate industry” – you start from scratch every time. But the great advantage of BIM is to reuse rather than recreate. With open BIM (independent BIM standard) one can take what has been created in previous processes and then enrich or refine the model before moving to the next work process.  

QC work

With constant new revisions and an endless number of produced drawings, there isn’t time to check everything. Even if there are adequate resources and skilled people, the reality is that everyday work is busy for almost everyone.

By letting the computer assist in quality assurance (for example collision control), consultants can instead concentrate on other areas.

In an interconnected and coordinated 3D model one sees the interdisciplinary problems in a completely different way. 2D drawings don’t say anything about height, the z axis, which is often where problems arise. For example one frequent problem is crossing ducts that don’t have sufficient space above the ceiling. This is typically resolved by adaptation at the building site (i.e. flattening), which has technical consequences for air flow. Those consequences may include greater power consumption, noise, reduced lifetime of the ventilation unit, and a reduced energy rating, which in turn may be reflected in rental income. Noise and a poor indoor climate will also affect the users’ productivity.

It is therefore significantly cheaper to collide digitally than in steel and concrete at the building site. If something collides in the model, it’s possible to find alternative solutions that are fully functional, while a collision at the building site means that a quick fix has to be implemented without testing the unintended consequences (the hole must be made today – the users are expecting to move in next Monday).  

The quality of everything that has to be resolved at the building site is at the mercy of the expertise and insight of the individual contractor and construction manager. My colleagues and I often see solutions that should have been quality-assured earlier – with a cheaper solution as the result.  


Anyone who has been involved in the renovation of old buildings knows that the quality of existing drawing documentation can vary widely. The original drawings may be good enough, but in 100 years it is likely that major changes and renovations have taken place, which are not captured in old documentation.

Many buildings that are delivered from projects today are remodelled soon after. In other words, it takes far fewer than 100 years before the drawing documentation is out of date. Drawings may be “dying” only months after completion.

It is often undocumented measures that subsequently make it difficult to perform necessary upgrades. Original pipe and ventilation systems may for example have been removed, while new ones may be concealed in walls or above fixed ceilings. Then already tight budgets must be used for time-consuming assessments.

Often enough it is the ventilation system that is to be upgraded. Fine – where are the ducts? You see that they start up in the attic, but then they disappear down a 10 metre shaft. Do they extend to the third floor? Second floor? Where is the damper on the main duct? Is the duct blocked by an old mattress? Nobody knows.

Time is money, and it is not uncommon that the actual assessment becomes so expensive that there’s no money left for the rest of the project.

Rehabilitating a building that has been planned and followed up in accordance with good BIM practice will be something else entirely. If one manages to integrate the models in the day-to-day operation and development of the building, it will be possible to keep the models (and any drawings) alive.

Many think that this requires that the CMMS application can read/import BIM formats and have an integrated 3D viewer. This isn’t necessarily the case. But it does require that one has structured data in the models that allows communication between the model and CMMS software. Then it will be possible to click on an object, see maintenance history, create work orders and more, completely without the CMMS software knowing the first thing about BIM.

By configuring the CMMS software in this way, one may efficiently report “red lines,” i.e. discrepancies between the physical solution and the models, to those who maintain the geometric models and drawings. In theory, you can thus have an up-to-date basis available in a matter of minutes. One simply becomes capable of keeping models and drawings alive.  

BIM and the contractors (at the building site)

It is reasonable to distinguish between planners and contractors, but the divide should not constitute a barrier. For two groups that are so dependent on one other, it’s a paradox that until now it has been so hard to achieve a flexible communication flow. With BIM at all stages, the situation is completely different.

From push to pull

Traditionally, interaction between planners and contractors has been characterised by push – consultants have produced and distributed drawings with selected measurements and descriptions. The desire has been to provide the people doing the actual building with as much relevant information as possible.

Clear as ink: When a drawing is revised at the building site, it no longer matches the office drawings, which means the plans are no longer clear or accurate.  

With BIM at the building site, this dynamic changes to pull: The contractor retrieves the relevant view. For builders and other trades it is liberating to be able to retrieve the necessary information and desired measurements directly from the model at the building site instead of asking the planner to send a drawing that is dimensioned and tagged according to the planner’s own perception – far from where the building is actually being erected.  

Fewer errors

In the same way that it is easy to take the wrong route when using an old map, problems often arise when building according to an old revision. A BIM viewer on a handheld device allows workers/project members to study the latest model – straight from your pocket at the building site.

Producing and distributing drawings takes time, which is typically in short supply during the building phase. If consultants can draw changes and make them accessible to the building site with the click of a button it will reduce the risk of errors.


One of the most important things BIM has to offer in the building phase is the opportunity to document work as it progresses directly within the model.

Did you install underfloor heating? Take a photo before the floor is cast and upload it to the model – directly in the correct room. Did someone spackle the electrical outlets? Document and link to the correct room in the model before making repairs to ensure the cost is borne by the right person.

That time the stream flooded the basement – troubleshooting with StreamBIM

BIM and the building’s users (customer)

Better understanding

Few end users have the knowledge required to imagine a room based on a floor plan. In BIM projects, however, anyone can perform virtual inspections via handheld devices or a personal computer – whether they are on their daily commute or in the office. Navigating the three-dimensional building within the model provides a more thorough understanding of how the final product will look.

In other words, BIM provides the building process with usability that is in keeping with how most people are accustomed to using IT – if you can cope with Google Maps, you can already use a model in open BIM.

Greater degree of involvement

The problem with the traditional approach is that the programme description, i.e. the order from the owner, often ends up in a drawer as soon as planning starts. Then as the course gradually changes, the finished building may not correspond with the customer’s original plans or expectations.

User involvement throughout the process is necessary for success.

With BIM, users can participate in the model at an early stage and also be a part of the entire building process up until handover.

In the draft phase, it’s beneficial to receive feedback from those who will be using the building every day. What do you need to do your job? Who will be working together? What should the flow of the building be like? How should the rooms be positioned to achieve optimum interaction and function? Physical orientation?

Once planning is well under way, one will want more detailed feedback. Is an entrance missing a wheelchair ramp? Click on the entrance area and comment. Should there be only partial ceiling lighting? Click on the applicable ceiling tiles and comment.

Frequent user involvement will also act to clarify expectations, as the users will be aware of any adjustments along the way – in good time before completion.

BIM and MOMD – a revelation

Can a mechanic do his work without looking under the hood?

It’s difficult to exaggerate how important BIM can be for those tasked with operating a building.

Modern buildings are chock full electromechanics, heating and cooling systems, sprinkler systems, lifts, heating cables, alarms and so on. In process industry such things will be open and accessible, but in buildings one attempts to hide these systems as much as possible.

Most people think this is great – with the exception of those who operate the building (just ask them what they think of fixed ceilings).

In a BIM project, developers can document the execution of technical installations and link them to the right place directly in the model. When done right, an operations engineer will be able to seek out the room where the equipment in question is installed, for example by using a TFM code. If the ceiling is clicked, the developer’s as-built documentation (photos, description) for the specific ceiling will be available where it is of use.

Without dislodging a single ceiling tile, the operations engineer can thus see what is otherwise hidden – without having to search through hundreds of pages in a binder or a shoddily maintained project folder.

With smoother operation and maintenance, the risk of long-term operational disruption is reduced. This means that the building remains usable, which in turn means maintained user activity and better economy – for the users as well as the owners of the building.

Not least – in certain buildings such as hospitals and schools, operational disruptions may have consequences that can’t be measured in money.

For the property developer (owner of the model)

If you own buildings, you should also own the data that describes them. Today it is often the case that building data are locked in the software in which they are created. If you have a Word document, it is best to open and edit the document in Microsoft Word. However, if you save the Word document as a PDF, you will be able to open and read it in many different applications.

The same applies to CAD and BIM files. If you are going to take ownership of the data that describes the buildings, you must request open BIM formats. You will then be able to bring these data into other tools which allow you to reuse, update, and manage the information in a suitable application at any time. Open BIM is also an excellent archive format. I would go so far as to promise that files stored in 2019 will be possible to open with free viewer applications in 2040 without loss of data.

If we are to progress as an industry, building owners must take ownership of their own building data.

What challenges remain with BIM?

BIM is not fully utilized

BIM is often called an innovation, but it has been used in the Norwegian building industry for more than 20 years. Meantime, contractual arrangements and project implementations have stuck to the old recipe. Thus large amounts of good data have been generated that have not been exploited because drawings have retained legal priority over BIM. Contractors are still  assessed by their ability to deliver drawings in BIM projects. Unsurprisingly these contractors have become experts at delivering drawings in order to meet the standards of their contracts.

Unfortunately, the consequence is that drawing production takes priority over modelling good models. The contractual arrangements are thus an obstacle to development, which is something the clients must deal with.

Large data volumes can be useful, but we must create good processes and procedures to manage and structure information flow. It must be predictable for all involved parties which data is available, when it is available, and where it may be found. Improper processes can lead to a lot of noise. This isn’t difficult to achieve, but it must be given priority by project management.


For some disciplines, a paperless building process entails a major reorganisation. For example, technical contractors are used to symbol-based guides and communication on drawings. It can be difficult for them to adapt to a completely new “language.” At the same time, most people realise that in sum BIM eases their work, and their willingness to change is improving.

This also applies in the transitional phase. While the contractors are still more comfortable with (paper) drawings, it is very useful to have access to the model at the building site. Some contractors employ a workflow that uses working drawing as previously, but with the support of the 3D model on a handheld device enabling contractors or project managers to find answers to many questions that previously would have halted progress.

Contract documentation

One of the major reasons for limited growth in BIM use so far is that contract documentation continues to revolve around drawing deliveries: The planner must deliver x number of drawings to instruct the building, so that the finished project meets the targets as they were designed in the planning phase. For example, if the customer is unhappy with a part of the building and the area in question has been built in accordance with drawing number 300, revision C, it is possible to identify whether the error arose in the planning or building phase.

So far not many contracts have been drawn up that define the model as a contractual deliverable. When building according to a virtual model, which party is responsible for defining the correct view that will be the criteria for assessment?

This legal vacuum is challenging; you model in BIM, but are evaluated by the drawing delivery. As long as this has been the norm, traditional drawings have been given priority over spending more time creating good BIM models.

However! Now the means are in place. BIM tools are constantly improving, and if one isn’t going to stop producing drawings entirely, it’s already possible to limit their use significantly.

Fees – how does one reward the good model builders?

By reusing rather than recreating, there is a risk that consultants are not adequately compensated for the extra effort required to create high quality models in the early stages of the planning phase.

In order to produce high quality models one must spend more time for documentation in the early phases than previously so that others benefit downstream. In other words it’s not necessarily the one who puts in the extra effort to create good models that reaps the benefits.

Traditional project budgets don’t provide consultants the leeway to create that value for later users. It is a paradox, because it is cheapest – and easiest – to stake the course and make good choices in the early phases. It also boosts the scope of assumptions in order to reach various quality goals (BREEAM Excellent and similar).

BIM is used in parallel with traditional solutions

The intention is to replace the old with the new, but offices that have adopted BIM have largely adopted new modes  in addition to what they have previously done, which has led to a kind of hybrid solution where outdated methods have continued to slow real progress.

Internal discussions must thus not only concern “what shall we start doing,” but also  “what shall we stop doing.” The production of x number of drawings is a good example.

BIM changes everything – a summary

BIM increases understanding of what the finished product will be.

With the right platform, all information becomes available to everyone – during planning, user participation, engineering, interdisciplinary collision control, interface management, documentation, VDC processes, Management, Operations, Management (MOM)  and so on. I usually call it transparent processes.

With BIM, project participants and other involved parties can understand the documentation and what is being discussed. They can thus contribute constructively to dialogue on solutions and choices – because everyone sees the same thing.

BIM takes quality assurance to a new level.

As a client and future user of the building, success factor number one is that you are capable of quality assuring what you have ordered – continuously. BIM enables you to do this.

BIM is an unrivalled platform for communication.

Communication failure is a factor in almost everything that goes wrong in building projects.

It doesn’t work unless all parties communicate with each other unambiguously. Professionals and non-professionals must be in agreement, such that the building and the model are in harmony with each other. This is also essential in order to rationalise the operation and management phase.

From “push” to “pull” at the building site – retrieve the information you need yourself

In production it’s about translating what is engineered into a physical result, and once again it’s about understanding what is to be built and having access to the information you need to do the job.

BIM enables you to retrieve what you need yourself. In addition, there are almost endless opportunities to integrate quality assurance and documentation in the models.

Data is localised

One of the really great benefits of BIM is that all data are localised. If you’re looking for data at a specific place in the building, you can easily navigate there and see which data are available, for example photographic documentation, engineered solutions above the ceiling/in the wall, or other things.

BIM facilitates painless documentation of own work – for the benefit of everyone.

By using BIM you create processes and document/collect information that benefit other work processes downstream. When the models are used for documentation of own work, you have also created great value for those who are to take over the building.

BIM adds value in a life cycle perspective – for all parties.

By using models as a skeleton we can build upon through all of the building’s phases, we create value in a life cycle perspective. With the right tools, we keep one another up to date.

Good luck with BIM! Don’t hesitate to get in touch if there’s anything you want to know, and feel free to share the article with friends and colleagues.

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