Can BIM alone be used for Construction?

BIM is promoted as the future, the 'new way of doing things'. There is an assumption by BIM evangelists that the BIM model will be the receptacle of all information about a building, making drawings redundant. But is this really true? Is it even possible?

TRADITIONAL PRACTICE

For a contractor to build a building they need to know what they are building. The various sub-contractors and individual trades need enough information to first price their work, then to do their work. But these people do not just follow a set of instructions, they bring their own expertise. The vast majority of building trades require years of training, they are experts in their own right.
So what information do they need? They need to know the Design Intent of what they are doing. They need just enough information to provide a framework, working out the rest themselves. Provide any more information and it is likely the results will be sub-optimal and inefficient.

Current practice is to provide this information as drawings, schedules and specifications. Only relevant information is provided in these documents. If the location of something is not critical it is not dimensioned. If something has to be provided that complies with a description it is not necessarily included in drawings or schedules. If something is included in a schedule, it may not be included in drawings. Therefore, although these documents have never been a full description of the building, they are adequate to build it.

ENTER THE BIM MODEL

With a BIM model the building has to be completely modelled. You can't leave out a facade just because it is part of a design construct contract, you have to model something. And if something is in a schedule it has to be in the model. Unless every screw, bolt, flashing, seal etc. is modelled in 3D it is not possible to explain how things go together like a drawn detail does.
But most importantly, how do you explain Design Intent when all you can do is create a virtual object? How do you explain which attributes of the virtual object are critical, important, for guidance, or don't matter at all? For example every object has a precise location in the model, yet the precise location may not be important, and may actually be unpredictable because it depend on decisions that can only be made on site.

LOD (Level of Development) tables are an attempt to overcome this shortcoming. But they are not really up to the task. On the one hand an LOD table is not precise enough (how do you use an LOD table to explain that the height of (some) power outlets are critical, but the location along walls is not?). On the other hand, even with this cut down amount of information, LOD tables are becoming far too detailed and complex to be of practical use. The number of element types in a building run into the thousands, let alone the number of actual objects. To assign a LOD to every one, and then track that it is being followed in the model, for each stage of a project, is just not practical in the real world.

BIM TECHNOLOGY

None of this should be a surprise to those that work in the AEC industry. Certainly the authors of BIM software are aware of it.
Take Revit as an example. The model is displayed to us via 'views'. We then add notes, dimensions and other annotation to explain our intent. These views are then placed on sheets that can be printed to paper of electronic format (DWF, PDF etc), and exported as 2D CAD files. Revit utilizes traditional practice to solve the problem of communicating design intent.

Bentley are going a step further. They have an initiative called 'Hypermodel' (as in Hypertext) that shows references to other drawings and documents in the 3D model. It is not so much a method of providing design intent information in a BIM model, more like a hybrid solution, providing access to traditional means of communication directly from within a 3D model (as opposed to just from views, as Revit does).

To go back to the original question - is it possible that BIM models will replace drawings - the answer is yes and no.  Yes BIM models will one day be able to communicate design intent, but no, they won't be BIM models as we know them now. There will have to be some sort of added technology. And it is not just a technological problem. If every BIM software vendor has a different approach we will be no better off. It is not realistic to expect contractors and trades people to be familiar with a whole range of software products just to get the information they need to build a building. There has to be some kind of commonality - like drawings, schedules and specifications.
There are probably technologies out there that could do the job now, but with nothing definitive in sight I would say for the foreseeable future it will still be drawings, schedules and specifications. So what does that mean for the BIM models we do now?

SO WHAT IS A BIM MODEL?

Another way to look at it is to define a BIM model as something that is not intended, by itself, to communicate design intent or how to construct the building.
Rob Snyder, who is involved in Bentley's Hypermodel initiative, has succinctly defined the problem. To him the BIM model is the 'environment'. But this environment is not meaningful unless there are 'statements' about it. For example a drawing with notes, dimensions, details is a 'statement'. It only shows the portion of the 'environment' that is relevant, with added 'statements' to point out things that need to be communicated.

So a BIM model is not another way of documenting a building project. It can not communicate in it's own right. It's purpose is as a resource to create deliverables. To create construction documentation, to run structural, thermal and other analysis, to participate in FM, and a whole range other other uses.

PRACTICAL CONSEQUENCES

By treating a BIM model as a thing in itself confusion is avoided about where information that can be used to construct the building resides. This also clarifies where your contract documentation deliverables can be found.

That said, a BIM model may well be a client deliverable, but make it clear it is only provided as a resource for others to produce their deliverables. So by all means provide your BIM model to others outside the design team, but strip out all traces of documentation - views, sheets, schedules.
You can do this very quickly in Revit:

1. Create a 3D view only showing what you want to export.
2. Place that view of a sheet.
3. Find the sheet in the Project Browser, right click on it, select "Save as file...".

Keep the view and sheet and next time you only have to do step 3.

And make sure project BIM plans are only be about the BIM model. List documentation (production of drawings & schedules) as a BIM Use, but don't include anything about drafting standards or drawing production. These can be referenced in the BIM Plan, but should be completely separate documents.


So don't treat your BIM model as part of your documentation deliverable, and be clear to everyone, from your boss & colleagues to clients, contractors and trades, of this fact.

Real Collaboration - Working with Engineers

From comments I have garnered it seems the consensus is that engineers will have to model accurately for BIM to work. There was a lot of talk about the many issues that will need to be resolved, work practices that must change, and fees that need realignment, but no alternative strategy to create true BIM materialised.

In my previous post, Should engineers model accurately, Method 4 - Engineers Model Accurately was the only one that received any support, or even serious consideration.

The most common objection (from engineers) to modelling accurately was that "their fee didn't cover it", or "there isn't enough time", which is the same thing. This may well be true, but upon what basis do you ask for increased fees? One of the benefits of BIM, and in particular accurate BIM, is clash detection and avoidance. But can you really go to your client and say "pay me more and I'll reduce clashes between my designed elements and the rest of the building". What do you think they will say? They believe they are already paying you to ensure there are no clashes. As one commenter pointed out, the A/E industry has been getting away with not providing what they promise - fully coordinated design - for years.

Another common objection, was that using BIM software like Revit is more work than traditional CAD. This is just not true.
Whilst you do things in BIM software you don't do in CAD software, there are more things you don't have to do in BIM software that you do have to do in CAD software. As an example, at the request of the contractor we changed the names of some levels. In Revit this took less than a minute, just a simple text edit in one place. When we told the structural drafter, who is using CAD, he groaned as he now has to find, open, and edit every CAD file where these levels are referenced. I'm dreading telling him we are changing door frame sizes to doors in concrete walls. One parameter change for us, hours of stretching lines and redoing dimensions for him. Properly used (i.e. in the way it is designed to be used) Revit will decrease your workload. You won't get far arguing you should be paid more because your BIM software is harder or more time consuming to use (although you might get paid more if you are one of the few who can use it well).

And I can't avoid mentioning the recurring complaint about architects continually changing the design, which apparently is the bane of every engineer's working life and profit margin. Of course the cause of this really has nothing to do with BIM, or does it?
The name Revit is a portmanteau of 'Revise' and 'it'. It's original creators recognised that designing a building is a process of making changes, to optimize the building's design. And that a product that made making changes more efficient had a market. It was only later, after AutoDesk bought it, that the BIM idea took over. So Revit is software designed for making changes easy. And it does. Change one parameter and you can change the size of say, a door, across the BIM model and all drawings and schedules those doors appear in. Even dimensions on drawings change.
So architects using Revit may indeed be making changes to their model that are more vast, and doing it more often, than when they used CAD. Because they can, and because the job of architects is to optimize the design.
Revit Structure and MEP are Revit Architecture with some extra bits added. It is fundamentally the same software. So if engineers used Revit the same way architects do, they wouldn't have such a problem with design changes. They too could use their software to make vast and frequent changes with little extra work.
And who knows, they might also be able to do a better job, by optimizing the building's structural or services design. With the added bonus of annoying the architect with frequent changes!

What does Model Accurately mean?

Before continuing I just want to clarify some things that some commenters were confused about.
By accuracy I mean elements being represented as geometrically accurate 3D representations at their actual location, rather than symbolic representations. They don't need to be realistic (it is best if they aren't), but they do have to represent their spatial requirements.
What I don't mean is sloppy work, where the intention is to place it accurately but that hasn't happened. All AEC consultants can be guilty of this.
Elements need to be spatially accurate during the design process, not just at the end when construction commences. How else can the architect develop the design so services fit? It amazes me when engineers think they can come in at the end of a design they have had no meaningful input in to and expect their services to fit. Or expect the owner to finance an oversized building just so their services will easily fit and make their job easier.
Another clarification is that no-one expects (except BIM evangelists) every single element to be modelled accurately. As architects and engineers we are doing design intent, not a 100% virtual representation of the finished facility. Elements that are large and have specific spatial or location requirements, like ducts, plumbing pipes to falls, light fixtures, large cable trays, do need to be modelled accurately. But elements that are small and can run anywhere, like supply pipes and cabling, don't require as much accuracy. Some elements fall in between. For example power outlets might have a required height, but the exact location along the wall is not critical. So it is not necessary to model all wall studs just so power outlets can be located to avoid them.

In a practical sense, what can be done?

But it is not my intention to beat up on engineers. I feel their pain. Whilst engineers may not be able to argue for more fees, the reality is their fees probably are too low. In a free market fees paid are based on actual work performed, not what is promised or even should, in theory, be done. The other reality is this is not going to go away. Not all engineers have been forced into BIM projects yet, but eventually it will happen.

VALUE ADD
Whilst no-one can claim extra fees for better coordination, offering to provide evidence of coordination could be construed as an additional service. By evidence I mean actual clash reports, rather than just the promise that there will be no clashes. Another potential extra is providing IFC models. Both of these would involve additional work (and possibly software) to just to deliver, but the potential is there to value add. There may be other opportunities, properly used BIM software can leverage a lot of down-stream processes.

BE MORE EFFICIENT
Utilize your BIM software to improve your work practices and work flows. Unlike CAD, which is just a generic drawing package, BIM software is designed with your workflows in mind. For example Revit MEP and Revit Structure are designed to link into analysis software. Revit has a workflow for monitoring changes in linked models (like the Architect's model) called Copy/Monitor. Some commenters reported a lot of success with Copy/Monitor. Some complained it was 'too hard', but I suspect those people weren't committed to making it work. Don't fight your BIM software, use it to its full advantage.

TAKE ADVANTAGE OF COLLABORATION
There is an expectation that BIM will involve collaboration. If a client mandates BIM, you can bet they assume collaboration will occur. But what does that mean on the ground? As I have said elsewhere, my definition of collaboration is mutually beneficial cooperation. You scratch my back, and I'll scratch yours.
If the architects say they want you to accurately place power outlets, ask them to do something in return for you. I hear a lot of bitching from engineers about being dudded by architects, but when I ask them what I can do to help (as the architect) I don't get a definitive request to do anything specific, just more bitching. So don't be afraid of asking, but make sure you are explicit about what you want. Just asking the architect to not keep changing the design is not going to do you any good.

Some suggestions (from a non-engineer):

• Get some commitment that the architects model will be to a certain quality:
  - existing elements will be edited rather then deleted and remade.
  - objects hosted to level or floor rather than wall, floors or ceilings.
  - each ceiling has its own level.
  and make sure to let them know if they don't keep these commitments.
• Ask the architect to set up views in their model that you can use. If they won't do it ask if you can come into their office and set them up in their model. Might save you from having to recreate views every time you get an updated model. 
• Ask the architect to use your families. Or at least start of with your families, it probably doesn't matter if they change a family's appearance as long as all the connectors and your parameters are still there.

I'm sure there are many others engineers have dear to their hearts. Don't be afraid to ask. If you face resistance remind them of their duty to collaborate. Offer to do things that help them. Remember it is all about cooperation and negotiation.


So for all you struggling engineers out there, there is hope. Admittedly there is the hurdle of learning your BIM software, but once through that (and it does end), there are practical things you can do to lessen your load to compensate for having to model accurately.

Should Engineers model accurately?

Here in Australia (I assume it is the similar elsewhere) engineers (M, E, P, and Structural) are responsible for specifying what things are and how many there are, but the architect is responsible for location. So traditionally engineers only need to show their objects schematically, whilst the architect has to show those same objects (or at least the ones that are visible) at their actual size and exact location so they can be dimensioned.
Examples include structural elements (like columns) on setout plans, A/C register and lights on ceiling plans, electric and data outlet on wall elevations, plumbing fixture locations on plans and elevations.

The theory behind BIM tells us that we shouldn't have duplicates of elements in the model. Besides waiting for the nirvana of Integrated Project Delivery (IPD) and the single BIM model how do we deal with this problem in a practical way?


METHOD 1:
Only objects authored by the architect are official BIM information.
Elements may be duplicated but only the architect's version is used for BIM. Effectively the architect becomes a drafting service for other consultants on the project.
Problems:

• architects would have to duplicate all engineer designed objects, even ones not relevant to design intent (like ducts above ceilings, plant, switchboards etc).
• all engineering data accompanying these elements would also have to be duplicated within those elements.
• the benefits of engineers using BIM software for analysis diminishes if there is no need for them to author BIM data.
• adds significant extra work and legal liability for architects, a liability possibly not covered by PI insurance. 

Summary:
Probably the reality on many current projects where engineers haven't taken up BIM, but not desirable into the future.
In theory possible on large IPD projects where BIM authoring for everyone is by a third party (the project BIM author?), but not a practical solution on the vast majority of building projects.


METHOD 2:
The architect can move objects authored by engineers.
The engineers accurately model their elements but the architect has the ability (and authority) to move those elements.
Problems:

• not possible with current BIM authoring softwares.
• moving engineer's elements may affect the engineering design. For example moving a column may increase a beam span.
• moving engineer's elements may break the setup for analysis. Moving a ceiling register may disconnect it from the thermal analysis system.

Summary:
Maybe technically possible if software written to do it. Solves the architects problem, but adds to the engineers problems. The architect being able to make changes to engineers elements would be a legal minefield.
A hybrid could be a workflow that allows the architect to move objects in a copy of the engineer's BIM, that is then used by the engineers, after their review, to move their actual objects.


METHOD 3:
Elements are duplicated by different authors,
each version can only be used for specific purposes.
Each engineer authored element is flagged as only usable for scheduling, and each architect authored element flagged as only usable for location.
Problems:

• still duplicate elements in a BIM model.
• not practical, or even possible, with all current BIM authoring and reviewing softwares.
• introduces risk of wrong information being used. An LOD table buried in a BIM Execution plan is not going to stop an electrical apprentice using the wrong information.

Summary:
The reality on projects where Revit is used with no BIM requirements.
Technically possible if BIM software written to accommodate it. May also be possible within some BIM federating software with an appropriate setup/workflow.


METHOD 4:
Engineers model accurately.
Engineer authored elements are both geometrically accurate and placed accurately.
Problems:

• Additional modelling (drafting) work beyond current practice for engineering offices.
• greater co-ordination required as architects still have to instruct engineers where to place these  elements.
• potential program delays if engineers don't keep up with architect's design (particularly for distributed BIM like Revit).
• allied workflow issues - do engineers also provide BIM for the architect's design options and design studies or do architects duplicate engineer's elements for these?

Summary:
If engineers say they are doing BIM, or are required to by their agreements, this is (according to BIM theory) what they should be doing.
On the face of it engineers would be required to provide more than they have in the past - accurate 3D model rather than 2D schematic. But is it actually that much more work with BIM software like Revit? And is this extra compensated by the benefits of having an accurate BIM for other engineering uses like scheduling, analysis and clash detection?
However more effort is definitely required in the workflow of ensuring engineer's elements are placed accurately where the architect wants them. Is this effect of what the BIM evangelists mean when they talk about "collaboration"?


METHOD 5:
Sub-contractors do accurate BIM.
Sub-contractors provide shop drawings as accurately located and sized BIM. Engineers just provide schematic information.
Problems:

• during design phase effectively the same as METHOD 1. The architect will have to model all engineer's elements to create a useful BIM.
• BIM can't be used for analysis or clash detection before construction starts.
• a lot of design work won't be able to be finalised until construction is under way, leading to possible delays in completion.
• in current practice not all engineer's elements are shop drawn. Power & data outlets, ceiling fixtures are some examples that are not.

Summary:
This method often occurs by default in Design & Construct projects. It is workable, but defeats the purpose of building a complete virtual building before construction, one of the benefits of BIM.
It is also a method advocated by IPD; engage contractor and sub-contractors during design phase so they can contribute. Besides the issues that early selection and engagement of this group entails, it relegates engineers to the role, at best, of advisor, at worst, no involvement at all.

CURRENT SITUATION

This problem can not be unknown to the software developers. Revit's solution is a 'copy/monitor' functionality. Objects between different discipline Revit models can be copied, and then monitored for changes. So this is a type of METHOD 3; Elements are duplicated by different authors but each version can only be used for specific purposes. But it is only a partial solution. There is no direct way to allocate duplicate objects to different purposes in an aggregated or federated BIM model. The other problem with it is the sheer amount of data. For example it is not practical in Revit to monitor thousands of electrical and data outlets or ceiling fixtures found in even moderately sized projects.
Another issue is that a lot of engineers don't see the benefit of BIM to them. I believe one of the reasons for this is due to the slow take up of BIM for analysis by engineers. One of the drivers behind developing BIM for Revit structure and MEP was to use the same model to communicate a design and to perform the various analyses required to inform that design. You would think the advantage of not having to create a new model for every different analysis would drive BIM within engineering offices. But the reverse seems to have happened. Most see Revit as another model they have to do in addition to their analysis models, and treat that model as a drafting tool for doing drawings - schematic drawings.  

I've been involved with projects where all methods but METHOD 2 have been used. It generally depends on how BIM proficient the engineers are and what their client service agreements stipulate. Because, at least in Australia, the client engages engineers rather than the architect, the architect has no power to dictate what they do so we just have to go with the flow.
So no method is ideal, but which one should we strive for?

WHICH METHOD IS LEAST WORST?

Firstly I'd like to emphasise that the list above is not exhaustive. I'm sure others have alternatives they have thought of and possibly used. The other point is that there may not be one method for all situations and projects. But it would be nice if there was.

A word about METHOD 5. It is the one advocated by BIM evangelists. But it fundamentally changes the type of service a consulting  engineering firm provides. Perhaps the work lost to sub-contractors could be picked up by working for those sub-contractors, but it still diminishes the role of engineering consultants. Read my view on the effects of IPD on architects in my post Integrated Project Delivery: Bad News for Architects?

As an architect I'm torn between METHODs 3 & 4. METHOD 3 allows me to hurtle forward doing my work without having rely on other offices, but METHOD 4 ensures BIM data is properly coordinated. METHOD 3 means I have to ensure my duplication work matches the engineers, METHOD 4 means I have to ensure the engineers work arrives in a timely manner.
On balance I think I prefer METHOD 4. It is the proper way to do BIM. Unless I can get that hybrid of METHOD 2 working.

What do you think?

It's OK to not do BIM

In my last post I made the accusation that the term BIM had been hijacked. After reading the comments in the LinkedIn posts I created, (see BIM confusion in BIM Experts group) I have to admit that the hijackers have got away with it. Besides the usual BIM evangelists reiterating their definition of BIM, comments from real users showed acceptance that the meaning of BIM has changed. It seems consensus is now that BIM describes the whole process, not just authoring processes.

I'm OK with that. My aim is to promote practical BIM, and if it is practical to accept a new meaning of BIM I'll go with it.

But if BIM means all BIM processes, then no-one could possibly be doing all of it. Which means no-one is actually doing BIM. So what name should we use to describe the BIM process each of us is doing?

Virtual Modelling

The term Virtual Design & Construct (VDC) is mentioned in the Wikipedia entry for BIM.  I read VDC as meaning BIM for the design and construction phase of a facility, separate from life cycle, facilities management and other BIM uses.
I find this term attractive because it includes an under emphasized aspect of BIM, a description of the technology, virtual modelling.
VDC sounds more like a process, which makes it clearer. One of the problems with BIM is that it can (and is) read in two ways, a process - Building Information Modelling, and as a thing - a Building Information Model. (hence the redundant term BIM model). To add further confusion there are those that propose BIM should stand for Building Information Management, or the real die-hards, Building Information Modelling/Management (BIMM).
But is VDC precise enough? If you are an architect or engineer VDC is not that definitive because you are doing the design part, not the construction part. And are you doing a process, or are you part of a process?

This is not new, so I don't claim authorship, but I propose the terms Virtual Design Model (VDM) for architects and engineers and Virtual Construction Model (VCM) for contractors and shop detailers. All of who are using a Virtual Design Construct (VDC) process.
Bring in a Virtual Life-cycle Model (VLM) , a Virtual Facility Management Model (VFM) and other V_M participants, then you have a Building Information Modelling (BIM) process.

But where is the Building Information Model? What is a Building Information Model if BIM covers all processes? Could it really literally be one humongous computer file containing everything ever done about a facility? Although technically possible in theory (and one of the fantasies of BIM evangelists), in practical terms not a reality. Therefore BIM, as in a Building Information Model, is a theoretical construct, not an actual physical thing; the name we use when all the different Virtual models created for a facility are talked about as a singular concept.

Why is a clear definition Important?

Having a clear description is important to describe to others what you do, and just as importantly, what you do not do. One our current problems is that when you say you do BIM to someone, they assume you are doing what THEY think BIM is. And as BIM now means all of BIM, you shouldn't be surprised, you haven't been precise enough.

I suggest you tell them:

We don't do BIM, we do VDM (or any of the other V_Ms).

and if you want to sweeten the deal:

Others may use our VDM for BIM, and we'll do our best to make it as easy as possible for them within the limits of the software we use.

What does BIM mean to you?

There has been so much written about what BIM means I hesitate to add any more. Yet there still seems to be an enormous amount of variation about what it means to different people.
People may argue there is already a clear definition of BIM, but the reality is everyone has a different version of that definition defined by their own area of expertise.
Let's start with Wikipedia's definition:

"Building information modeling (BIM) is a process involving the generation and management of digital representations of physical and functional characteristics of a facility. The resulting building information models become shared knowledge resources to support decision-making about a facility from earliest conceptual stages, through design and construction, through its operational life and eventual demolition."

Sounds pretty good. A broad, all inclusive description, it includes the 5 'stages' of a facility's life.
But in deeper discussion about actually doing BIM I'm finding the people involved in those 5 stages have differing views on what is important in BIM implementation, and hence their practical view of what BIM means.
Those involved in operations (FM) believe IFC is quite adequate for BIM and don't realise IFC's inability to capture intelligence makes it useless during design. Those involved in design don't appreciate that creating lists and schedules separate from the BIM file adds to the work load of those involved in construction and operations (FM).

There are also some technical confusions in definitions of BIM. One is the myth of the single shared Model. Technically implementation of BIM doesn't require this. Information about a facility can come from multiple models. Yet the Wikipedia description falls into this trap:

"... BIM enables a virtual information model to be handed from the design team to the main contractor and subcontractors and then on to the owner/operator; each professional adds discipline-specific data to the single shared model."

Another is that BIM is only about information. The American Institute of Architects has defined BIM as "a model-based technology linked with a database of project information". But truly BIM software is capable of more than just information, it also has intelligence. It knows a wall is connected to a floor and ceiling, so maintains that relationship even when that floor or ceiling moves. It knows what duct, dampers and AHU unit an A/C register is connected to.

A third area of confusion is defining BIM as the work processes that are possible, or at least easier, to implement when using BIM. The classic is Integrated Project Delivery (IPD), pushed by many as the 'only' contractual arrangement where BIM can be 'truly' utilized. Yet IPD does not require BIM. In the late 1990's I was involved with a project in Australia done under an 'Alliance' contract, effectively IPD. That project was done entirely with CAD. No-one even mentioned BIM as a possibility, let alone a necessity.


So the way BIM is being defined is either too broad, trying to include the many players in BIM; or too specific, including technical descriptions that don't hold in all situations; or about something completely different, that doesn't actually require BIM at all.


So where is the term BIM come from? What did it originally mean?
I won't repeat what has been covered elsewhere, a good reference on the description and history of BIM is at the Architecture Research Lab.
But I have always thought BIM meant the use of the power of computers to hold information, as opposed to  traditional practice where it is held in various people's heads and scraps of paper (called 'drawings').
I used a similar term back in 1998 to describe a method of using CAD to hold information about a building, Using CAD to Model Buildings. I  called this a CAD Information Model (CIM). Utilising standard CAD meant it was very limited, and being for architects and not computer programmers not very sophisticated. It has only quaint historical interest now, but I still maintain that the base thing we are trying to achieve, before any of the other things, is to use computers to manage and maintain information about a building. The only thing I would add is that BIM also includes the managing of relationships between information, the intelligence I spoke of earlier.

So what does BIM mean to me?
I am reluctant to add yet another definition, but to be fair to my readers I feel I should make a clear statement about what I mean. Here goes:

Building information modeling (BIM) describes the use of digital technologies to create a virtual representation of the information and relationships required to undertake the conception, design, construction and operation of a built facility.

I would further contend that the term BIM only be used for what BIM stands for; Building Information Modelling. NOT integrated project delivery; NOT facility management data storage; NOT life cycle design; NOT work processes; and NOT a single repository for all information about a building.

I believe these are all valid and worthwhile purposes, but let's give them their own terms and acronyms.
Let's keep the meaning of BIM simple and to the point, and stop the confusion.

Where's the contractor? BIM Execution Plan for contractors

To be effective BIM needs to be used right from when a project starts. There are already enormous benefits in using BIM during brief consolidation and master planning. Therefore BIM plans need to start at the very beginning so that work done early on can be utilised later. But current BIM guides assume the contractor is a major party in a BIM plan. Why do these BIM guides assume a contractor is on board right from early conception of a project?

Integrated Project Delivery (IPD) is an attempt to get all the players in a construction project together from the beginning of a project. The theory being, if you can do this, BIM processes for the entire project can be worked out in advance.
IPD assumes enough is known about a project at the beginning to do this. That at the briefing stage, before there is a design, enough will be known to select the best and most cost efficient contractor.
It also assumes the owner is willing to pay for participants that won't be needed on the project (besides this BIM 'pre-planning') for months or years into the future. That's if the project actually proceeds to construction - which many do not.

There is a fundamental flaw in this thinking. The Contractor is rarely around at the beginning of a project.
Yet current BIM guides assume they will be.
I've been in a situation like this. We were meeting to put together the project BIM Execution plan, there was no contractor, yet there were clearly contractor driven BIM processes to be included in the document. The client's BIM 'consultant' wanted to use their take on BIM best practice, even though no contractor had actually done any of it to date. Which would mean the design team would be doing a whole lot of stuff no-one would ever use. When we complained the client wanted us, as lead consultant, to determine what the builder would do, what is 'reasonable' as they put it.
As an architect, I don't pretend to know what goes on in the head of a contractor. We try and detail construction in a way that is buildable, but we can't predict what a contractor will actually do. When we cleverly detail a façade so scaffolding is not necessary, they scaffold it anyway. When we design so components can be prefabricated off site, they make them on site. And this is as it should be. They are the experts at construction. There is no way we could predict what BIM an unknown contractor might require.
So the only alternative is to leave contractor requirements blank until one is appointed. The problem with this is all requirements are integrated in a single BIM plan. When you add things in later it is misleading. For example, 4D (construction sequencing) is left blank. A contractor is appointed and wants to use 4D, so the blank is filled in. Now the BIM plan reads as though 4D has always been a requirement, but of course no-one has modelled to suit 4D. You can't add requirements after the fact.
Which brings us back to IPD.
IPD is being heavily pushed as necessary for BIM because BIM plans (based on current BIM guides) only work if IPD is used as a delivery process.
Do we really have to completely re-engineer procurement processes to accommodate BIM? Why not just have BIM plans that reflect what is possible with current procurement practices. Let's use BIM now, not in some utopian future.
For more on my thoughts on IPD read my blog post Integrated Project Delivery: Bad News for Architects?

THE CONTRACTOR NEEDS A BIM PLAN

One thing I do agree on though, is that the contractor should be part of BIM planning. It can't be the overall project BIM plan because they are not around when the project starts. And it is pointless to totally rework a project BIM Plan done for design after the design is finished. Particularly when construction requirements are so different it would require restructuring the plan, not just 'tweaking' it.

My solution is to have a separate document, a contractor's BIM Execution Plan (BXP) to set out how the contractor intends to use BIM. This BXP would be part of a group of documents that form the BIM Management Plan (BMP).
Read my previous posts on the structure of a BMP, and the other plans, the Project BIM Brief (PBP), Participant BIM Plans (PBP), and the Design Collaboration Plan (DCP).

I've called it the BIM Execution Plan because most lay people, including owners, seem to assume a project starts when construction starts, not when design starts. So to most people the BXP is the BIM plan for the project. And in terms of concrete deliverables it is. The contractor delivers a building and information about that building for future management. How the information deliverable would be provided is covered by the BXP.

THE CONTRACTOR'S BIM EXECUTION PLAN

The contractor's BIM Execution Plan would use the pre-existing BIM plans as a starting point. These plans will provide information about what type and quality of BIM information is available, and in the case of the owners BPB, what is required. If a Contractor has a BIM manual for their own standard BIM processes this would also go into the mix.
Even if the contractual power exists to do so, there is little point forcing the design team to adopt the contractor's standard BIM processes. Most of their work is already done. Getting the design team to redo their work to the contractor's requirements will take extra time, be likely to introduce errors, and be met with demands for extra payments. It is far more realistic for the contractor to utilise what is available the best way they can. That said, there will be be areas the design team can do things differently, but they need to be assessed against what is realistically achievable and the what actual benefits will be attained.

The process to create a contractor's BXP might look like:

• Refer to BPB to define owner deliverables.
• Refer to PBPs and DCP to ascertain receivable BIM  data from designers.
• Refer to contractors BIM Manual for desirable BIM construction practices.
• Work out processes required to turn receivable BIM data into owner deliverables.
• Work out processes that will utilise BIM receivables for BIM construction practices.
• Negotiate changes to DCP, and possibly some PBPs, to help those processes.

WHO IS THE AUTHOR
The Contractor, or a BIM consultant engaged by the contractor.

WHEN IS IT DONE
As soon as the contractor is engaged for the project.
It could be requested as part of the bid process if all other BIM plans for the project were made available to all bidders.

HOUSE KEEPING CLAUSES
Definitions.
How this BXP fits into the overall BIM Management Plan (BMP) as defined in the BIM Project Brief (BPB).
Purpose and uses of this BXP.
Who is author / responsible for this BXP and key people on the project.
Contact information for these people.
Record of revisions to this BXP.
Meeting & review timetable.

BIM REQUIREMENTS
Contractor specific BIM objectives.
Contractor only specific BIM uses.
Sub-contractor BIM Plan requirements (for shop drawings).
Minimum modelling requirements for each discipline & sub-contract, either:
- general description;
- specific description;
- LOD table.
File deliverables and schedule.

BIM PROCESSES
Clash Detection.
Construction Sequencing.
Cost Control.
RFI and Variation (change order) management.
As-Built document creation.
FM data capture.


Like the design team's Participants BIM Plans (PBP), contractors should develop their own standard BIM Manual that can be used to inform BXPs they do for individual projects. It is always better to start with what you want, not what others demand.
But I think it unrealistic to believe this BIM Manual could be used to create every project BXP, as each project will have owners with different BIM deliverables, and design teams with different BIM capabilities.
Perhaps this BIM Manual is hierarchical. A series of stepped scenarios. If we get 'X' BIM information from the design team we can do 'A' construction BIM processes and deliverables, but if we get 'Y' we can only do 'B' processes and deliverables.

But I might be getting a little ahead of myself. I'm an architect, part of the design team, so I have to admit I'm guessing a little bit here about what are realistic construction BIM processes. I hope those better experienced in construction will get more involved in this BIM Plan debate, and not leave it up to us so called BIM experts, and certainly not to the BIM evangelists.

This was my last post on my take on the different plans that should make up an overall Project BIM Management Plan. After setting out the logic and philosophy behind this idea, now to see how it works in practice! If you are giving it a try, I'd be interested in how you get on.

Collaboration or Coercion: The Design Collaboration Plan

There is a lot of talk about 'collaboration' in BIM guides. In my mind collaboration means voluntary co-operation. But the requirements of current BIM guides read as enforceable obligations, more like coercion than collaboration. You WILL provide a model suitable for 4D, you WILL use IFC to exchange data. Where's the love?

Until I started studying the BIM guides out there I assumed collaboration meant the team got together and negotiated mutually beneficial work practices.
We'll create some specific views the mechanical engineers can use to put our model into their Navisworks, if they create some reflected ceiling plan views in their model with the settings we want.
We'll ensure all structural elements are modelled separately (particularly walls) in our model, if the structural engineers will commit to accurately placing (within the millimetre) their structural components.

But I struggle to see where these types of arrangements fit into current BIM guides. If it is the intention to allow for them (and they say it is), why are things that are agreed indistinguishable from BIM requirements and deliverables? Part of the problem is deliverables are expressed as work methods rather than actual deliverables, a topic I explore elsewhere.

My solution is to have a separate document, a Design Collaboration Plan (DCP) to record these co-operative types of arrangements. This DCP would be part of a group of documents that form the BIM Management Plan (BMP).
Read my previous posts on the structure of a BMP, and other plans, the Project BIM Brief, and the Participant BIM Plans.

DESIGN IS DIFFERENT FROM CONSTRUCTION

I call it the Design Collaboration Plan because this type of collaboration occurs during the design phase of a project. To be specific, it is about collaborating to create the Design Intent BIM.
During design a lot of changes happen to the model, and a lot of iteration happens. We start with no building and end up with a design for one.
During construction there are less changes to the model, and those changes are less dramatic. We start with a building design and end up with a record of what was built.
Even on Design and Construct projects where documentation and construction proceed closely together, it is still the design team that is doing all the investigative work in the BIM model. The contractor wants it when it is resolved, not before.
The extent of change during design, and the pace it proceeds at, requires a lot of cooperation amongst the design team. Anyone who has worked on a project where that cooperation was less than optimal will know what I mean.

THE BIM PANEL

Most BIM guides talk about the BIM process being run by a Project BIM Manager, usually assuming they are appointed by the client. Obviously there needs to be someone to take responsibility for things running smoothly. But an alternative approach is a BIM Panel, with a chairperson, or Leader.
The panel would be made up of project BIM managers from each of the design team firms. The BIM Leader  could be elected (or coerced), the idea being that person is the one with the best BIM knowledge and experience. So rather than a Project BIM Manager dictating to everyone what will happen, there is a group of experts making agreements.
A BIM Panel may not always be practical, but either way, dictator or democracy, the Design Collaboration Plan can still be created and enacted.

THE DESIGN COLLABORATION PLAN

The idea behind the Design Collaboration Plan (DCP) is to coalesce the individual Participant BIM Plan (PBP) intentions into a single cohesive document. The DCP will obviously be different to a PBP because it won't contain information that is only relevant to one participant. In fact is should only contain information relevant to cooperation.

The process to create a DCP might go like:

• Agree on project BIM Objectives by reviewing participant BIM Objectives from all the PBPs, along with the owner's from their BIM Project Brief (BPB).
• Agree on project BIM Uses by reviewing participant BIM Uses from all the PBPs,  along with the owner's from their BPB.
• Agree on project Level of Development by reviewing participant Level of Development from all the PBPs.
• Agree on a project File Exchange Schedule by reviewing File Exchange Schedules from all the PBPs.
• Negotiate software specific agreements.
• Review the plan to ensure it aligns with the client's BIM Project Brief (BPB).

 It might take several meetings to get agreement on everything. It might be necessary to renegotiate or add further agreements as the project proceeds. Once a contractor is appointed further changes might be required to satisfy the contractor's BIM requirements. So the DCP is a live document that may be revised quite often.
I'd recommend the DCP be an item in regular project consultant meetings, even if restricted to just highlighting the need to make changes to it (so triggering a BIM meeting). On smaller projects all DCP issues could be resolved at regular project consultant meetings, particularly if people with other roles are moonlighting as BIM Managers.

As with my previous posts the description I offer below is not definitive. The contents and structure of Participant BIM plans and requirements of the BIM Project Brief will go a long way to inform what is required  for a particular project.


WHO IS THE AUTHOR
The appointed project BIM manager or BIM Leader of the BIM Collaboration Panel is responsible for creating the DCP, but the contents of it comes from the results of meetings.

WHEN IS IT DONE
Once all major consultants are engaged for the project. If project consultant meetings are being held then it should be possible to start the DCP.

HOUSE KEEPING CLAUSES
Definitions.
How this DCP fits into the overall BIM Management Plan (BMP) as defined in the BIM Project Brief (BPB).
Purpose and uses of this DCP.
Referenced individual PBPs.
Who is author / responsible for this DCP and contributors from each consultant group.
Contact information for these people.
Record of revisions to this DCP.
Meeting & review timetable.

GENERAL COLLABORATION AGREEMENTS
Project specific BIM objectives.
Project specific BIM uses.
Level of Development of overall Design Intent Model (i.e. all models combined) that matches BPB minimum modelling requirements, either:
- general description;
- specific description;
- LOD table.
File exchange schedule.
Project Base Coordinates.

SPECIFIC COLLABORATION AGREEMENTS
Software Names & Versions used.
Sheet Naming Schema.
Agreed Categories and their uses.
Shared and/or common components.
Views for others to use.
Clash Detection Methodology.

Next post I'll look at the contractor's BIM Execution Plan, the last plan in my suggestion for a BIM Management Plan structure.