Building Information Modelling - Accept No Substitute
The SIX AD operations pipeline fully utilises Building Information Modelling. We avoid other design methods at all costs; this is why...
Introduction
In 1995 I began a year in practice at Atkins Consultants, at Church House in Middlesbrough. I'm grateful that my training began with learning the traditional craft of technical drawing on a counter-balanced board. It's a good starting point for all architecture students, as you get in to the practice of considering the need for every line that you draw, one, because every line communicates something and two, because you physically have to scratch out every eroneous or obsolete line with a razor blade.
I started my life in practice at a time when 2D Computer Aided Design (CAD) was becoming more prevalent in drawing offices. The benefits have been long debated. The ease with which elements can be repeated. The speed with which you can delete or trim lines that you no longer need. The wonderful layering sytem that was the key to managing complicated drawings - oh, if only office standards were firmly established and enforced.
I submitted the thesis for my Diploma in 2004; in it I predicted that there would come a time when we no longer physically rented DVDs, we just downloaded films; when ICT was seamlessly integrated in to building components to give us real-time feedback on temperature, wear and tear etc; when virtual reality would be the medium by which we design.
In universal terms, a relatively short time has passed, but the download / streaming prediction was realised some time ago. How long before the technology of 3D TV develops to provide greater immersion and then converges with our design software so that we design buildings from the inside out, rather than the outside in? How much longer until we can acheive more virtually than we can physically and by concession and default, we fail to recognise our own transition in to 'The Matrix'.
Personally, I'm happy that the days of simple lines in 2D CAD software is gone. Building Information Modelling (BIM) is reality now - the technology that I dreamt of in my City & Guilds AutoCAD class in 1995. BIM is what I've been waiting for. Finally we have a tool that allows us to develop working models in parallel to advanced visualisation; now designer, client and end-user are all able to talk the same language. It's visual.
But it's also considerably more than that. If you sweep aside the presentation options that BIM inherently offers, you get to the crux of what BIM is about. Building Information Modelling exists to embed intelligence in to our design projects. It offers an opportunity for all parties involved in a project to be on the same page.
With a heightened level of collaboration, we can rapidly explore design options, refine improvements and reject wayward experiments. We can also have a much higher degree of confidence that what's on the screen is what will be built on site. Office standards are implemented by the software rather than the operator, which means consistency in output; that in turn means that sharing data and digital objects is easier. Why has this taken so long? Why is BIM still being resisted?
From day one, SIX AD has exclusively utilised Building Information Modelling to develop our projects and evaluate and refine them 'on the fly'. We're going to look at SIX reasons why we use BIM. It just so happens that these reasons overlap with the SIX Principles that our practice is founded on.
Design
The design advantages of BIM are immediately apparent. We live in a 3D world, a world to which we relate through perception of depth. Some of our clients struggle to interpret the 2D plans that we generate from our 3D models; for that reason we prefer to issue perspective images of our design schemes to accompany the layout drawings, as they quite literally add an additional dimension.
In drawing in 2D, the design process invariably involves modifying or erasing elements in order to refine and develop the design. Wherever this occurs, there is an argument that design time has been wasted, although from an alternative perspective, each change moves the process on towards its final goal.
With the BIM approach, the whole model is available for editing at once and is in a constant state of refinement. This allows the designer to start with a concept and work through the model in a rigorous and methodical manner, rather than be constrained to working in one view of the building before moving on.
This means that ‘rough’ views of conceptual masses can be produced at a very early stage in a project, which allows for collaboration to be in effect during those preliminary phases; clients feel that their opinion is having an impact as feedback from all parties immediately informs the design process.
Integrity
In terms of BIM, integrity in this context primarily describes ‘integrity of intent’, although it also applies to data integrity and design integrity. BIM requires collaboration between all of the design partners and related parties. Transparency between organisations is critical, as the free flow of project information between consultants is critical if all project partners are to work on the most up to date information. This approach requires a commitment on behalf of all consultants to ensure that their data remains current, otherwise the efforts of project colleagues may be wasted.
Ultimately, the integrity of intent can be refined to a few sentences. In adopting a BIM approach, we’re not just trying to do the minimum to complete the project and claim the fees. We utilise BIM because it gives us a greater degree of freedom to design, but also because we want to understand and quantify the challenges, so that we can produce solutions before they’re needed and share those solutions with the wider team.
Flexibility
A BIM project is able to remain open to revisions for longer than a 2D project because of the fact that the BIM project file is essentially a database, rather than a group of unrelated lines on a series of drawing sheets. BIM software knows that when a wall is moved in plan, the same wall needs to be moved in the section views too. When the roof height changes on the East Elevation, all of the other elevations need to be updated accordingly.
When a deadline is looming and a change is requested, in 2D drafting the onus is on the operator to ensure that all drawings are updated and no conflicts are created with existing elements. With BIM, the model is updated in one view and updates in all related views in real-time; the software feeds back any warnings on potentially unseen problems caused by the amendments – this gives the operator the opportunity to rectify and overcome any complications in the model.
The BIM project also offers the flexibility to have several related design options embedded in the same model and available for evaluation. Gone are the days where we would have had a separate file for each option, which always opens the project to risk of revisions not being carried through to the final design option. This presents a much more robust way of working.
Knowledge
In practice, we found that the knowledge required to operate our Building Information Modelling software had a steep learning curve, but it levelled fairly quickly. In reality our BIM software is relatively intuitive and many of the functions for various model components are similar and therefore a level of familiarity was rapidly established.
The BIM approach to design development is certainly most rewarding for those that are confident in building construction and already have a strong sense of what they plan on achieving. The converse is also true, that the BIM software will also guide those with relatively little construction knowledge.
The model quickly begins to provide feedback that informs the design process. This amalgamation of thought process, design intent, concept development, design development, detailed design and so on, is all the more powerful because the BIM approach allows the design sequence to be non-linear if necessary and provides a continuous stream of feedback, as frequently as the operator moves between commands, or changes views.
Efficiency
The overall advantage of all the previously mentioned benefits of BIM, is that it saves time. The BIM process allows the operator to achieve this in two ways. The first, reducing the user operations required to reach the completed project. The second, in comparison to a 2D workflow, BIM reduces the amount of time needed to make revisions, reduces the likelihood of errors and checks itself for inconsistencies as the model progresses.
An intelligent way that BIM software increases efficiency, is through the database driven management of objects. This means that when the production of a window schedule becomes necessary, the BIM project already has access to information in the model that it can use to generate the relevant schedule. The relationship is bi-directional between the schedule data and the graphic representation in the model; this means that a change to the model will lead to an automatic update in the schedule data and vice versa; this serves to reduce errors.
Parametric data allows for sub-sets, or sub-versions of objects within a single file. This means that in a BIM project, there may be one attached file that provides every door type within the project, even though there may be several different versions of the door used in the model. This parametric approach ensures that file sizes are kept to a practical minimum.
People
BIM provides a toolset that allows for a more informed way of working. Building designers have accepted for years that walls should be drawn as parallel lines and that inserting a door requires us to trim the lines etc. With BIM coming of age, the time taken for an operator to complete those tasks can now be given back to the operator to consider more important subjects, like the design of the overall space and most importantly, the impact of the building on its occupants.
When you pause to review how we’ve been willing to work, the stark reality is that we’ve become slaves to a workstation. To a greater degree than its 2D cousin, BIM places control and options back in to the hands of the operator. This allows the designer to present a half complete model to a client and show live sections and effectively take the model apart in front of the client to demonstrate how the building will work. The clients understand the rough version of what they’re seeing because it’s in a format that they understand. Each iteration of the model becomes more detailed until the final version is reached.
That’s the key to the attractiveness and success of BIM. We live in a 3D world. It makes sense to work with software that works in 3D by default and offers real-time feedback. This is software made by Architects for Architects, but more importantly by people, for people.
Conclusions
As a practice, we’re convinced that the benefits of working with BIM far outweigh working in 2D. Since SIX AD was founded in 2009, we’ve had relatively few projects that were so small, that they didn’t warrant the construction or justify the fees of a 3D model. We’ve had a number of clients say that they’re not interested in a 3D model; when quizzed on the reasons why, it’s usually rooted in a belief that it will be more expensive. When we explain that working in 3D has allowed us to overcome planning objections and shown the client the power of visualisation, they are quickly won over.
Until May 2011, our typical fees followed a more traditional split of 35% to Stage D, 30% to Stage F, 15% to Stage H and 20% to Stage L. Since June 2011, we have been operating a fee structure that is more closely aligned to the work involved in a our BIM workflow, i.e. 48% to Stage D, 24% to Stage F, 12% to Stage H and 16% to Stage L.
In switching from CAD to BIM working practices, it’s important to note that BIM is not simply an alternative way of producing 2D information. It’s a means by which a virtual prototype of a building is produced, with all of the related possibilities for environmental, structural and life-cycle analysis.
In summary, the BIM process requires wholehearted commitment; half measures will yield poor results. BIM is also an ethos to consciously adopt; the design team must be committed to producing a building, not just a series of drawings. KB
Next steps
Autodesk Revit Architecture is the BIM backbone of SIX AD. Find out more about its features as a massing tool, as well as visualisation, design, detailing and scheduling software, by following the link.
For BIM training or software requirements, we recommend MicroCAD.
