RECAP: The first part of this post ended with an overview of how roles within the building design and construction industry have changed to streamline the process but with competition for control of the BIM model. This is not control for control’s sake but can be justified in terms of higher quality, quicker response to change and a corresponding reduction in the design and construction phases. All these are good things but owning and controlling BIM model is where the most efficiencies are to be gained and the greatest profits to be made. Is is increasingly common for the BIM model to be controlled by the contractor, and other roles subsumed beneath it, that of architects included.
The large commercial and commercially savvy firms such as BIG in the US and MAD in China have countered this trend by running large offices with in-house documentation and information management. Emplooyees include design teams and construction drawing teams, BIM managers leading BIM teams, and technicians scripting in Revit to translate the design into a BIM model. These practices offer the full range of architect services from the one BIM model that the architects own and share with the contractor and consultants.
This simply isn’t possible for smaller architectural offices and the only hope for their survival in a BIM world is for them to take more responsibility for how those geometries will be interpreted within the BIM model.
Cost and estimation
For many years now it has been possible to assign cost information to building elements to facilitate estimation. Assigning the associated transportation and labour costs would allow a high degree of visibility of overall cost and, by extension, knowing if the construction cost was within budget. Generating and updating an online database of materials and costing information is easier for small offices and small-scale projects where only one person is in control of what information goes into the model. Technically, this is possible now but there is little incentive to do so in design offices.
Cost and estimation is a fundamental ability of a BIM model but unless it’s being used as a tool to compare design options it is likely to remain an add-on used by specialists and not as an iterative design tool in the same way that 3D views are. Estimation functionality is already incorporated into the BIM model but architects don’t design with an eye on it. Even a low Level of Order BIM model could have more-or-less instant feedback showing the cumulative total cost of design decisions. I imagine this as a red bar at the bottom of the screen, continually updating to approach a total known as The Budget. It would be very useful. We all know an inclined steel or concrete column costs more than a vertical one. Every design decision has a cost. Designing with an eye on the budget window and its immediate cost feedback should lead to a more efficient design process, a faster construction process, and better resource management. This is not a question of adding new functions, but using the ones already there but at an earlier stage in order to make better informed design decisions.
It would definitely be a great teaching resource if some clever cloud BIM add-on could instantly calculate the cost of every design decision and return in real-time a total for how much of the budget has been spent. Actually, it’d be a great design resource period. Inefficient planning, unnecessary spans or cantilevers would all become real, as would the hidden costs of cheap materials. Setting a maximum budget would teach students how every decision has a cost, and also instruct in the arts of compromise and integration. It would quantify design decisions and make design stances explicit. People would be able to make informed decisions as to whether a particular design decision was worth it.
This is another dimension of building information that could be more directly interfaced with the BIM package so it can be used as an iterative design tool. With its EcoDesigner Star functionality, ArchiCAD can natively create standard energy simulation reports during the design phase and within the same software. Importantly, these are to the widely recognized ASHRAE 140 standard. This functionality needs to be developed so that, when designing, it is another window open on the other monitor, next to the 3D view window and the cost estimate window. Every design decision has a cost in terms of embodied energy as well as energy performance.
A realtime estimate of embodied carbon would also be helpful.
This is all information that, if provided as instant feedback during design, might not only be less wasteful of time and resources, but might just lead to better design the first time.
Moreover, sharing of information to make iterative design changes less impactful assumes that iterative design changes are always going to be necessary. I’m not trying to make a case for returning some roles and authority to the architect. All I am doing is suggesting that iterative “refinement” of a design after its generation is an inherently wasteful process that could be shortened if more of the design consequences were known at an earlier stage.
The instant 3D view functions as a design tool but it makes use of the core functionality of BIM in only a superficial way. How a component or element looks is information but it is only one type of information. The best future I see for BIM is reminding architects that visual information is only one type of architectural beauty. And that there is virtue to be found in cost performance, energy performance and ecological performance as well.
This isn’t beyond our means but it’s not likely to happen as long as design and construction are separated physically and conceptually in the workflow. This is where the problem lies. We know that an inclined steel column costs more and is more carbon intensive than a vertical one doing the same job but as long we see the inclined column as more exciting, daring, or “architectural” there will not be the mindset to develop this BIM capability and make use of it as a design tool. The use of 3D visualizations as a design tool is developed enough.
We really need to get away from architectural beauty as the decadent display of quantity or quality of material resources, contrivedly complex construction processes and technologies, and the decadent display of design resources such as time or computational power.
The Japanese clothing company MUJI [translation: no brand] has been marketing prefabricated houses online since 2004. There are now four types. Wood House, Window House, Sun House and Vertical House and each has twenty plan variations of different sizes and proportions for different plots.
The 2018 website was more interactive but possibly less useful. People could put their cursor on the red dot and shift it and see the plan reconfigure to the new size and proportions and the purchase price change accordingly. For this first plan below, JPY 19.6 mil. is approximately US$200,000 for a 121 m2 house, including tax but not land.
This is not generative design, associative design or automatic design. The only plan variations are those allowed by the standardized panel sizes and the construction system. It’s not that different from how houses were traditionally built in Japan. Panelized timber construction doesn’t fit our image of prefabrication but it is relatively sustainable and allows a high degree of off-site fabrication and mechanization as well as the economies of scale they bring.
This system for ordering, production and delivery is no different from other systems for the manufacture of other smaller and less expensive consumer products for which design is not fed into the system as a real-time variable but as something that is largely fixed but can accommodate a certain level of variation.
The goal of design then, is to set up a spatial system that allows for controlled variation within the limits of the functionality of the product, the manufacturing materials and the system for onsite assembly and finishing. These variations are more likely to be required because of site, functional or household reasons than because of arbitrary preference. Window House [Fig. ] is so named because the positioning of windows is relatively flexible. This allows a degree of consumer personalization for its own sake, but can also respond to preferred and undesirable views and, in towns as densely built as Japan’s, this is important.