Using BIM in the Earliest Design Stages

One of the common misconceptions among architects regarding BIM is a perceived need to wait to use it until a design is advanced and ready for construction documentation. To do so eliminates some of the best and creative aspects of BIM and denies its real time-saving potential. Instead, design can begin from the outset using BIM. This is possible because the fundamental tool used by computers is parametric design, meaning that parameters such as geometry, form, or other conditions determined by initial programming and feasibility data can be entered into the computer as design conditions. This can be done in words and numbers in addition to spatial guidelines and dimensions since computers bring new powers to designers to create their own parametric objects through what has become known as graphical scripting language. Based on these parameters, the computer can generate a 3D model consistent with all of the design inputs. This approach is also called generative design based on the ability to create or generate numerous options by changing one or more of the defined criteria or parameters of an initial design. In this way of working, design intent comes first while digital tools become the means through which an architect brings exploration and resolution to that design intent. Of course conceptual designs can be still be initiated with a basic model or even a hand sketch if preferred, which becomes the basis for the design parameters.

Part of the beauty of working with BIM from the outset is that it allows total flexibility when making design changes or alterations as a design is refined or as feedback is received. The process is streamlined since in a parametric environment, elements have a hierarchy and a relationship to other elements. That means changing the length of a wall for example, would update not only the wall but also any elements within it such as framing, windows, insulation, etc. In this way, BIM supports a real iterative design process, easily allowing changes in a model and leading to a progressively deeper and more comprehensive understanding of the building being designed. This streamlined approach is helpful since it is common for any design process to generate a lot of changes or alternatives at the beginning of the process and hopefully less as work continues. If cardboard models were being built or paper or CAD drawings were being prepared to look at all of these variations, it would be very time-consuming. But with BIM, a base model can be created and then saved as a separate file to create a variation, which can then be saved to produce another variation, etc. This process is much more time-efficient and allows solutions and variations to be produced and investigated rapidly. Using BIM at the outset also means that all of the variations and alternatives can be saved as separate files so each one can be captured, studied, and compared to the others.

Images courtesy of Nemetschek Vectorworks, Inc.

Using iterative modeling as the basis, BIM can be used at the very beginning of the design phase to look at fundamental massing and siting issues of a building.

The level of detail in an early design model is also completely definable. The model can focus on just the exterior shape and form just as a massing model or study model might have in traditional times. It can go a little deeper and look at the building envelope in terms of glazing and façade treatments. It can look at interior spatial volumes and areas as they relate to each other and define the flow of interior spaces. It can model existing conditions in a building renovation project. Specific areas of a building or project can be isolated and explored in greater detail if needed to inform the larger overall design. Hence, the design process remains fully personalized and fully adaptable to the size, scope, and criteria of the particular project. In short, anyone who values design should value the potential of BIM.