002 – Training: Craftsmanship in a Model

Let’s talk about craft for a minute. As a BIM professional working in the AEC Industry, I am fully aware of the belief that computers and especially BIM are bringing about the end of craft and thoughtful design. First of all, don’t make me laugh, a Building Information Model requires a higher degree of craft and thought than hand drafting or CAD ever could. Should you decide to make the transition to BIM, leave your “fake it ‘til I make it” attitude at the door, we don’t want that bullshit here.

That being said, there is a major shortage of craftsmanship in BIM right now. This is largely due to a lack of training on the construction and revising of models. When you teach someone how to build a model out of chipboard, you make sure they know to replace their blade regularly and always use a straight edge. The same concept applies to a Revit model. One must know their tools before they can be expected to create something with them.

So here we are, back to the astronomical role of information in BIM. Any model created using BIM authoring software is going to contain information, the amount of which is driven by the Level of Development that is established at the beginning of a project. However, the accuracy of the information is imperative to model efficiency and appearance.

The elements in Revit are parametric, this means that the relationships between them are defined the by data included in each element. These parameters are what enable us to manage the model and drawings through schedules and tags quickly and easily for the duration of the project. Parameters also affect the geometry of the model in ways that can be difficult to recognize without an understanding of the principals of parametric modeling. As a result the drawings produced may not meet the graphic standards we are used to seeing from CAD drawings.

An example of a parametric error that causes an undesirable drawing result is incorrect wall joins such as the ones seen here.





These are the result of improperly assigned function to the layers within the wall structure. Further information on function of layers can be found here.

Now before you accuse Revit of making things too complicated, think about this. The waterproof membrane on an exterior wall has to remain continuous in order for it to be truly waterproof. The 1” layer of gypsum board on a shaft wall cannot be penetrated and maintain the required 2 hour fire rating. This is Revit’s way of asking, “on a scale of 1 to 5, how important is this layer to the overall function of this wall?”

Craftsmanship is the result of thoughtful attention to detail. Building Information Modeling forces designers to consider the function and purpose of each project element to make a conscious decision in the interest of the health, safety and welfare of the end user.