Mark Robison, P.E.

Summary: Introduction to the concept of Building Information Modeling in contemporary engineering.

In the visions of the future, 3D-BIM starts at the concept phase and is carried through to the construction documents and beyond. That is the future, perhaps. For today, we still “design” using a range of tools including arm waving and architectural flimsy, you know, that tracing paper architects always have. I recall watching an architect working with a client over a set of plans. The architect grabbed some flimsy and drew a rectangle, laid it on the plans, and asked, “A room about this size?”. He then tilted the room at an angle and exclaimed, “In fact, this is how it should be”. The client nodded in concurrence and the design process continued.

Someday the computer will be as fast as flimsy, but it is not there yet. But as the design moves from flimsy to CAD, the process turns from “design” to “construction document” creation. And at some point it is appropriate to add detail to the elements toward being a 3D-BIM. I’m sure the creators of Revit and ArchiCad would cringe to hear me say anything but that the process should begin immediately, but that is why we have blogs, so people like me can share real life experiences.

The fact is that there is still both a culture of transition and a practical basis for that culture that does not match full 3D-BIM at the start of a project. I don’t think anyone should apologize for this condition. Don’t be thinking that you are somehow failing to keep up with technology just because you find it easier to think in stages. The human mind can only solve so many problems at once. In fact, don’t we often teach the concept of breaking a tough problem into smaller, easier problems, and solving each one separately. So rather than trying to think of door swings and egress path lengths at the start of a concept design, an architect draws big mass blocks and space planning diagrams. The door swing and lock set details would just get in the way of some really challenging issues. Likewise, working in 2D removes one dimension from the problem during a system layout. The third dimension can be added later after the engineer has the plane solution figured out. When you think of it in terms of dimensions, and time being the fourth dimension, you would never try to solve all four dimensions simultaneously. The fourth dimension is called “means and methods” for the contractor, and engineers are not suppose to address that issue. Of course, at some point it is good to think about that dimension, because sequence is of huge concern to the contractor. But even within design/build contractor organizations, there is generally a separation between the design phase and the shop drawing (third dimension) phase. And then further separation between shop drawings and project sequencing. (fourth dimension)

This entry was posted on Wednesday, October 8th, 2008 at 2:26 pm and is filed under 3D-BIM. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.