Tuesday, August 10, 2010

A model progression…?

Here’s one to contemplate: How do we construct models that allow us to leverage the efforts of those that have used the model before us and increase the information in the model without losing information and keeping the model lean enough to function effectively?

Just because we are using a BIM authoring tool, doesn’t mean that we have removed all of the disconnected silos of information in the project delivery process. When a designer is in the early design stages they must be able to investigate space requirements and form fluidly. At some point they need to turn focus to constructability. That constructability must then be refined and documented. Then the project must be sequenced for construction with resources and tasks added to assemblies. Finally, the model should be prepped for handoff to the Owner (with linked O & M info, etc., etc.) At each of those steps we have the choice to follow the traditional handoff process that produces silos of information, or think (and maybe work) a little harder to craft a way to prevent handoff and tear down the silos.

Rarely will a resource tasked with creating CDs be able to use the same objects (such as walls) that were used at the SD and DD stages of the project. Similarly, it is uncommon for a GC to take a designer’s model and be able to use it to investigate constructability or arrange the information so it may be used for sequencing. Often the previous work is used as a template to create a whole new model in a separate file. Not so far from the silos of the “past.”

One of the AIA’s tools for IPD (Integrated Project Delivery) suggests that we add detail to the model as we go, using their Model Progression Spec (which you can download here.)

The MPS (Model Progression Spec (I swear, it really is always a TLA (Three Letter Acronym)) is a great document and provides a lot of guidance on what should be in a model.

from Vico's website

However, it lacks a definitive when. When an object should be “upgraded” to the next LOD (Level of Detail (told you, TLA.) I think the when almost needs to be decided on a project by project basis, but working backwards from a complete model and indentifying who needs the highest LOD (at this stage of the project) and the latest they can possibly receive it, will help you set deadlines. If you then work forward through those deadlines and find the earliest possible time you can make the decisions required to up that level of detail, you will be well on the way to having a workable Virtual Building modeling schedule. I know that’s just Critical Path Management (CPM (there’s another one) but you’d be amazed how everyone seems to throw out everything they have learned about delivering a project when “push come to shove” while learning a new tool/process. So let’s get back to some basics.

Vico Software also has some suggestions and examples of how to use the MPS (as well as something they call a content plan) when building a model. It’s worth looking into.

Anyway, my inspiration to write this post is to offer some suggestions about how you might add detail to your model without having to rework effort that has gone before. Since this has gotten kind of long, I’ll leave that for next time.

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