In my last post about the urgent need to standardize BIM element properties, I promised to help do that. Here I begin to present the classification system for property names that I’m developing. I list my proposed 1st (entry) level of classes. Then I give an example of how they can be used to arrange tailored sets of information (SOIs) for the different actors involved in a project.
A key goal is that the system be clear and easy to understand, “human-readable”. Since the purpose of BIM, I’m convinced, is “to give each actor just the information they need at just the right time throughout a building’s lifecycle.”
So let’s look at entry-level classes – the first of the three letters in the code for identifying each specific property. You’ll see that each class has its own purpose, which is briefly described.
Now consider this simple example of how to use 1st (entry) level classes in an EIR, AIR, BEP or PIM for early-stage setup of SOIs (sets of information) for a ventilator:
[NOTE: This is only an example for explaining how to use SOI. You should set up this type of matrix yourself for your own projects. Don’t use this one.]
With a matrix like this, it’s easy to determine what GR (level of detail) is needed for BIM objects.
We see here that the 3D model of the ventilator is mainly needed for clash detection, design authoring, logistics planning, as-built records and building maintenance. In that light, let’s look at the needs of specific BMI actors:
A BIM Manager only needs the ventilator’s precise external dimensions for an accurate interference check report. He or she doesn’t need a hi-detailed 3D model, just the external dimensions.
A Transportation & Logistics Planning Specialist needs the approximate size of the ventilator to plan loading of the truck.
A Contractor will need rights to modify the location and dimensions of the ventilator for as-built records, in case on site those things change during construction.
A Facility Manager needs the precise external dimensions of the ventilator in case it has to be replaced.
An HVAC Engineer needs to create the 3D model of this ventilator, to correctly represent it in the BIM model in a way that satisfies his needs and those of team members.
Thus we can draw the conclusion that GR1 is appropriate at all BIM stages!
Recall that what’s of value for getting the benefits of BIM is not achieving some general level of development for a model, but rather detailing specific elements and assemblies at a level appropriate for what you want to do with those BIM objects. The 1st level classes for BIM object property names help us to achieve that.
Looking forward, my intention is to look in detail at the sub-classes and specific properties that each one contains. As the matrix above shows, class “I” (Identification) is the most important property set. In the next post, then, I’ll begin by looking more closely at the Identification set of properties.