Identifying the Difficulty of BIM (3) – Definition of Information
What information do we want to extract from BIM?
To put it in an extreme way, this answer will be nothing but a quantity. People might say that the consensus building and the crash detections with 3D view are also the purposes of using BIM. As a matter of course, three-dimensional drawing information is also one of the important information, but the consensus building and the crash detections are also means for producing confirmed information. What we want to achieve is “getting the confirmed information” of the results agreed upon by the concerned parties in the model.
For the usage of this “confirmed information”, there are cases where three-dimensional model information is required, but here we consider it as a one-dimensional “quantity”.
From BIM, we can obtain the information such as cubic meters of concrete, square meters of gypsum boards, number of single-swing doors. We can obtain thousands of types of component data from a fully equipped BIM. We can obtain the “volume” from all model elements, the “area” from all surface elements, and the “number” from all components. However, in many cases, creating just a model does not achieve the goal. This is because thousands of numerical data input have no value unless they have the specific meaning in each.
Numerical data will have a value as an information only when it is combined with “what is” information. In the example above, the “subject” is necessary such as “cubic meters of concrete is,” “square meters of gypsum board is,” and “number of single-swing doors is”. Then how can you decide this “subject”? Is the “subject” “cubic meters of concrete” sufficiently representing a set of the meanings? Is it necessary to define with subdividing the concrete into “concrete of Fc21” and “concrete of Fc24” considering the designed strength? Or is it necessary to define with subdividing the concrete mix detail in consideration of the time when placing an order for the concrete mixture plant?
The answer is “indefinite”. All the detail definitions might be necessary, but none might be necessary. The answer depends all on the project organizational form, the objectives of BIM in the project, and the phase of the project, etc.
The fact that there is no method for this creating data is the third aspect of the difficulty of BIM