Building Information Modeling (BIM) is very powerful, but it does come with a price. Higher levels of model development mean more time involved in creating that detail, and someone has to pay for that time.
The AIA Document E202 (by the American Institute of Architects) is the Building Information Modeling Protocol Exhibit and assigns the specific responsibility for the various project team members in developing model elements to specific levels of development for project phases. This contract document is extremely important in legally determining how the model is developed and who is responsible for different parts of the BIM file. This document is not to be taken lightly and has dramatic impact on both the profitability of the project and liability of the project team members.
The E202 document goes into great detail and is too complex to discuss here in any depth. However, there is one aspect that I want to address that has a huge impact on the cost of developing and completing the model. A portion of the document outlines the Level of Development (LOD) for model elements and who is responsible for that level. Various model elements (such as doors, roofs, structural framing, plumbing fixtures, and HVAC controls) can be modeled to different levels from very basic massing to extremely accurate detailing. The E202 document defines those levels, which are from LOD 100 to LOD 500 for increasing degrees of detail. The document also defines who is responsible for developing the types of model elements to that detail.
For LOD 500, the document states “Model Elements are modeled as constructed assemblies actual and accurate in terms of size, shape, location, quantity, and orientation.” The words “actual and accurate” carry a high degree of responsibility in the amount of detail that is included in model elements. Since LOD 500 contains the most model detail, it has the biggest financial impact of anything in the E202 document and much attention needs to be paid to it.
The LOD 500 needs to be carefully defined and the true ramifications considered. It must be determined what level of development is really required, why it is required, and the financial impact of that level. It is very time consuming and costly to develop model elements to extreme detail, and someone must absorb that cost. Will it be the architect or engineer, the contractor, or the owner that develops that final level of development? If the architect or engineer must absorb that cost, then their associated design fees must be increased to cover that cost. If the contractor is to absorb that cost, then the building will likely cost a bit more to construct.
Will the owner utilize the information that is included in that extra level of detail? If not, is it worth the extra expense to the project. The additional cost for developing a high level of detail is very high and there must be a return on investment for that additional cost.
The various team members must be aware of their level of responsibility when entering into BIM projects, and must determine how they will achieve that level. Many contractors do not have that in-house capability and will need to pay someone to perform that task. The responsible person may need to create custom content for many of the model elements as they may not be available from manufacturers or other sources.
If the owner is in agreement, the LOD 500 does not even need to be specified. If there is not a need for a great deal of detail, then lower levels of development may be used and specified in the document. This option will often yield the best return on investment and meet the needs of the owner. The E202 should be completed using the levels of development that are actually needed for the project.
This document is valid regardless of which BIM software package is utilized. Whether you use Autodesk Revit, Bentley Architecture, Graphisoft ArchiCAD, Nemetschek AllPlan, or Tekla Structures, you must still define the level of development in the E202 documents.
Building Information Modeling is very powerful, but it does come with a price. That price and the return on the investment must be determined prior to project design commencing and the contract being signed. The goal is to make the entire project financially profitable for all parties involved.