What are the principal advantages of using a single building information model of the existing conditions as the foundation for modeling proposed additions or renovations?
- Why not create a separate model for the new proposed design?
By working from an already existing building model, one is able to fully understand how the existing and new building will work together. Combining the models helps all parties involved in fully understanding what needs to be demolished, what needs to be reworked, and the types of structural connections that must be put in place. In a similar manner, if a separate model for the new proposed design was created, the overall “story” and image of the building would not be entirely realistic. By having the two models combined, the actual story of the lifespan of the building becomes apparent. I throught the photo below does a great job of explaining this. Two seperate models do not tell the same story of a building as one model would. This would also be helpful if you were planning on performing a life cycle assessement on the building. By viewing all phases, you can see what materials could be reused and which ended up being discarded to carry almost a cradle to gate analysis of the structure.
What are the principal advantages of using a single building information model of the existing conditions as the foundation for modeling several proposed design alternatives for a portion of the building?
- Why not create a separate model for each of the design alternatives?
The principal advantages of using a singular model to model several proposed design alternatives follows the same logic as creating one model for separate phases does. If you are a client for a project, there are so many decisions to be made that by having all of the alternatives for various designs in one place makes the process of switching back and forth very easy for the engineers and architects involved. Most of the design alternatives end up being decided based on budget and relative cost, so by having all the alternatives in one model, the cost estimate comparison is simplified. This type of comparison could also be beneficial if you were designing a complex or building that had repetitions of the same type of wall, floor, or building element, etc. By having all the alternatives in one place almost serves as a means to parametrically flex or alter one or more of the project parameters. For example, let’s say one unit of a condo complex has brick walls but the owner of the lot wants to see stone walls instead - it is very easy to view all the alternatives and even select one option for one unit and another for a different unit to compare.