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?
Having design alternatives in a single BIM model is mostly for ease, as you can add layers of design alternatives instead of copying the model multiple times. Additionally, if there are many structure/shape changes, only the single BIM model would need to be updated, which will update the design alternative background automatically. This is quicker than having to make the change across multiple BIM files.
This is also easier for sharing documents. One BIM model is easier to show and share with multiple stakeholders, instead of confusing them with multiple models. The clearer the communication model, the easier collaboration is.
In your project, which features of the proposed design did you choose to model as design alternatives?
I decided to change the furniture layout of the dining area. In one option, the dining area consists of 3 large dining tables and a few, small dining tables scattered in between. In the other option, all tables were medium sized, spread throughout the dining area. Depending on the layout, the way people walk into the building, or to the stairs, may change, and may be more or less convenient. The different table sizes also encourages larger group collaboration if needed.
The most difficult part was trying to figure out how the 3D views can be input without showing a different design option. Eventually, I figured out that the primary design option will show in the regular model, and therefore in all of the other design options. I also struggled to decide how I wanted to layout the dining area. In the future, I would add some sofa/coffee table areas for more variation in seating