What are the primary goals of creating a building model? Who are the key stakeholders?
The primary stakeholders are of course the client(s). However, it's just as important to take into consideration the community around the building. Historical and social context is very important when creating a building. Respecting the land and the history is imperative to creating a long lasting and effective building. Finding a collaboration between what the clients want while respecting the surrounding areas is the goal. The clients need to feel heard, and that their desires are the most important, but at the same time it's necessary to make sure that the building works with the land and community around it. Buildings are more than just structures, they have meaning. Working with the clients to figure out what they think that meaning should be is the first step to making the shareholders happy.
How much detail should you include in your building model? How do you decide?
I think detail is something you get to develop as you go along. When you're starting out, there isn't much detail you can add because you need the foundation to start. It's a process. You start with the foundation, the walls, roof, windows, stairs, etc. and then as you progress you get to add more detail. It's sort of like baking a cake. You have to make the cake, bake it, let it cool, then you can decorate it. And as much as the decorations may be one of the more fun parts, it's no more important than making sure you've taken your time on the steps before it. Once you decide where a door is going to go, for example, then you can pick out the door and add the details. You don't have to wait until the very end, and in fact I don't think you should, because if you continue to add the details little by little throughout the process, everything becomes a lot more cohesive.
Many door and window manufacturers provide Revit families for doors and windows that you can specify for your building design.
If you find a specific door or window that you really like in Revit, if it's one that a manufacturer has provided then you can get that exact fixture. If a client really likes a door in a design, it's very much worth it for the manufacturers to have paid to have their exact pieces in Revit. It exposes their pieces to the client much earlier in the process rather than after the design is done and they have to go pick out every specific feature for their home/work/etc. It also allows the architects to be able to provide a more concrete design when using Revit, rather than putting in a random door during the design stage and then telling the client "this isn't the exact door we're thinking of, but we can figure that out later." The families that are already provided in the Revit library are very generic. It's helpful to be able to put specialized or more unique pieces into a design because it adds character and makes the building seem more real rather than just a plain blueprint for what could be any building.