What are the primary goals of creating a building model? Who are the key stakeholders?
By creating a building model, the design of a structure can be made and easily altered in CAD before constructing the whole structure. The building model helps show the dimensions and shape of a building in the intended environment, showing architectural, structural, MEP, and other interior objects and how they will work together. It is overall a great coordination tool for different people on the project. The key stakeholders are the ones paying for the structure’s design/construction, and the people who will engage most with the structure. The paying stakeholders may take the cost into most consideration, and want to make sure the building is designed efficiently. The structure model can help estimate the cost of material and labor. For the stakeholders using the structure, they may care more about the flow of the room layout, or overall architectural look.
How much detail should you include about the composition (layers, materials, thicknesses) of your wall, floor, and roof assemblies at different stages of your design process?
At conceptual design, the most general details with the structure dimensions are most important. This can help visualize the intended size and purpose of the structure. Nothing specific about the structure material needs to be set in stone.
At preliminary design, more details regarding wall/floor/roof thicknesses should be included. Here, the design of the structure will be sent for feedback from the stakeholders, so enough detail needs to be given to show the building intention. Material of those components would also be good at this point.
With feedback, the design can be further developed until the model is at its final phase. Here, the intended material, thickness, and layers the structure component should be fleshed out more for final approval.
Finally, at construction documentation, the details of the building structure should not only be developed, but also communicated through construction documents. This will ensure the design is properly constructed to the exact intention.
Many door and window manufacturers provide Revit families for doors and windows that you can specify for your building design.
When manufacturers provide Revit families, they are basically marketing for designers to use their products. The manufacturer can provide the exact dimensions and overall look of the doors and windows, which the architect can use to visualize their exact design. When the structure is actually being built, the the manufacturer will be able to profit off of selling their product. As a designer, you can consider that the manufacturer provided families are specific items on the market that can be bought, and not an arbitrary sized object in the Revit drawing.