When opening a project in AC15, all Viewpoints, including the 3D Window, default to the "Existing Construction" Renovation Filter. This is frustrating, as the first time you open the 3D Window after opening a project, the window is empty (unless you have existing elements). This can be avoided in other Viewpoints by working in saved Views, but I still find it frustrating.
If anything, Viewpoints should default to "New Construction", as we more-often-than-not wish to view the current state of the model.
MacBook Pro Apple M2 Max, 96 GB of RAM
AC26 US (5002) on Mac OS Ventura 13.5