You can create 3D views of:
the whole building,
a floor of the building, or
a cropped view of part of the building.
You can also duplicate an existing 3D view.
To do this refer to CREATE A COPY OF A VIEW or SCHEDULE
3D VIEW OF WHOLE BUILDING
Under View tab, select 3D View, then Default 3D View.
This will create a view with a name of {3D - username} e.g. {3D - Barry.Hayes}.
If a view with this name already exists that view will be opened instead of a new view created.
The view can be renamed by going to Properties window and editing the View Name parameter.
If you intend to keep the view rename it with an X- prefix and your initials (e.g. X-BH_overall).
Also change Sheet Series.SH parameter to working.
3D VIEW OF A FLOOR
Create a new 3D view as described above.
Click on the triangle next to the view cube.
In the menu list select Orient to View, then Floor Plans.
A list of all floor plans is listed, select which one you want to use.
Generally select a General Arrangement Plan.
A 3D view is created looking from the top. Click on a corner of the view cube (top right corner) to orientate the view.
A Section Box is around the building. Select this and blue pointers appear. Pick any of these to drag the extent of the section box.
Rename the view to describe the floor it is showing.
3D VIEW OF PART OF A BUILDING
Note this only works in Revit 2016 and later.
In any view (plan, section, elevation, detail) select an object, or objects, in the area you want to see in 3D.
In the Modify menu (which will be active once objects are selected), in the View pane pick Selection Box.
A cropped 3D view will be created.
If you select the Section box control grips will appear that can be selected and stretched.
After stretching:
The view created will have a name of {3D - username} e.g. {3D - Barry.Hayes}.
If a view with this name already exists it will be replaced.
If you want to keep the view rename it by going to Properties window and editing the View Name parameter.
Rename it with an X- prefix and your initials (e.g. X-BH_bath tub).
Also change Sheet Series.SH parameter to working.