For the onion shaped dome start by using the model line tool to trace the shape from a photograph.
How to make a dome roof in revit.
For glazed domes based on curtain walls only the second does.
Autodesk revit out of the box has an array of different primitive shapes including dome.
Get this revit file here.
First bring in a mass family from the library.
In this video i show you how to model two types.
For both domes create an in place family by choosing component model in place and then choosing roofs in the family category dialog box.
1 new family generic model from a front view create solid revolve draw the section select an axis finish load into project roof by face select faces finish roof.
For the simple curved dome use the revolve and axis line tools.
This video shows how to create two types of domes as in place roofs in revit.
2 for glazed domes.