You can import and export structural members between Revit and AutoCAD Architecture or AutoCAD MEP.
This lets you take advantage of the particular strengths of each application to enhance the workflows for the architectural and structural phases of a project.
A typical workflow using both applications might consist of an architect creating a model in AutoCAD Architecture or AutoCAD MEP and then passing it on to a structural engineer, who will add the structural design in Revit. After importing the model into Revit, the structural engineer deletes all layers that do not contain relevant information for the structural design and creates levels. Then, using a partial explode of the imported drawing to access vital information about the imported objects, the engineer can use it as a reference to re-create those objects in Revit. The imported AutoCAD Architecture or AutoCAD MEP geometry can then be deleted, or retained in the drawing if the model needs to be exported back to the original application.