To create simulation scripts for the top-level RTL design use export_simulation and provide the simulation fileset object. In the following example sim_1 is the simulation fileset, and export simulation will create simulation scripts for all the RTL entities, IP, and BD objects in the design.
export_ip_user_files -no_script
export_simulation -of_objects [get_filesets sim_1] -directory C:/test_sim \
-simulator questa