You can import into Fusion virtual machines that you created with Parallels Desktop, as well as virtual machines using the Open Virtualization Format (OVF).
Fusion can import virtual machines created with Parallels or OVF.
When you import a Parallels virtual machine, Fusion creates a VMware virtual machine based on the original virtual machine. The import process is nondestructive, so you can continue to use the original source virtual machine with the product you use to create the source virtual machine.
Fusion can also import the contents of the Boot Camp partition as a virtual machine, creating a completely new VMware virtual machine based on the partition. This is a separate entity, not tied to the partition like the virtual machine described in Power On the Boot Camp Partition as a Virtual Machine. You can then reclaim the space by deleting the Boot Camp partition, which restores the drive to a single volume.