This function allows you to remove all trim boundaries of a trimmed surface and recovers the original untrimmed surface.
Using the Function:
Select Untrim from the Modify>Surface submenu.
The Untrim a Face dialog appears (see above). Configure the available dialog options as necessary.
Select the face to untrim.
Entire Face – This setting recreates the entire trimmed face.
Outer Boundary Only – This setting recreates only the surface boundary of the trimmed face.
Selected Islands Only – This setting prompts you for disconnected portions of the face to untrim.