Creating and Editing Structures > Using the Assemble Tool > Defining Coordinate Systems
  
Defining Coordinate Systems
The Origin CSYS and the Destination CSYS options follow:
Parts—Calculates the Origin CSYS from the objects that will move in the operation.
Global—Calculates the Origin CSYS from global coordinates. (The selected input model coordinate system is the default.)
Select from Graphics Area—Opens the Select Origin CSYS collector.
Define—Opens the Construct Coordinate System dialog box.
The most recently-used coordinate systems are added to the Origin CSYS list for reuse. You can select one from the list.