In iClone, the Link function is now enhanced. You are allowed to link your object to another one at a specific point of time and then unlink it at another time.
The Attach method allows you to combine objects into one piece while the individual sub nodes are still available for modifying.
Basically, the Link never changes the Hierarchy Structure of the current project while Attach does change the structure unless you detach a combined object.
Initial structure |
After Link (Structure remains) |
After Attach (Structure changed) |