How do I show the same set of sequences spawned parallely in a sequence diagram?

Question

Imagine that a program spawns multiple threads to do the same kind of sequences interacting with different versions of objects. How do I model this in a sequence diagram?

Say a thread is being replicated n number of times and this thread then performs some operations with objects A,B and C n number of times. How does one show it in a sequence diagram?

Answer 1

Simply show the spawning of the sub-processes and nothing else in a first diagram. Then create a 2nd diagram showing the details for what happens in one of the threads. Now you only need some textual description (a note) which links both diagrams. Alternatively you can drop the detail diagram as Interaction Occurence onto the lifelines of the single threads.