Can i convert activity diagram to sequence diagram in UML default approach Or i should draw activity, sequence, use-case, class diagram and convert the sequence into collaboration diagrm by selecting model menu


Activity diagrams and sequence diagrams aren’t isomorphic. That is, information in one diagram would be lost when converted to another diagram. You’re probably better off drawing a sequence diagram first. Activity diagrams are better suited for modeling low-level operations. Pick whichever one better conveys the context you’re trying to show.