Modeling Guidelines for SysML Activity Diagram

The activity diagram is used to describe the flow of control and flow of inputs and outputs among actions. OMG Systems Modeling Language (OMG SysML™) Version 1.6

SysML Activity Hierarchy Diagram

Enterprise Architect provides a type of SysML Diagram called "Activity Hierarchy":


As described in Enterprise Architect documentation, Activies are classifiers that allow usage of associations between them through relationships as Compositions or Aggregations. Activity Hierarchy Diagrams offer facilities for drawing Activity decompositions and relationships.

Based on this definition an Activity Hierarchy Diagram is not an Activity Diagram even if depicted with an "act" prefix as Diagram Frame, and is considered as a Block Definition Diagram when published to Magicdraw.