The UAF Operational Processes: Activity Decomposition viewpoint is a diagram upon which you can specify the decomposition of OperationalActivities. In DoDAF 2.0 this was the OV-5a Activity Decomposition viewpoint, and in DoDAF 1.5 was called the OV-5a Node Tree viewpoint.

In System Architect, you connect an OperationalActivity to its parent by moving it underneath its parent until an autoconnection is established – the definitions are updated and the relationship line is automatically drawn.

You can change the way the hierarchy is displayed by right-clicking on a symbol that has child symbols, and choosing Arrange Children Horizontally, Arrange Children Vertically or Arrange Children as a Block.