Let’s draw the following activity diagram. This activity diagram is taken from “Figure D.38 – Detailed Behavior Model for “Provide Power” (Activity Diagram)” in the SysML 1.5 specification.

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Activity Diagram

  1. If you are starting the tutorial from this page, you can download Astah SysML and a sample file which contains all the diagrams throughout the previous chapters.
  2. Right-click on the “PowerSubsystem” Block in the structure tree, then go to [Create Diagram] – [Activity Diagram].
  3. Then a blank Activity Diagram will open in the diagram editor.
  4. Let’s rename it as “PowerSubsystem Activities”.
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Creating Partitions

Activity diagrams are easy to understand because they represent the flow of operations in a diagram similar to a Flowchart diagram.
First, let’s create all vertical partitions. Click on the “Vertical Partition” button and click on the diagram to place the vertical partitions.


Rename one “pcu:PowerControlUnit”, then “pcu:PowerControlUnit” and”epc:ElectricalPowerController” partition.

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Creating Objects

From here, we can create Actions, ObjectNodes, and Activity ParameterNodes. The creation process is the same as for Blocks and UseCases, just select the respective tool button and click on the desired location.

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Actions

You can create Actions by selecting “Action” on the tool palette or by directly double-clicking on the diagram.

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Object Nodes

Blocks (base blocks) for ParameterNodes can be edited on the diagram or in the properties view.
Also, add the “continuous” stereotype to both “accelPosition” and “eThrottle” blocks. You can do so by selecting the block in the structure tree first and going to the Stereotypes tab in the Properties View.

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Activity Parameter Node

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InputPin

Let’s create an Input Pin
Select the “Input Pin” tool button and click on the a1 Action.

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ObjectFlows

Let’s connect each item with an arrow that represents the flow of motion.
Select the Object Flow on the tool palette and click on the two items to connect.

Once you get familiar with the mini icon that appears when you have a mouseover an object, it’d be much easier and faster to connect items by using that.

You can download the file that contains this Activity Diagram from here.

→ Move to Sequence Diagram