BPMN pool in groups cannot use "bpmn" autolayout

Question

I have a small BPMN pool with a start, 3 tasks and one endpoint. When I tried to use the "BPMN..." autolayout I ran into three different behaviors.

1. The pool straight under the root/graph node. Everythings works like expected.

http://dl.dropbox.com/u/22930730/yEd%20examples/1.graphml

2. Put the pool in a group with no other members. The layout engine ignores what row the nodes are assigned to and everything ends up laid out in a straight line.

http://dl.dropbox.com/u/22930730/yEd%20examples/2.graphml

3. Have the pool under the root/graph node with a group as a sibling. The layout engine works but the first row gets it height set to the height of the group.

http://dl.dropbox.com/u/22930730/yEd%20examples/3.graphml

Am I doing something wrong or is this a bug?

Answer 1

Thank you very much for the sample graphs.

Re diagram 2: The BPMN layout algorithm does not support nested pools. As far as I know, pools have to be top-level in BPMN (i.e. diagram 2 is not a valid BPMN diagram). So, I would classify this as "invalid  input".

Re diagram 3: Due to the inherent complexity of restricted layouts (the restrictions being the rows and columns of pools), BPMN layout does not support mixed diagrams very well. (By "mixed" I mean that you have nodes in pools as well as nodes that do not belong to any pools.) The algorithm handles such diagrams by adding an additional invisble column and assigning all free nodes to the first row in that fake column.

Comments

Thank you for your response.

I think I have misunderstood the purpose of the group function. I was using it as a way to have several different graphs in one document.