I just started to evaluate ARIS Cloud and I am not able to find a way how to place a collapsed pool in the BPMN 2.0 collaboration diagram. It is in the BPMN 2.0 standard, so there should be a support for this element in ARIS Cloud, right?
I even tried to use a simple rectangle instead, but that won't allow me to connect it with message flows.
Is there a certain trick/a hidden menu, where I may change the pool into being collapsed?
I am not aware of a BPMN feature of "collapsed" pools. You can collapse and expand sub-processes, such that the subprocess flow shows in the subprocess symbol or the subprocess symbol shows a "+" in a square when collapsed.
There is the concept of modelling a process in a Pool, which is often called "white box Pool", or not showing any content of a Pool, called a "black box Pool". It is good practice to show only one white box Pool in a single model and depict all collaboration partners as black box Pools. Is that it, what you intend?
Then here is what you do: Model your white box Pool A and create occurrence copies of Pools B, C, D... that A collaborates with. Simply leave them as black box pools. You should resize them to become a lot smaller than your white box Pool, so you can comfortably model the message flows to and from the other Pools and arrange them around Pool A.
Model each process B, C, D... in one collaboration diagram each as white box Pool. Make sure to use occurrence copies of the objects you showed in the Collaboration Diagram A. This makes consistency checking a lot easier. Suggestion: Use the assignment feature to assign the collaboration diagram to the Pool it depicts as white box pool. Then you can navigate from the black box Pools via the assignment symbol to the corresponding Collaboration Diagram explaining that Pool in detail. This is probably the effect you want to achieve with "expanding" your "collapsed" Pool.
For a consistent overall model you have to check, that a message flow from A to B shows in both Collaboration Diagrams for A and B. If you use message flow envelope symbol on the message flow it is good practice to use occurrence copies of the envelope in both diagrams where the message flow is shown.
