A few weeks ago I became aware of the bxModeller from Engineering Ingegneria Informatica S.p.A. and the University of Salento in Italy which is an open source / free tool for BPMN/XPDL modeling. I got access the bxModeller to see how it would perform. It can be entirely accessed on-line. Nothing needs to be installed. That is certainly convenient. You create projects, give them names, and start designing the processes. Later you export the results as XPDL.

I started by designing a copy of the OMG Trouble Ticket scenario (see examples). The result was a respectable diagram as shown below which includes swim lanes and all the standard BPMN elements:

Then I was able to export the diagram as either an XPDL 2.0 or an XPDL 1.0 diagram. So far so good. And I was able to import this into the Fujitsu Interstage BPM Studio. The resulting diagram was correctly connected and could be executed. So XPDL interchange worked. The layout was not perfect in the imported diagram, but that is a common problem among such tools. A little bit of manual moving of the boxes around and the result was a perfectly usable model.

What about the modeler itself? If you decide to use this, remember that it is free, since there are some rough aspects to the user interface. It is very hard to tell which object is selected. The layout has an odd habit of resizing itself to be just a certain amount bigger than the browser window, so that you are forced to scroll it to reach the main commands at the bottom always positioned out of the window. Then after every operation, it unexpectedly re-scrolls back to the top of the page again. I felt that everything was always in an uncomfortable position and I was perpetually scrolling. An object created in one swim lane was not possible to move to another swim lane. Transition lines could be repositioned to route around things in most cases, but a few times it became impossible for mysterious reasons.

Here is a screen shot of the main toolbar:

Most of this is quite straightforward BPMN shapes. It took me a long long time to figure that the icon at the far right was the delete icon, and the big red icon is the close (exit) button. The symbols and the mechanisms seemed unfamiliar and did not follow (from my point of view) standard UI conventions.

The support fo XPDL seemed extensive. For example, here is a shot of the property panel for an activity:

This seems very complete. Notice expecially the “simulation” information which can be set up to include cost, waiting time and duration. Extended attributes can be added and edited. Deadline is supported, as well as icon position and size.

I did have trouble importing the standard process models from WfMC. There appeared to be a minor bug on every case that I tried which effectively prevented me from testing import. Given this hosted model, this may not be there the next time I visit.

Summary: A good initial offering. It seems to be competently implemented, but would benefit from a significant polishing of the user interface to make interactions match common norms and increase the comfort of casual users.