Petri Net Visualizer : Cannot invoke "org.processmining.plugins.graphviz.visualisation.DotPanel.getDot()" because the return value of "org.pm4knime.portobject.AbstractDotPanelPortObject.getDotPanel()" is null

I tried to evaluate my process model for two use cases built by dfg miner as given in the Ticketing Management workflow.
for one use case im able to run petrinet visualizer whereas for the othe rone im getting the below error
Cannot invoke “org.processmining.plugins.graphviz.visualisation.DotPanel.getDot()” because the return value of “org.pm4knime.portobject.AbstractDotPanelPortObject.getDotPanel()” is null.

Could you please guide me to fix this error

Hi @rajab ,
thanks for posting.
Could you please provide us with links to the workflow you mention and your workflow if possible, such that we could reproduce the error and check what is happening under the hood?

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Hi Daria,

One of the activity name in the second use case data has the symbol ‘&’, after replacing it as ‘and’, i’m getting the expected result. Petrinet visualizer is working fine after this change in data.


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