You can create JSON strings from objects and vice versa using the build-in Action Script statements:
Adding a JSON Adapter Operation to a Diagram
Expand the path to the JSON operations in the service panel. They reside below Base Types/Bridge Base/Base Types/Any:
You can drag out operations from the data model to any diagram:
The example shows how to add a JSON operation to a BPMN execution diagram:
Further configurations are not necessary, just add it to your diagram and draw the required connections to other elements.
JSONAdapter_Example
Click here to download a simple example model that shows the usage of the JSON adapter (classToJSON) in Scheer PAS Designer.