Reality 4.27

OnChanged_Event Callback

OnChanged_Event Callback feature allows you to manipulate your code with “CustomEvent” when your variable is changed.


  • Events name must start with “OnChanged_.
  • The variable you assigned must be Public
  • Event name and variable after the underscore symbol (_) must be the same
  • Events names are case-sensitive


  • Create a Blueprint Class and double-click on it. This action leads you to the Event Graph.
  • In the Event Graph, click on ADD COMPONENT button, and type ZD. This actin lists all ZD components. Select the ZD ACTOR component.
  • Select the ZD ACTOR from the Components tab
  • Go to the Variables section, and click + VARIABLE button
  • Add a BOOLEAN parameter, click on the 👁 to make it Public so it can be exposed to the RealityHub Nodegraph
  • Go to the Event Graph canvas, right-click and type Add Custom Event
  • Your variable name must be the same name after “OnChanged_.” In this example, Custom Event’s name is “OnChanged_MyBoolean”
  • Drag and drop the variable into the Event Graph canvas, select the GET MYBOOLEAN
  • Right-click on the Event Graph canvas, type print screen, and select the Print Screen node under the Utilities > String.
  • Connect the OnChanged_MyBoolean node’s exec output pin to the Print String node’s exec input pin
  • Connect MyBoolean’s output pin to Print String’s In String input pin and click on the PLAY button
  • Switch to the RealityHub user interface
  • Activate the Nodegrap/Actions module
  • Find and select the ZD ACTOR node