Missing nodes in action graph when i reopen the usd file which has been saved

As the title shows,i notice that,some nodes seem to be missing when i reopen the usd file which has been saved .However in the stage ,the nodes are still there.When i want to edit them again, i can not find them.Look at the pics below,where are the ros2_camera_helper,ros2_contex…
Does anybody knows why? THANK YOU!!!

Screenshot from 2023-07-26 18-14-39

Hi @gaozhao22 - This issue might be related to the way Omniverse Kit handles the saving of nodes in the USD file. When you save a USD file in Omniverse Kit, it saves the state of the stage, including all the prims, properties, and relationships that exist on the stage. However, certain nodes, especially those related to Omnigraph (the visual scripting system in Omniverse), might not be saved directly in the USD file. Instead, they are saved in a separate Omnigraph file (.omnigraph), which is then referenced in the USD file.

If you’re not seeing certain nodes when you reopen the USD file, it’s possible that these nodes are part of an Omnigraph and you need to open the corresponding Omnigraph file to see them. You can do this by going to Window > Visual Scripting > Action Graph in the Omniverse Kit interface.

If you’re still having trouble finding the nodes, it might be a good idea to check if there are any errors or warnings in the console when you open the USD file. These messages might give you a clue about what’s going wrong.