General Engine Configuration has three sections, Engine Ping, RGraph, and Shared DDC, as shown above:
Engine Timeout (seconds): It is the place where you define the period of Engine timeout; in other words, it refers to the duration that RealityHub waits for a response from the Engine before identifying changes in its state.
Engine Ping Interval (seconds): Defines the length of time the RealityHub waits between ping packets.
This setting allows you to define the minimum time between history saves.
Shared DDC (Derived Data Cache) is a network drive that all Engines can read/write derived data. RealityHub allows you to define which storage your Engines will use for the derived data cache by defining a UNC Path. It can log in to the Shared DDC network through your Username and Password.
Enabled: When you activate the Enabled checkbox, your Engines reach your Shared DDC and can read/write.
Path: Area for defining the UNC Path for Shared DDC.
Username and Password: Administrative credentials of the computer your Derived Data Cache is located
Please remember that the Path you define must be a UNC Path.
Your Engines must have administrative rights to reach the Shared DDC.
For more details about Shared DDC, please visit: https://docs.unrealengine.com/5.0/en-US/derived-data-cache/