Sets the COG location of piping, pipe supports, equipment, or structure.
You can also modify the COG location in the properties palette and data manager.
Access Methods
Ribbon: 
Analysis tab 
Edit COG
Command entry:
planteditcog
List of Prompts
The following prompts are displayed.
Edit
Reset COG
Restores the default COG location for the plant object.
Select another object
Saves COG changes and selects a different plant object.
End Command
Saves changes and ends the command.