Utility plug-ins derive from the class UtilityObj. A utility plug-in differs from a global-utility plug-in (GUP) in that it has an associated roll-out panel and appears in the utilities section of the command panel.
UtilityObj::BeginEditParams()- Called when the utility is selected from the command panel.UtilityObj::EndEditParams()- Called when the utility is no longer being used from the utility branch of the command panel.UtilityObj::SelectionSetChanged() - Called by 3ds Max when the selection set changes.UtilityObj::DeleteThis() - Called when 3ds Max requests the plug-in to be deleted. A typical implementation would be { delete this; }.UtilityObj::SetStartupParam() - Called by 3ds Max after UtilityObj::BeginEditParams() when the user starts the utility from the command line with the -U option and passes an argument to the utility.