Dear @Huajian.Xiao,
I’m glad you solved your issue.
Presumably you are referring to the IXY value of 9.9135213851E+006 kg-meter** 2 from the following forum topic: Inertial Moments of OC3-Hywind Components. I’m not sure I understand your question about it, but this represents the cross-inertia of the full OC3-Hywind system (platform + ballast + tower + nacelle + rotor) with respect to the (0,0,0) reference point.
Best regards,