How to define damping ratio of vertical mode？

[honestliang]

Hello,I met a question about Rayleigh damping,I used following sentences to define the damping,but it seems like only define the horizontal damping ratio.
set xDamp 0.05;
set nEigenI 1;
set nEigenJ 2;
set lambdaN [eigen [expr $nEigenJ]];
set lambdaI [lindex $lambdaN [expr $nEigenI-1]];
set lambdaJ [lindex $lambdaN [expr $nEigenJ-1]];
set omegaI [expr pow($lambdaI,0.5)];
set omegaJ [expr pow($lambdaJ,0.5)];
set alphaM [expr $xDamp*(2*$omegaI*$omegaJ)/($omegaI+$omegaJ)];
set betaKcurr [expr 2.*$xDamp/($omegaI+$omegaJ)];
rayleigh $alphaM $betaKcurr 0 0
I want to define 5% damping ratio in vertical direction,how can I achieve it?Thanks a lot for your reply!

[mhscott]

The modes dictate which directions get the target damping ratios. All the other modes get whatever according to the damping spectrum.

[honestliang]

The modes dictate which directions get the target damping ratios. All the other modes get whatever according to the damping spectrum.

In fact,I'm not sure about it.If I define the stiffness and mass in both horizontal and vertical direction,then I use the sentences that what I have posted,I will get same damping ratio in both horizontal and vertical direction?