coupling effect of ground motion in horizontal,vertical

[drowning6]

Dear everyone,

Do we need specific setting to get the coupling effect of structure response with horizontal and vertical ground motion at the same time?
I just can not find the coupling effect in my model...

Sorry to bother everyone.

[mhscott]

No, nothing special is required. Check your model (mass, elements, etc.) to make sure it can capture coupling effects.

[drowning6]

thx, Dr. Scott.

And I found it 's because I set three zerolength elements in orthogonal directions.
But they do not work toghether. I mean it seams the zerolength element only work assuming the other two direction is fixed.
Is this the setting of the zerolength element?

And I will open a new topic to ask this quesion.