Hi Clemens,

I have the following 3d model and was looking to find the frequency in the xz and yz plane of the model.

All my results however seem to be in the xy plane:

Hence my question on would it only be possible to split each frame out and find the natural frequency of each frame?

As an alternative for seismic design. The frequency of a structure is 1/18/sqrt(deflection) when the structure is loaded with it’s self weight in the direction of deflection.

I was wondering if there is an easier way of finding the displaced centre of gravity of the structure for the purpose of this maths rather than inserting a new node connected to the structure with an element of zero mass and restrained vertically?