Question about mass and load

[Aslinn]

Hi,
I am a bit confused about the mass and load concepts in Seismosoft. Specifically, when should I use the lumped mass and when should I use the permanent loads? I noticed that the lumped mass would affect the frequency of the structure, while the permanent loads would not. Therefore, my understanding is that the mass contributing to the damping should be assigned as lumped mass. For example, the self-weight of the slab is lumped mass, self-weight of non-structural members such as finishes and imposed loads due to occupancy are assigned as permanent loads. Is my understanding correct?
Furthermore, under Project Setting, Gravity and Mass, for the options 'Define mass from' and 'Define loads from', under what circumstances do I need to change the default?
Best Regards,
Aslinn

[z.gronti]

Dear Aslinn,

If you want to assign the permanent loads as mass, you may just select the proper option in the Gravity & Mass tab of the project settings. I do not think that there is any rule for whether you should assign mass elements or element loads. It depends on your modelling assumptions in combination with the proper selection in the Gravity & Mass tab.

[roshen.rj]

In seismostruct, what does the term 'W' mean in the 'Gravity and Mass' section under 'Project Settings'

[z.gronti]

Dear roshen.rj,

The W is for warping and refers to the 7th degree of freedom applicable only for Rack elements.