Seismosoft | Earthquake Engineering Solutions

I am interested in studying the behavior of 3-D frames, in near-field earthquake. While doing some tests, I noticed that, however, by applying a time history load vertically, the effects on the structure are minimal, or zero. I tried to modify the loading of the masses, but the result has not changed. It is as if the mass along z were not detected

Can it be that you have deactivated the masses in the Z-direction (Project settings>Gravity in Mass)?
Seismosoft Support

I have considered only the mass along z, setting as multiplier -9,81, and as definizina of the loads, deriving from the masses they define coefficients defined by the user

the derivative that I observe is only related to permanent loads, with a small rate relative to the seismic action, amplified by 3 times compared to the real

Not sure we can follow what you did. If you restore the default settings (click on the Program Defaults button) you will get probably a normal program behaviour.
Seismosoft Support