I'm trying to perform an unilateral(one direction: Z) earthquake simulation with some lumps masses attach at each node. should I make them vibrate in all direction or only in the direction where the earthquake is assign?
and if i have to apply a multi-directional earthquake too, the lumps masses should be assign in all three directions(x,y,z)? kindly notice that for this type of structure the response in Z direction is mostly needed
