Dynamic Multi-directional Earthquake Ground Motion

[naba077]

Dear all,
Here, I've two questions;
1) Is there any command or method to apply multi-directional (3-D) earthquake ground motion to the 3-D structure? I found the method only applicable for two directional input.
2) I've a model of a building with foundation. Foundation is modeled with spring-mass-damper parameter. How can I run my model applying ground motion except for the foundation model (i.e. dynamic earthquake ground motion only for the superstructure)?
Thanks in advance.

[brag006]

Question not clear

[mhscott]

1) You can apply ground motion in three directions ... just use three patterns one each with direction 1, 2, and 3

2) Use a multi-support excitation