Generate and plot 3D solution, given 2D solution

Hi all,

I'm using weak-form modeling to solve for a vector field u(x,y,z). The vector field has 3 scalar components u1, u2 and u3.

I know the functional form of the solution in the z-direction; it is given by

u(x,y,z) = u(x,y)*cos(Kz)

So I only solve for u(x,y) in a 2D-model. All I want to do now is take this solution u(x,y) and use it to plot u(x,y,z) in 3D displacement plot. However, I have been unable to do so. I can't find any buit-in way to do this.

Does anyone have an idea of how to do this?

Thanks!