Fading a object to hide it.

Hello,

     I am creating a pretty basic animation of the internals of a computer system.  I am wanting to gradually fade out a couple of parts in the animation to show a selected area.  Is there way a to do this gradually, Like some sort of fade control, rather than just turning it off right on a key frame?  Thanks for your help guys.

-C

SolidworksMotion Studies