  We develop a computational study of Casimir forces between three dimensional
(3D) finite objects with an internal granular structure. The objects in the
model consist of a finite arrangement of nanometer sized spherical particles
having a dipolar interaction. In this model system one can both study the basic
properties of the Casimir forces, and the effects from changing the parameters
of the nano-structured materials that constitute the particles; this last type
of study leads to a form of control of the Casimir force and an insight into
possible technological applications. We present examples of both kinds of
study.
