  This paper aims to derive a definition of complexity for a dynamic spherical
system in the background of self-interacting Brans-Dicke gravity. We measure
complexity of the structure in terms of inhomogeneous energy density,
anisotropic pressure and massive scalar field. For this purpose, we formulate
structure scalars by orthogonally splitting the Riemann tensor. We show that
self-gravitating models collapsing homologously follow the simplest mode of
evolution. Furthermore, we demonstrate the effect of scalar field on the
complexity and evolution of non-dissipative as well as dissipative systems. The
criteria under which the system deviates from the initial state of zero
complexity is also discussed. It is concluded that complexity of the sphere
increases in self-interacting Brans-Dicke gravity because the homologous model
is not shear-free.
