  We develop a numerical method to simulate mechanical objects in a viscous
medium at a scale where inertia is negligible. Fibers, spheres and other
voluminous objects are represented with points. Different types of connections
are used to link the points together and in this way create composite
mechanical structures. The motion of such structures in a Brownian environment
is described by a first-order multivariate Langevin equation. We propose a
computationally efficient method to integrate the equation, and illustrate the
applicability of the method to cytoskeletal modeling with several examples.
