  We present a general method to solve radiative transfer problems including
scattering in the continuum as well as in lines in 3D configurations with
periodic boundary conditions. he scattering problem for line transfer is solved
via means of an operator splitting (OS) technique. The formal solution is based
on a full characteristics method. The approximate $\Lambda$ operator is
constructed considering nearest neighbors exactly. The code is parallelized
over both wavelength and solid angle using the MPI library. We present the
results of several test cases with different values of the thermalization
parameter and two choices for the temperature structure. The results are
directly compared to 1D plane parallel tests. The 3D results agree very well
with the well-tested 1D calculations.
