With the option tipa dirdiff, the tilted independent pixel (column) approximation (TIPA, the same as TICA) is carried out, where a 3D-cloud file serves as input and the columns are tilted towards the sun (see, e.g., Wapler and Mayer, 2008). tipa dirdiff works with all 1D-rte-solvers. When choosing tipa (tipa dir), from the ”tilted clouds” only the optical depth for the calculation of the direct radiation is derived and used later to calculate the diffuse radiation. To calculate the diffuse radiation, the original cloud-matrix is still necessary / maintained. tipa dir works only with Roberts (Buras) delta–Eddington two–stream model rodents. For both tipa options, a mc_sample_grid has to be specified as Nx Ny dx dy. A 3d-cloud-file (with flag 3) serves as input (see wc_file 3D). The output is written into mc.flx(.spc), however, a basename via mc_basename can be given.