Crack simulation in 3DEC 5.2

Hello, I would like to ask some questions related to crack simulation before a landslide.
I made a slope model, then I tried to cut the upper area into small blocks using DFN command. However, the blocks seem to slide “directional”. I found another solution of “Voronoi” command in 3DEC version 7.0 to generate the cracks, but I have no idea how to use it in 3DEC 5.2.
Please help me, or give some suggestions if you have any idea!

There is no voronoi in 5.2. You need to upgrade to 7, or you can import from another program (e.g. neper)