The next section of the prefix.grok file should consist of instructions for grid generation followed by an End instruction.
Currently, grok is capable of generating grids which are composed of either hexahedral blocks or triangular prisms. Figure 5.1 shows the local node numbering conventions for each of these elements and also the positive directions of the x, y, and z axes.
There is also an option for subdividing hexahedral block elements into 4-node tetrahedral elements (see Section 5.3.6). We will first discuss options for generating simple grids, followed by irregular grids.