The Prism Meshing Parameters includes a detailed description of the settings and functions that affect the prism meshing process.
You can use the ICEM CFD post inflation process to create prisms from existing volume or surface mesh, from any of the Tetra/Mixed volume mesh methods. Alternatively, using the Fluent Meshing method gives the option to create pre inflation prisms from an existing geometry, with or without surface mesh or volume mesh.
Note: To define a direction for pre-inflation prism growth into a volume containing more than one region of the same material due to an internal wall, an initial volume mesh (for example, tetrahedral by octree method) is needed.
See the Prism Mesh section in the User's Guide for more general information on prism meshing.