When in meshing mode, Fluent functions as a robust, unstructured mesh generation program that can handle meshes of virtually unlimited size and complexity. Meshes may consist of tetrahedral, hexahedral, polyhedral, prismatic, or pyramidal cells. Unstructured mesh generation techniques couple basic geometric building blocks with extensive geometric data to automate the mesh generation process.

A number of tools are available for checking and repairing the boundary mesh to ensure a good starting point for generating the volume mesh. The volume mesh can be generated from the boundary mesh using one of the approaches described.