For an optimal FE mesh, it is sometimes necessary to refine certain objects or areas. A solid mesh refinement can affect the generation of an FE mesh on a solid.
In this way, you can define mesh refinements for solids with small dimensions in order to achieve an appropriate discretization. Conversely, for solids that play a subordinate role in the analysis, you can specify a "refinement" with a larger mesh size than the globally targeted FE mesh length. This has an advantageous effect on the calculation time.