Within the context of a'.sim' file, when either performing a 'model setup check' or trying to solve a 'solution', an error/action message similar to that shown below is reported in the 'information' window:
Some elements in mesh "ThinShell(1):2d_mapped_mesh(1)" have missing nodal thicknesses in their element associated data.
ACTION: Ensure that all elements in mesh have at least one non-zero nodal thickness value defined or define a thickness value in the physical property of the mesh collector.
For the 2D element mesh(es) identified by the error, check that a value for the shell element thickness has been defined.
Note that the shell element thickness may have been defined by way of a physical property table, element associated data, a field or derived from a mid-surface.