The points used for symbol display on meshes coincide with the locations where the expression field is evaluated during the analysis. On geometry, when the symbols appear equally spaced along an edge or over the face of a model, Abaqus/CAE selects a random set of points to use for symbol display. The points selected for symbol display may or may not coincide with the locations where the expression field is evaluated.

In some cases the expression field cannot be evaluated at a given point due to an error; for example, division by zero. When this situation occurs, a message appears in the message area indicating that an error occurred while evaluating the expression field. As a visual cue to indicate that there is an error, the symbols displayed in the viewport are no longer scaled, even though the setting to scale symbols based on the expression field value is turned on. You can attempt to eliminate the evaluation error by changing the symbol density settings, which prompts Abaqus/CAE to select a different set of points to use for symbol display. For more information on changing the symbol density settings, see “Controlling the display of attributes,” Section 76.15.