Using Field Expressions

You can use field expressions to create custom field data for visualization.

This task shows you how to:

Before you begin: You must display the results of a simulation to use field expression functionality.
See Also
Field Expression Syntax
About Field Expressions

Create Field Expressions

  1. From the Calculations section of the action bar, click Field Expressions .

    If no field expressions exist in the current simulation, a new empty expression is created automatically when you open the Field Expression Manager.

  2. Click to add a new field expression to the manager.
    A new field expression is created with a default name.
  3. Enter an expression in the Expression field.

    Press Tab to view a list of possible completions, including function names or field names. You can reference an existing field or another field expression by prepending the field name with any of the following:

    • $ for scalar fields.
    • $$ for vector fields.
    • $$$ for tensor fields.

    As you enter an expression, the dialog box periodically checks that the expression is valid. If it finds an error, it flags the error in the interface in the following ways:

    • The part of the expression that is in error is marked in bold red font.
    • The row of the invalid expression is colored red.
    • If the invalid field is selected, the reason for the error is shown in the Messages box at the bottom of the dialog box.

    Warnings are displayed in a similar manner, but marked in yellow.

  4. If desired, select an appropriate magnitude for this expression using the Magnitude menu.

    Results displayed using this expression will be shown in the units associated with selected magnitude. If no magnitude is selected (or you reset the selection using the default option), a commonly used magnitude matching the dimension of the expression is automatically selected. Preferred units for a given magnitude might be updating in user preferences.

  5. Click OK.

The simulation is updated to reflect changes made in the Field Expression Manager. Valid field expressions are available for visualization operations as a regular field.

Edit Field Expressions

  1. From the Visualization section of the action bar, click Field Expressions .

    All field expressions in the current simulation are shown in the table.

  2. Locate the field expression you want to edit, and click in its Expression input box.

    Tip: You can also display a list of field expressions in the Field Expressions page of the Feature Manager. Double-click on the field expression row to display the Field Expression Manager. The selected field expression is highlighted.

  3. Edit the selected field expression.
  4. Edit the selected field magnitude, if necessary.
  5. Click OK.

The simulation is updated to reflect changes made in the Field Expression Manager. Valid field expressions are available for visualization operations as a regular field.