The Expression Operator () defines an operator that evaluates parameterized expressions on specified selections.

For information about the settings in the Operator Name and Selection sections, see the Operators section.

In the Expression field, enter the expression for the operator. The expression can contain both the specified formal argument names and other variables, which are assumed to exist on the selection. Press Ctrl+Space to choose from previously defined parameters, mathematical constants and functions, operators, and physical constants that you can insert into the expression at the position of the cursor.

In the table of arguments, enter the name of each formal argument in the Argument column and its expected dimensions, in the form of a unit expression, in the Dimensions column. The dimensions are used when deriving the operator’s dimensions and for checking unit consistency when the operator is used in expressions. In the Argument type column, choose Expression to pass the input argument as an expression, or choose Value to pass it by its value. Passing an input argument by value can be useful if it is a spatial coordinate in a component geometry that is then evaluated in another geometry, for example. Use the Delete button () underneath the table to delete the selected argument, if needed.