About Using an Exact Expression
You can use an exact expression, in the form of =(), to specify a value for a dimension. The expression enclosed within the parenthesis is evaluated and the exact value of the dimension is displayed. In an exact expression, the dimension value appears with the minimum number of decimal places required to display the exact value of the dimension. The maximum number of decimal places a dimension value can have depends on the number of significant digits in the dimension value, including those to the left and right of the decimal point. The maximum number of significant digits is 13.
You can use an exact expression to specify the dimension value field in the Dimension ribbon tab, in the embedded component in the graphics window, or on the dashboard.
Consider the following points when using an exact expression to specify the value of a dimension:
• You can use an exact expression to override the current global or local setting for the number of decimal places of the dimension value.
• If the number of decimal places required to display the exact value of a dimension is less than the default number of decimal places (as defined by the default_dec_places configuration option), the number of decimal places for the dimension will be set to the default value.
• Ensure that all the terms and numbers are enclosed within the parenthesis of the expression. For example, =(a/b – 12.543).
• You cannot specify a relation type expression of the form =(). For example, =(a/b) + 5, =(a/b) / (c+d), and so on.
• All parameter names and the dimension symbol appear only while you enter the dimension value in the form of an exact expression. After you finish specifying the dimension value, you will not see the exact expression, only the evaluated dimension value with the exact number of decimal places is displayed.
• When editing a dimension value specified using an exact expression, you will not see the original exact expression, but only the evaluated value of the dimension appears. If necessary, enter the required exact expression again to specify the value of the dimension.
• You can use an exact expression to specify the value of dimensions in a Family Table. You can use a combination of exact and non-exact expressions to specify the value of a dimension in a Family Table, but only for different dimensions representing different columns in a Family Table. You cannot use a combination of exact and non-exact expressions to specify the value within a single Family Table dimension (column). If you specify a non-exact expression for a dimension that used an exact expression earlier, all instance values are converted to the non-exact form of the dimension value.