Template Details: Display Rules
Create Tempate - Display Rules
Display Rules:
Display Rules can compare the geometry of any points in a template. Because the geometry is evaluated at each template drop, the value of the Rule may change from station to station. Factors that may influence the results may include superelevation, independent controls, and/or which End Condition solves.
Display Rules can also evaluate whether a Component is Displayed at a template drop. Various conditions may cause a component to display at one template drop but not another. This is particularly true with End Condition components.
Display Rules are comparisons that evaluate as True or False. By themselves they change nothing. Every component can have a single Conditional Expression that references the Display Rules and that evaluates as True or False. When False the Component will not display. When True the Component is not forced to display, it is allowed to display. Reasons a component with a True Conditional Expression may not display include:
- It being part of an End Condition that was not used
- It being a Child of a Component that is not Displayed
The Conditional Expression can be as complex as the engineering requires; any number of Display Rules can be joined with the AND, OR, and NOT operators and sequenced (grouped) with parentheses. Regardless of the complexity, the expression evaluates as a simple True or False. Operators are evaluated from left to right. An Expression within parentheses is evaluated as true or false value before further comparisons are applied. The precedence is as follows:
- Parenthesis
- NOT
- AND and OR
While sometimes including parentheses does not change the value of a Conditional Expression, consider including them to improve the readability of the expression.
Components in the dialog display in accordance with their active Conditional Expression value, if defined. The Create Template dialog has a Display All Components check box. If their Conditional Expression is True, they Display. If False they do not display when the Display All Components check box is clear. When the Display All Components check box is set, they Display as dotted lines.