Rules

Define validation formulas that restrict invalid parameter combinations with user-facing messages on Print CAD standards.

The Rules tab defines validation logic that prevents customers from ordering parameter combinations that cannot be produced. Each rule consists of a formula and a message — when the formula evaluates to true, the message is displayed to the customer and the order is blocked until they adjust their dimensions.

Rules run on the storefront in real time as customers modify parameters. They act as a safety net between the min/max limits on individual parameters and the complex geometric or production constraints that govern whether a specific combination of dimensions is actually manufacturable.

Access Rules

Open any standard from the Custom Libraries list.
Select the Rules tab in the edit form.

Rules Grid

Column	Description
Restriction	The formula expression that triggers the rule. When this formula evaluates to true, the associated message is shown and the configuration is considered invalid. Formulas use the same variable names defined in the Parameters tab.
Message	User-facing text displayed when the restriction formula is triggered. Should explain what is wrong and how to fix it (e.g., "Width must be at least twice the depth for this standard").
Action	Edit and Delete buttons.

Add or Edit a Rule

Click Add Rule in the toolbar or Edit on an existing row to open the rule dialog.

Field	Description
Formula	The restriction expression. Required. Uses parameter variable names (e.g., `W`, `L`, `D`) with comparison and arithmetic operators. The rule fires when this expression evaluates to true.
Message	Text shown to the customer when the formula triggers. Write clear, actionable guidance so customers understand how to correct their input.

Formula Examples

Formula	Meaning
`W < D * 2`	Width must be at least twice the depth
`L + W > 48`	Combined length and width cannot exceed 48 inches
`D > L`	Depth cannot exceed the length

Associations

Print Store

Area	Effect
Parameter validation	The storefront's `ParametricHelper` evaluates all restriction formulas against the current parameter values. When any formula evaluates to true, the associated message is displayed and the Add to Cart action is blocked until the customer adjusts their dimensions.
Real-time feedback	Rules are evaluated as parameters change, providing immediate feedback. This prevents customers from reaching checkout with invalid configurations.

Parameters — Define the variables that rule formulas reference
Expression System — Arithmetic operators and functions available in rule formulas
Sandbox — Trigger and verify rule messages by testing different parameter values