A catalogue lists what exists. A rules engine determines which combination of those products, dimensions, components and options can exist together for a specific market, role or project. It evaluates the current configuration whenever a relevant input changes and returns a controlled result.
That result may allow the choice, require another component, calculate a derived value, replace an option, display a warning, request specialist review or stop an invalid state. The important part is consistency: the saved configuration must mean the same thing to the 3D scene, live-price calculation, quote, order and optional bill of materials.
Rules are not the interface. A disabled control, filter or wizard step is only the visible effect. The real product logic needs stable identifiers, ownership, messages, versioning and tests behind it.