We propose an automated method for computing inductive invariants used to proving deadlock freedom of parametric component-based systems. The method generalizes the approach for computing structural trap invariants from bounded to parametric systems with general architectures. It symbolically extracts trap invariants from interaction formulae defining the system architecture. The paper presents the theoretical foundations of the method, including new results for the first order monadic logic and proves its soundness. It also reports on a preliminary experimental evaluation on several textbook examples.