Which one of these commands is the most efficient and preferable way to create stiffeners on molded parts?

The Rib command is specifically designed for creating stiffeners on molded parts due to its ability to generate features that are both structurally sound and optimized for manufacturing. When using the Rib function, you can easily define the rib's thickness, height, and profile, which is essential for ensuring that the stiffener serves its purpose effectively without adding unnecessary complexity to the model.

This command is particularly beneficial in injection molding and similar processes, where the shapes of parts are often dictated by the needs for rigidity and weight reduction. Ribs can be integrated into the part's design seamlessly, aligning with mold flow requirements while maintaining a strong structural integrity. Overall, employing the Rib feature streamlines the modeling process and adheres to best practices in design for manufacturability.