Trioptimal layout is also referred to as radial, since the panels are radial typically oriented towards the corners of the sail resulting in a triangular shape. This layout distributes the forces the sail is exposed to optimally and helps maintain the shape of the sail. The panels that make up the radial layout are carefully arranged to follow the load pattern, ensuring a strong and stable sail.
Upwind sails in a trioptimal layout are typically made from a laminate cloth, that is a sandwich cloth constructed of more layers. However, you will find a few trioptimal designs in a woven polyester cloth, and most nylon downwind sails are designed in a trioptimal cut.