I have an idea. Have 4 points. The 1 and 3 are the top left and top right corners of the net. The 2 and 4 are the bottom corners. Have 2 RigidBody2D polygons going from top left to bottom left and top right to bottom right. Then have a mesh texture that has its four corners attached to the corners. Make sure that the RigidBody2Ds are attached to the top left and right corners respectively with PinJoints and are allowed to freely rotate. Then have the two RigidBody2Ds be attached by their bottom corners to each other with a SpringJoint. Set the 2 and 4 (bottom) corners to be the position of the bottom end of the RigidBody2Ds. That might work.