this depends if you want the rope to be rigid or flexible. If rigid, please use a Cylinder node (a very tall one so it looks like a rope) and move/resize/rotate it using a Transform node. Please note that you cannot specify kinematic joints in Simulink 3D Animation, so you must compute the rotation of the rope and feed it into the Transform node yourself.
Showing a flexible rope is also possible, but it would be quite complex to compute the coordinates so that the rope realistically models the behavior of a flexible rope.
Please take a look at the "vrcrane" family of examples (vrcrane_traj, vrcrane_panel, vrcrane_joystick) to see an example how a rope connecting a crane with a load can be modeled.
Good Luck, Jan