Simple Portal is an asset which can help you achieve portal effect with just a drag and drop of a prefab into the scene.Simple portal handles smooth movements itlsef and the player will not notice any judder while moving from portal to portal. The portal works with any type of first person controller whether it is character controller or Rigidbody first person controller. Also, a simple first person controller is also provided with the asset. Rigidbody velocity is conserved across portals and you can smoothly throw a rigidbody (example a cube) without any inaccuracies or judder.