Okay, so 4.6 uses another raycasting system that essentially deals with click on stuff, IE raycast from screen to point. Using the old method of raycasting from camera is not recommended with the new GUI system since it will always cast through GUI element, which from a user perspective almost always undesirable. So first of all you need to add an Raycaster component to whichever camera you want to raycast. It's under Events. Second of all, any object that you want to be affected by this raycaster will need to implementing the IPointerClickHandler interface, which will allow you to have the OnPointerClick callback has PointerEventData as a parameter. The PointerEventData is the payload of the raycast hit and you can extrapolate whatever data is there to whatever it is you were doing previously. And obviously you still need to have a collider for the game object you want to click on.