This is a paid asset, but now you can download PathMagic Free.
Detail this asset from Unity Store: Original Link
PathMagic is a UNITY editor extension that allows to create paths for smooth movement of game objects, such as cameras, players, scene objects, and so on.
You specify waypoints with 3D bezier control points, orientation, velocity, and PathMagic do the rest!
Take a look at the demo video
– Advanced in-scene and inspector editors
– Full integrated undo/redo and multiple objects edit support
– Full global position, rotation and scale of all waypoints for path adjusting
– Super fast path creation with best interpolation of orientation and velocity between waypoints
– Transform orientation specified manually or by a target Transform to follow
– Global follow target or follow path for orientation
– Symmetric / asymmetric tangents
– Constant velocity on path via path pre-sample
– Intelligent insert/Remove waypoint within the path
– Great simulation system: manage your path during the simulation in edit mode
– Path templates! Create linear and circular paths with ease
– Multiple objects on the same path
– In editor keyboard support
– Physics provided by specific joint
– Bake of path into standard legacy animations for performances
– Powerful and simple user interface
Create a path in less than 15 seconds!