If you're a motion graphics designer working in After Effects and you lust after those buttery smooth pieces that you see the professionals making, look no further. Finally unlock the secret weapon to your own jealousy inducing, smoother than smooth animations. Ever wonder how to get those really fluid animations that you see in commercials on TV? You know the ones; the slick looking vector images with swift moves that seamlessly melt into slow stops. All the animators creating those have a secret. It's a secret that might seem scary when you call it by name but when you learn how to control it and master its power, it will be your new best friend. Keyframe interpolation. Now if you even know a little bit about this subject, you'll know that in name it is rather broad. Keyframe interpolation simply means that there is a certain amount of time between two keyframes and that time can be interpolated to make the animation look completely different based on how the motion or distance is distributed over time. If you are used to just setting your keyframes and letting them default to linear interpolation then you are creating an animation with no contrast. This is not good. When talking about animating something even as modest as a line of text, it can have life and directly illustrate what that word says with well placed keyframes that have been correctly interpolated. Linear keyframes will rarely get you to this level of communication. Sure they have their place but the contrast in the speed and motion is what separates the amateurs from the professionals. So let's say that maybe you've discovered the easy-ease keyframe type. It is possible that without even knowing it you have begun to delve into a little more contrast in your animations. However, do you really understand why you are adding easy-ease? It does makes things look smoother but what if you're animating an apple falling from a tree? In that case easy-ease would make it look like the apple knew where the ground was. So unless you're animating an anthropomorphic apple stay away from dropping easy-ease on everything.   The key is in the Graph Editor. That is where the magic happens. The graph editor is just like editing a Bezier shape with handles. There you can control the curve of your animation and with it the speed and how the speed is distributed over time. There are also a few other tricks as well. You can use Auto Bezier style keyframes to cause an animation to hit a specific point without changing the overall interpolation of your move.   You can also try using hold keyframes for fixing overshoot or creating a stepped animation. You can try roving your keyframes across time, if you want to see how After Effects will distribute the positions to equalize the distance with the time allotted, for the whole move. There is also another interpolation distinction that is lost on many After Effects users. Temporal Interpolation versus Spatial Interpolation. Temporal Interpolation affects how a property changes over time in the timeline. Spatial Interpolation affects the shape of the path that the object is physically taking. So when you're thinking of smooth animations you're probably noticing the contrast of the Temporal Interpolation. When you see something moving around in a smooth (not robotic) path you're noticing the Spatial Interpolation. Knowing the difference between these two types will be the key to knowing what to change when your animation just doesn't look right.   There is so much to learn about keyframe interpolation and there are literally thousands of scenarios that require a different interpolation to look just right, but if you have a foundational understanding of what the different types mean and how you can change them to work for you, then you are on your way. If you want to learn more about how to master keyframe interpolation check out Demystifying Keyframe Interpolation in After Effects.