Easing and Keyframe Interpolation

[Audio Starts at 00:00:00]

Kulshreshtha: So if you watch the animation carefully you may notice that some of the movement is choppy and not as smooth as it could be so we are going to add something called easing and this will make the movement a lot smoother. Let’s bring our attention to the word compass right here so you can see it simply moves onto the screen and it stops very suddenly and if you want to see this more visually you can actually go into the effect controls panel right next to the word position there’s a little triangle. If you click on the little triangle it will reveal something called a velocity graph. This basically shows the velocity or the speed over time and you can see that it changes very suddenly. It starts off at a certain velocity or speed and then it stops suddenly. That’s what’s represented by this sharp corner here. This is not natural movement.

Normally in the real world things will accelerate or decelerate so they’ll start smoothly and they’ll end smoothly and this is what easing allows us to do. It allows us to add acceleration and deceleration into the motion so here with the compass layer I’m going to go to the second key frame and you can right click and this will bring up some easing options which is also called interpolation. Sometimes it’s called key frame interpolation and there are two ways of doing it. There’s temporal interpolation that means over time, spatial interpolation is through space.

Now the one that we’re interested in here is temporal interpolation and there are several options in here but one of the easiest ways to apply easing is simply to go to these two the ease in and the ease out which are essentially presets and since this is the second key frame in the animation we want to use ease in. We want to ease into the key frame here so if I click on this one you’ll notice that now rather than being sharp and choppy the movement is very smooth and if you want to take this a step further you can even control this velocity graph by controlling these handles. Now it’s probably a good idea to zoom in at this point. I’m going to zoom in on the timeline. It’s also possible to increase the height of this velocity graph and then if I click on the key frame again now it’s going to be a lot easier for me to manipulate this handle here.

You can see that as I change the handle I’m actually modifying the velocity graph and then if I want to add easing to the first key frame I can do a similar thing. I can right click on the first key frame I’m going to go down to temporal interpolation and I’m going to ease out since I’m leaving the key frame I want to choose ease out and now you can see that the velocity starts off at zero, it accelerates up to peak value then it slowly decelerates and then I can also if I want this graph to be perfectly symmetrical I can manipulate the handles for each key frame here and now when I play this you may notice that the word compass slows down a little bit before it comes to a stop creating a smoother movement. Now when you ease in or ease out I’m going to right click and go back to these key frames.

Actually what it does it creates a bezzea key frame and the bezzea key frame has these little handles. Now if I ever wanted to remove easing from the key frame I would go back to temporal interpolation and I would make it a linear key frame and the linear key frame will take it back to its default. The default key frames are linear key frames. I’m going to undo that because actually I do like to have easing in this. I’m going to go down to the next word which is travels and I’m going to do a similar thing. I’m going to zoom in on the key frames so that I can see them a little bit better.

I’m going to reveal the velocity graph and on the first key frame I am going to choose ease out, on the second key frame I am going to choose ease in and now if I want I can manipulate these handles but often times the default value is pretty good and now if you look carefully you can see how the word travels slows down a little bit before it comes to a stop. That makes it a much smoother animation.

Now I’m going to go to the circle and on the second key frame I’m simply going to ease in to the second key frame that alone will make it smooth and then if I go to the star here I have a total of four key frames and I’m simply going to go to the second key frame like that and on the second key frames in this case you’ll notice that there is no temporal and spatial it just immediately takes you to temporal key frames and here I’m going to ease in to this key frame and then on this one on the second key frame for rotation I’m also going to ease in to that key frame and that should also allow it to become a little bit smoother.

When something moves quickly it’s a little bit hard to see and then if I reveal the velocity graphs I can also see how things are a little bit smoother over there and now what I’ve done is created a smoother animation by adding easing. There’s one other thing I want to cover here and you’ll notice that as we get to the end of the animation things start dropping out. This is actually very easy to fix. I’m just going to go to the very end of the animation and I’m going to extend all of the clips so that they end at the same time here like that. They’re all snapping to the play head and now we have the full animation with some gentle easing to make it smoother.