- [Instructor] For total control of animation data
use the Curve Editor to adjust the interpolation
between key frames.
That's the filling in of unknown data.
In computer animation, we set values
at particular points in time.
And the computer fills in all the in between data.
We control the in between or in interpolation
in the Curve Editor.
I'll select the animated object, the camera
and launch the Curve Editor
from its button on the main toolbar.
In the previous movie, we deleted the static tracks.
The only animated tracks are X position, Y position
and the blue Z rotation.
We just need to display those curves in the graph.
We can click the button frame horizontal
and value extends,
or even better we can use the keyboard shortcut, which is Z.
We see a classic S curve shape
and that results from the default interpolation type
which is auto tangents or auto Bezier.
The rate of change in any track value is indicated
by the slope of the function curve.
A steep slope indicates a fast change.
A shallow slope indicates a slower change
and a flat area or a plateau means no change over time.
To use a different interpolation type select one
or more key frames in the graph.
I can select all of these keys
by drag a big selection rectangle around all of them.
And once those are selected,
we can change their inter interpolation type.
The Curve Editor toolbar area up here is a bit cluttered
but over on the right side is the key tangents toolbar.
And there we can choose different interpolation types.
Let's try a linear transition.
One of the buttons up here is set tangents to linear.
And now we get straight lines
in between each of those key frames.
And we don't see those blue tangent handle lines
that we saw a moment ago.
Let's see what this looks like.
We'll go into our playback controls and play the animation.
And we see that there's kind of an abrupt transition there
at frame 70.
And again, that's happening
because we've changed our interpolation type to linear.
Okay, I'll stop that.
And those key frames are still selected.
I'll set them back
to their default inter interpolation type
which is auto tangents.
Click the button set tangents to auto.
Now we're back where we were.
Play that animation again
for comparison's sake, and it is better.
The default auto Bezier tangent interpolation is better
than linear in this case
but we can still do better.
To create a smooth animation,
we need smooth flowing curves
and I can start by deleting the key frame
on the X position curve here at frame 70.
It'll be easier to see that that's an issue
if we zoom in a little bit.
I'll click to deselect all those curves
and zoom in with Control + Alt and middle mouse.
If I drag upward,
I'll be only zooming in the value dimension.
So we've got a little bit of an S curve here.
There's a bit of a bump there that we don't actually want.
We can actually make this better by just deleting that.
Now this is subtle in the graph
but camera animation is very sensitive.
Any tiny change in the keyframe value
will have a noticeable effect to the camera framing.
So just deleting that keyframe is going to even it out.
I'll select it and press delete on the keyboard.
And now we see the change in that curve.
We can reframe those curves once again with the Z key
and rewind and play back our animation and see that change.
And it is smoother having just removed that little bump,
we've actually made this quite a bit better.
Okay, now let's look at moving key frames around.
Let's select that Z rotation track
and frame that it with the Z key.
We can edit key frames in a couple of different ways.
For example, we can use key statistics.
If we select any key frame
then down here at the bottom toolbar, we have statistics.
We'll see the frame number
and the key frame parameter value displayed.
And I can edit either one of those.
So for example, I can send this key frame later in time.
I can set it to a time of frame 30
and now the rotation's going to start later.
We can rewind and play that back
and see what that looks like.
Not really what I wanted
but it's a good demonstration of how I can use statistics.
And of course we can click
and drag to move key frames around too
because the default tool is move keys.
So if I click on a key frame or a selection of keys
I can move it either in time or in value at the same time.
Okay, I'll undo that with Control + Z.
If I want to constrain that movement
I can use the control key.
Pull down control
and drag left to right to change only the time
and not the value.
I can send that back to frame zero.
Hold down Control
and drag up and down to change the value, but not the time.
And when I release the mouse
we'll see the change in the view port.
And actually, if we're parked on that current key frame
it'll make it even more obvious what we're doing.
So in this case
I can just rewind, go to start, go to frame zero.
And again, I can hold down Control and drag.
And when I release the mouse, the view port's update
I can see the composition I'm going to get
by setting that key frame to that particular value
on frame zero.
We can make this even better
by enabling a feature called interactive update.
And that'll give us really immediate feedback
while we're dragging the mouse.
And that's found
in the Curve Editor menus view, interactive update.
And now when I hold down Control and drag on that key frame
at the current time, I'm getting a real time preview
of exactly the result I'm going to get.
So I can bring this down and release the mouse.
And now I know for certain
that this is the frame I'll see on frame zero.
All right, that's a little bit
about editing key frames and changing interpolation types.
In the following movie, we'll edit the interpolation
by adjusting the position of tangent handles.