What is the difference between temporal and spatial interpolation

First Int. Google Scholar. Voting prediction using new spatiotemporal interpolation methods. Grumbach S. Manipulating interpolated data is easier than you thought. Moving Objects Databases. Hadjieleftheriou M. Efficient indexing of spatiotemporal objects. In Advances in Database Technology, Proc. Kanellakis P. Constraint query languages. MathSciNet Google Scholar. Springer, Kuijpers B. Trajectory databases: Data models, uncertainty and complete query languages.

Interpolation methods for spatiotemporal geographic data. Urban Syst. Indexing spatio-temporal trajectories with efficient polynomial approximations. IEEE Trans. Data Eng. Pfoser D. Capturing the uncertainty of moving-object representations. Revesz P. Spatiotemporal reasoning about epidemiological data. Shepard D. By default, a keyframe uses one interpolation method, but you can apply two methods: the incoming method applies to the property value as the current time approaches a keyframe, and the outgoing method applies to the property value as the current time leaves a keyframe.

When you set different incoming and outgoing interpolation methods, the keyframe icon in layer bar mode changes accordingly. It displays the left half of the incoming interpolation icon and the right half of the outgoing interpolation icon.

Linear in, Hold out C. Auto Bezier D. Continuous Bezier or Bezier E. Linear in, Bezier out. All interpolation methods used by After Effects are based on the Bezier interpolation method, which provides direction handles so that you can control the transitions between keyframes.

To learn more about how different interpolation methods affect temporal properties, experiment by setting up at least three keyframes with different values for a temporal layer property—such as Opacity—and change the interpolation methods as you view the value graph in Graph Editor mode in the Timeline panel.

To learn more about how different interpolation methods affect a motion path, experiment by setting up three keyframes for a spatial property—such as Position—with different values on a motion path, and change the interpolation methods as you preview the motion in the Composition panel. To change interpolation methods, right-click a keyframe, select Keyframe Interpolation from the menu that appears, and then select an option from the Temporal Interpolation menu.

To clarify the examples in the following descriptions of interpolation methods, the result of each method is described as if you had applied it to all of the keyframes for a layer property. In practice, you can apply any available interpolation method to any keyframe.

No interpolation is the state in which a layer property has no keyframes—when the stopwatch is turned off and the I-beam icon appears in the Timeline panel under the current-time indicator. In this state, when you set the value of a layer property, it maintains that value for the duration of the layer, unless overridden by an expression.

By default, no interpolation is applied to a layer property. If any keyframes are present for a layer property, some type of interpolation is in use. Linear interpolation creates a uniform rate of change between keyframes, which can add a mechanical look to animations.

After Effects interpolates the values between two adjacent keyframes as directly as possible without accounting for the values of other keyframes. If you apply Linear interpolation to all keyframes of a temporal layer property, change begins instantly at the first keyframe and continues to the next keyframe at a constant speed. At the second keyframe, the rate of change switches immediately to the rate between it and the third keyframe. When the layer reaches the final keyframe value, change stops instantly.

In the value graph, the segment connecting two keyframes with Linear interpolation appears as a straight line. Bezier interpolation provides the most precise control because you manually adjust the shape of the value graph or motion path segments on either side of the keyframe. Unlike Auto Bezier or Continuous Bezier, the two direction handles on a Bezier keyframe operate independently in both the value graph and motion path.

If you apply Bezier interpolation to all keyframes of a layer property, After Effects creates a smooth transition between keyframes. The initial position of the direction handles is calculated using the same method used in Auto Bezier interpolation. After Effects maintains existing direction handle positions as you change a Bezier keyframe value.

Unlike other interpolation methods, Bezier interpolation lets you create any combination of curves and straight lines along the motion path. Because the two Bezier direction handles operate independently, a curving motion path can suddenly turn into a sharp corner at a Bezier keyframe. Bezier spatial interpolation is ideal for drawing a motion path that follows a complex shape, such as a map route or the outline of a logo.

Existing direction handle positions persist as you move a motion-path keyframe. The temporal interpolation applied at each keyframe controls the speed of motion along the path. Auto Bezier interpolation creates a smooth rate of change through a keyframe. You may use Auto Bezier spatial interpolation to create the path of a car turning on a curving road.

As you change an Auto Bezier keyframe value, the positions of Auto Bezier direction handles change automatically to maintain a smooth transition between keyframes. The automatic adjustments change the shape of the value graph or motion path segments on either side of the keyframe. If the previous and next keyframes also use Auto Bezier interpolation, the shape of the segments on the far side of the previous or next keyframes also changes. If you adjust an Auto Bezier direction handle manually, you convert it to a Continuous Bezier keyframe.

Like Auto Bezier interpolation, Continuous Bezier interpolation creates a smooth rate of change through a keyframe. However, you set the positions of Continuous Bezier direction handles manually. Adjustments you make change the shape of the value graph or motion path segments on either side of the keyframe.

If you apply Continuous Bezier interpolation to all keyframes of a property, After Effects adjusts the values at each keyframe to create smooth transitions. After Effects maintains these smooth transitions as you move a Continuous Bezier keyframe on either the motion path or the value graph. Hold interpolation is available only as a temporal interpolation method.

Use it to change the value of a layer property over time, but without a gradual transition. This method is useful for strobe effects, or when you want layers to appear or disappear suddenly. If you apply Hold temporal interpolation to all keyframes of a layer property, the value of the first keyframe holds steady until the next keyframe, when the values change immediately. In the value graph, the graph segment following a Hold keyframe appears as a horizontal straight line.

Even though Hold interpolation is available only as a temporal interpolation method, the keyframes on the motion path are visible, but they are not connected by layer-position dots. For example, if you animate the Position property of a layer using Hold interpolation, the layer holds at the position value of the previous keyframe until the current-time indicator reaches the next keyframe, at which point the layer disappears from the old position and appears at the new position.

You can easily freeze the current frame for the duration of the layer using the Freeze Frame command. To freeze a frame, position the current time indicator at the frame you want to freeze. Time-remapping is enabled, and a Hold keyframe is placed at the position of the current time indicator to freeze the frame. If you previously enabled time-remapping on the layer, any keyframes you created are deleted when you apply the Freeze Frame command.

You can use Hold interpolation only for outgoing temporal interpolation for the frames following a keyframe. If you create a keyframe following a Hold keyframe, the new keyframe uses incoming Hold interpolation. You can apply and change the interpolation method for any keyframe. You can apply changes using the Keyframe Interpolation dialog box, or you can apply them directly to a keyframe in layer bar mode, in a motion path, or in the Graph Editor.

You can also change the default interpolation After Effects uses for spatial properties. For information on using Easy Ease controls to automatically ease speed between keyframes, see Controlling speed between keyframes. The Keyframe Interpolation dialog box provides options for setting temporal and spatial interpolation and—for spatial properties only—roving settings.

Current Settings. Preserves the interpolation values already applied to the selected keyframes. Choose this option when multiple or manually adjusted keyframes are selected and you do not want to change the existing settings. Rove Across Time. Smooths the rate of change through the selected keyframes by automatically varying their position in time, based on the positions of the keyframes immediately before and after the selection.

Lock To Time. They stay in place unless you move them manually. For more information on smoothing the rate of change through selected keyframes, see Smooth motion with roving keyframes. Convert selected keyframes to Hold B. Convert seleced keyframes to Linear C.