Gravity: Smooth Landing

In Pixar's Toy Story, after Buzz Lightyear soars around the bedroom, Sheriff Woody says, "That's not flying—it's falling with style!" We can tell the difference, visually, between something that's flying under power and something that's falling or gliding. Using a paper airplane for this project helps us to visualize a different effect of gravity. The factors of wind resistance and loft keep the airplane from making a dramatic freefall as the orange does. (However, I have seen some horribly designed paper airplanes that defy all principles of flight and behave more like a brick than an airplane!)

The image I chose for this project was originally a flattened TIFF file with an alpha channel, which I used to extract the plane for the background. I added a feathered selection for creating a slightly blurred shadow layer in Photoshop. The finished two-layered file, PaperAirplane.psd, can be found on the DVD.

Create a new project in After Effects and import the airplane file as a composition. Change the composition dimensions to 640 x 480 NTSC, and then change the Background Color to white. Move the airplane in the Comp window to the upper-left corner along the top, just outside the window's boundaries. Move the shadow to the left side, just outside the window and down about 150 pixels from the airplane (Figure 4.6).

Figure 4.6

Position the two layers outside the Comp window for their final approach.

Figure 4.6

Position the two layers outside the Comp window for their final approach.

Select both layers on the Timeline window and hit the P key to get the position settings; click the Stopwatch for both layers and move the Indicator to around the 1-second mark. Move the airplane in the Comp window down past the center of the window, and drag the shadow a little bit under it. Move the Indicator down about 10 frames, and continue to drag the airplane and shadow together along the same direction as the combined landing angle about 50 pixels (Figure 4.7). The shadow will need to enter the window before the plane in order to create the illusion of a top light source; nudge the position marker for the airplane layer down a few frames so its movement starts later. To give the shadow a better sense of depth, set the beginning opacity to 0% (press the T key and set the Stopwatch) and set the landing opacity to 65% on out to the end.

Because this animation is of a fairly slow descent, we want the airplane to experience a little lift upon landing. This is where the motion and mass of the airplane cause a slight bit of air compression against the floor surface, which causes it to nose up very slightly and scoot across the floor before the drag on the floor surface makes it come to a complete stop. A simple, slight upward rotation at the end of the flight path provides this effect.

| gj | Composition PapefAifplane Comp l"| t | k ~ —^

| gj | Composition PapefAifplane Comp l"| t | k ~ —^

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Figure 4.7

Creating a believable flight/landing path requires an eye for perspective and attention to timing.

Figure 4.8

A slight rotation at the end of the flight path establishes the perspective of the floor surface to the plane.

Figure 4.8

A slight rotation at the end of the flight path establishes the perspective of the floor surface to the plane.

Figure 4.7

Creating a believable flight/landing path requires an eye for perspective and attention to timing.

Select both layers in the Timeline window. Starting just before the 1-second mark and the actual landing of the plane, create a Rotation marker set to 0°. Halfway between the landing point and the end of the skid, set a Rotation marker for both layers to -10° (Figure 4.8). The effect is very subtle, but it reinforces the illusion of the plane actually landing on a hard, smooth surface.

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