Untitled Document

Introduction

In this tutorial, we're going to animate the effect of frequency inversion. This is an optical illusion in which the eye perceives an object spinning in the opposite direction when at a certain speed - for example, the rim of a tire as a car accelerates.

Downloads

Tutorial Support Files

Spin Extra

Step 1: Open the File

Open the 'frequency_start' file. It is a simple model of a wheel-like object. Each part of the object is linked to an 'uberNull', and locked. This way, we'll only select the parent Null. to transform the set of objects.

Step 2: Add a Rate of Spin control to the Scene

Fron the Object Info Palette, select the uberNull.

From the Extras Menu, choose 'Spin'.

With the uberNull selected in the Popup Menu, leave the values at 0.00000, and click the 'Spin' button.

Step 5: Create the Keyframes

Open the Timeline, and expand the uberNull's hierarchy down to Spin:z

Option-Click the 'z' channel to add a keyframe.

Press the Return Key to open the Frame Dialog.

Enter 150, and click OK.

Enter 24 into the Spin:Z Field in the timeline.

Option-Click the 'z' channel to set the keyframe.

Step 4: Adjust the FCurve

Switch to FCurve Edit mode.

Select the keyframe at 150, and click the linearize button.

The curve now begins slowly, and rapidly increases speed.

Finished!

Choose Animate>Pencil Test, and set the range from 0 to 150. Notice how the wheel appears to slow & reverse & slow & reverse again? That's frequency inversion, and it can give an animation an extra bit of reality.

Now, wasn't that easy?