In 3d Studio Max, there is more than one way to skin a cat. I've seen in many forums out there several methods for animating the rotation of wheels, balls, helicopter blades, etc. There is no single correct way to achieve this since it will depend on your needs. This tutorial assumes you have at least some background using 3d Studio Max, so lets jump right in.

1. Of course, you're going to need a model of some sort. For the purposes of this tutorial, you may want to simply have a long box that represents the blade of a helicopter. Draw it in the top view and make it a long

rectangle. Once you have the box completed, make sure the pivot point is set to the absolute center of the box. Make sure the box is selected, then click on the Heirarchy tab. Next, click on Affect Pivot Only, then Center to Object. This centers the pivot point on the box object.

Position the time slider at the last frame, make sure the box is selected and the animate button is still clicked red. Click on the Motion icon (the rolling wheel in this version). Under PRS Parameters, click the Rotation button and type in the Angle window. Select a positive number that's really high. Depending on the length of the animation, this number should be set higher and higher. I'll tell you why in a moment. Type 1200 in the Angle area and hit enter. Watch the animation. Now enter 12000 and watch the animation. Now the rotation is MUCH faster. But, there's a good reason to set the rotation this "fast". Undoubtedly, you're going to want motion blur. Use object motion blur with Duration (frames) set to 1 and Samples/Subdivisions set to 16. This gives flawless blur effects and doesn't take nearly as long to render as a slower rotation with higher Duration (frames) settings.

3. Now here's the good part. We want our blades to start from dead still and gradually increast speed, ie. like a real helicopter would. This is easier than you might think: Go to the FIRST key for the box (underneath the time slider) and right click on the key. Select the rotation parameter and the above dialogue will open. Change "Ease From" to 50 and exit the dialogue. Watch the animation. The box starts slowly and builds up speed. Assuming you started working with 101 frames (0-100), the box will start slowly and jump to fast pretty quickly. You will have to lengthen the overall animation and tweak the Angle (speed) to get exactly what you want. Download the sample avi above to see what I came up with. As always, experiment to see what else you can do. Please send you comments on this tutorial and requests/suggestions for more! Thanks!