Using Weighted List Controllers

Autodesk 3ds Max Tutorials > Animation Tutorials > Animating with Auto Key: Bouncing a Ball >

There are many different animation controllers in 3ds Max. Each has its own attributes, strengths, and uses, and each has associated techniques. You can combine different controllers for unique animation effects using weighted list controllers. By changing or animating the weights of controllers in the list, you can adjust each controller’s effect, and animate in a nonlinear way. Here, you’ll learn to animate the weights and to see what they can do.

Use the Weighted List controller:

With the Position List controller, you can add other controllers on top of the Bezier Position controller you already have. Here you will add a Noise controller to layer the animation of a Ping-Pong ball.

Choose File > Open to load pingpong_volley.max.
A Ping-Pong ball and table are visible.

TipIf the texture on the table looks wrong, right-click the Perspective viewport label and choose Texture Correction.

Ping-Pong volley
Play the animation.
The Ping-Pong ball bounces over the net in a simulated volley. The last four bounces happen in place. You can use weighted list controllers to remove those last four bounces, and replace them with a rolling motion. A Noise controller can be added to get rid of the bouncing, and instead you will have the ball wobble around on the table, then stop.
Select the Ping-Pong ball.
Open the Motion panel and expand the Assign Controller rollout.
Notice that the Assign Controller rollout displays the Position controller as a Bezier Position for the Ping-Pong ball. Use the pan hand in the window to read the label.

There are at least three different places where you can assign a controller to an object: in Track View windows, on the Motion panel, or from the Animation menu. You'll use the Animation menu to assign the controller, and the Motion panel to edit the weights.
On the Animation menu (not on the Motion panel), choose Position Controllers > Noise.
The viewport trajectory changes into a frenzied red spline. Don't worry, this is correct.

Noise controller: A frantic trajectory

NoteWhen you assign a controller from the Animation menu, the software automatically adds a weighted list controller to the object.
On the Motion panel, in the Assign Controllers rollout, expand the position list, and then the Noise Controller.
You can see that Noise Strength is indented beneath the Noise Position. If you scroll down a little, you can see that the Weight is listed as well.

The new Noise Position track appears below the Bezier Position track. The old animation has not been replaced; instead, the new Noise controller has been added to it.

If you play the animation, the ball flies all over the place. It is following the position controller tracks and the noise controller tracks. This probably isn’t what you want here. You will need to adjust the noise parameters and the weighting of the controllers.

Adjust the Noise Frequency and Strength:

In the Assign Controller list window, highlight and then right-click the Noise Position entry and choose Properties.
The Noise Controller properties dialog is displayed
Change the Frequency to something very small, like 0.009.
Change the Z Strength to 0.0.
ImportantIf you miss this step, the tutorial won't work. The Z strength counteracts the up-and-down bouncing movement.
Change the X Strength and Y Strength to 1.0.
This creates the motion of the ball wobbling around on the table surface.

Noise Controller Properties dialog
Play the animation
The Noise is now less jittery, in fact barely visible. You need to weight the controllers so the noise doesn't affect the bouncing until frame 201, and to turn off the position controller after frame 200.

Animate the weights:

Turn on Auto Key.
The Auto Key button turns red.
Move to frame 200.
You'll set keys at frames 200 and 201 for the Bezier Position. You'll also set keys at frames 200, 201 and 0 for the Noise.
Open the Position List rollout, then in the window select the Bezier Position layer.
Locate the Weight field, then Shift+right-click the spinner arrows.
The spinner is outlined in red, showing a keyframe has been placed there.

TipYou can set keys this way in both Set Key and Auto Key modes.
Select the Noise Position layer in the Position List rollout.
Right-click the spinner.
The Weight value is reset to 0, and a key is set.

TipRight-click any spinner to reset the value to 0 and set a key. Shift+right-click any spinner to add a key without changing the value.
Move to frame 201.
Tip You can use the . key on the keyboard to move ahead one frame at a time. You can also click the arrows on either side of the frame indicator on the time slider.
With Noise still selected, enter 100 in the Weight field,
In the Position List, select the Bezier Position layer, then right-click the Weight spinner to set the value to 0 and set a key.
This removes the bouncing from this point on.
In the animation playback controls, click Go To Start.
Select the Noise Position in the Position list, then set the Weight value to 0.
Play the animation.

Ball stops bouncing after frame 200, rolls around table

The Ping-Pong ball bounces across the table, then stops bouncing, but still rolls around a bit.
If for some reason the ball is rolling around in the air, instead of on the table, go to frame 201 and move the dummy object down until the ball comes into contact with the table. Use this technique to correct any other errant movement.
To stop the ball's movement altogether, go to frame 250 and keyframe the Noise weight to 0. Play the animation. The ball stops moving completely at frame 250.
Turn off Auto Key.
Save your work as mypingpong_layered_animation.max.
You can open pingpong_layered_animation.max to compare your work with a completed tutorial file.

Adding Squash and Stretch with Modifiers