Curve Editor

What is it all about? The ability to see and edit the interpolation between keyframes.

Keyframes are represented by little boxes.

The values between keyframes are represented by function curves, also known as fcurves.

You can switch between dope sheet and track view. Try this, and see how the 2 views of the same animation relate.

The curve editor is where you refine your animation.

To see a curve, you have to select a track [in the default setting.] In Max 4, turn on the Function Curves button.

To select multiple curves, use the Ctrl key.

The higher a value, the higher on the curve is a key. Try this by animating position on X.

Time is represented left to right, same as the dope sheer and track bar.

Flat lines indicate an object is motionless.

Steep curves indicate rapid animation.

Colors of function curves:

X = red

Y = green

Z = blue

[same as transform gizmos and world coord. tripod]

Selected keys are white [same as dope sheet]

Use the move keys button in the graph editor to select, move, delete, copy keys.

Tangents

This is a critical skill to learn to master animation. This is how you control interpolation between frames.

Auto tangents are the default assignation [Max 5] ... Smooth in Max 4.

Most often, you change them to Bezier, so you can access the Bezier handles to manipulate the curve. This is the most commonly used and most useful curve.

Fast tangents cause interpolated values to change quickly as the curve approaches the keyframe.

Fast in, fast out ... notice the relatively steep curve in an out of the white box:

Slow does the opposite ...

This curve is going slow into, and slow out, of the selected key; note the curve is less dramatic.

Step tangents have no interpolation expect a sort of on/off transition. Objects appear to jump from key to key. Can be used to turn lights on and off.

This interpolation of a light going on and off would appear as a gradual dimming and brightening:

Changed to step, the lights now switch on and off immediately:

Linear tangents are great to get down to the immediate, robotic, movement you see in machines, etc. The velocity is constant.

Smooth tangents make a nice smooth curve, without the handles of Bezier. This is where the problem of overshooting comes in, corrected in Max 5 with default settings to Auto tangents.

In and Out curves

Each keyframe has an incoming and outgoing curve. Experiment with selecting a few keyframes and changing the tangents in and out using the key tangents toolbar.

In max 5 you can use the flyout to set the incoming or outgoing curve only:

Right click a key to edit the curve’s in and out, value, etc:

Bezier Curve editing

In Max 5, the default is Auto ... as soon as you edit a bezier handle, it is converted to Bezier.

A Bezier curve:

I move up the outgoing to accelerate, and the incoming also change:

If I did not want that, I could hold down the shift key for this. this is unlocking or breaking the handles.

If I find later that was all a mistake, I need to reset the key to Auto:

But it is still “broken” or unlocked ... to fix that, right click on the key, and open up ... I need to do 2 things ...

1. convert back to Bezier in and out

2. re-lock the handles with the little padlock icon

Now they work like this again [locked]:

Note— free handle also unlocks key handles ... make sure the padlock is unlocked:

Lab Activity

1. Make a ball bounce all over the place. Manipulate the curves so the animation looks great. Use fast in, fast out, slow in, etc., to make the bouncing ball look real.

2. Make a light go on and off using Step.

3. Make a robotic movement of a primitive using linear.