The Fcurve (Function Curve) window is where function curves are displayed and edited. Each displayed function curve is listed in a scroll box in the upper-right corner of the window, and the selected function curve appears white (by default).

A function curve is displayed by choosing the Motion module's FcrvSelect menu cell and one of its commands (starting on FcrvSelect->Clear).

There are two zoom operations designed especially for use in the Fcurve window:

• To zoom in on the x-axis of the window (the number of frames), hold down the z and x keys simultaneously and follow the mouse directions in the status bar.
• To zoom in on the y-axis of the window (the values), hold down the z and s keys simultaneously and follow the mouse directions in the status bar.

The Fcurve window includes a title bar containing various options with which you can edit the displayed function curves. If you use the quarter-view or portrait-view and not the default landscape view, some options in the menu bar are not visible.

For more information on editing function curves, see Editing an Animation in the Animating User's Guide,

This section describes the title bar options that are specific to the Fcurve window, but for the other standard title bar options available, see Window Title Bar Options.

Note:

The number of options available from the title bar and the order in which they are displayed depends on the resolution of your machine. Low resolution (1024) machines do not show the CPTAG (Copy Tagged Keys) option.

CPTAG

This option allows you to copy, delete, or paste tagged key points. Selecting it is the same as choosing the FcrvEdit->Copy/Paste Tagged Keys command.

• The left mouse button copies the tagged key points to a buffer.
• The middle mouse button removes the tagged key points and copies them to a buffer.
• The right mouse button pastes the tagged key points that are cut or copied to the buffer at the selected insertion point.

SLOPE

This option sets the relationship between the left and right slope of key points when the function curve interpolation mode is set to Spline (the default). Selecting this option is the same as choosing the FcrvEdit->Slope Management command or pressing the s Supra key. The mouse buttons are configured so that:

• The left mouse button unifies the two slopes, giving the smoothest possible transition at key points for any given position of the slopes. To set the key point to unify, click on it with the left mouse button.
• The middle mouse button breaks the two slopes, allowing control of the tension on each slope separately. To set the key point to break, click on it with the middle mouse button.
• The right mouse button releases the two slopes. Slopes are unified and their positions are recalculated to give the smoothest curve. Dotted lines identify when a slope is released. To set a key point to release, click on it with the right mouse button. This is the default mode for the key points.

INTERP

This option sets the interpolation mode for each segment of the function curve. Selecting this option is the same as choosing the FcrvEdit->Interp Management command or pressing the i Supra key. The mouse buttons are configured so that:

• Left-clicking the key point sets the segment (to the right of the key point) to spline interpolation.
• Middle-clicking the key point sets the segment to linear interpolation.
• Right-clicking the key point sets the segment to constant interpolation.

See Function Curve Interpolation Types for more information.

SNAP

Each function curve has a corresponding auxiliary curve that is shown in dotted lines in the Fcurve window. This lets you keep a "copy" of the original function curve as you are modifying it. With the SNAP option, you can take a "snapshot" of the current function curve's shape. When you edit the function curve, this snapshot remains as the auxiliary function curve. Using these snapshots as a visual reference, you can edit your function curve progressively. If you want to return to the auxiliary function curve at any time, select the SWAP option.

Selecting the SNAP option is the same as choosing the FcrvEdit->Snapshot Fcurve command.

Note:

Some of the function curve commands do an automatic snap. FcrvEdit commands such as FcrvEdit->Fit Spline to Fcurve, FcrvEdit->Expression, and FcrvEdit->Convert to Raw Fcurve all involve modifications to the entire function curve and an automatic snap.

SWAP

This option lets you return to the previous SNAP version of your function curve (the auxiliary function curve), which is shown in dotted lines. This is a very useful feature for experimenting with different modifications on a function curve. It is essentially a way of "undoing" an edit to return to an earlier version.

When you click SWAP, the auxiliary function curve is swapped with the currently selected function curve. If you click this option again, the two curves are swapped again.

Selecting this option is the same as choosing the FcrvEdit->Swap Fcurve command.

SETKEY

This option allows you to numerically edit a function curve with a dialogue box. Selecting this option is the same as choosing the FcrvEdit->Edit Fcurve command.

EDITKEY

This option allows you to edit key points on the selected function curve. Selecting this option is the same as choosing the FcrvEdit->Edit Key Point command.

• To move a key point, pick a point with the left mouse button and drag the mouse to move the point. The function curve is modified accordingly and the x and y values are displayed dynamically in the status line. You can also use the left mouse button on a slope handle to modify the function curve's slope around the associated keyframe.

Note:

Keyframe key points (shown in yellow) cannot be moved. These are keyframes in which you have selected the SETKEY option or the FcrvEdit->Set Key command and set the keyframes to be of Keyframe type.

• To insert a key point, move the cursor to the desired location on the function curve in the Fcurve window. Click the middle mouse button: the key point appears. Hold the button and drag to fine-tune the shape of the curve. When satisfied, release the button.

Tip:

To insert a key point directly on the function curve without modifying its shape, hold the Shift key and middle-click where you want a key point.

• To remove a key point, click on the key point with the right mouse button.

EDITTAG

This option allows global editing on key points of the function curve. Selecting this option is the same as choosing the FcrvEdit->Edit Tag Key Points command. The mouse buttons are configured so that:

• The left mouse button translates tagged key points.
• The middle mouse button scales key points on the x-axis.
• The right mouse button scales key points on the y-axis.

EDITFCV

This option allows global editing of the function curve. This includes translation (offset) and scale.

Note:

You can also translate and scale key points on the function curve using the Trans and Scale menu cells, in which case the changes in scale are from zero.

Selecting this option is the same as choosing the FcrvEdit->Edit Fcurve command. The mouse buttons are configured so that:

• The left mouse button translates the function curve. Click any key point and drag the function curve to offset it in x (frames) or y (movement amplitude).
• The middle mouse button scales the function curve on the x-axis (frames). If you click on the first key point, all the key points scale to the last key point. If you click on the last key point, all the key points scale to the first key point. If you click on any key point between the end key points, they scale toward end key points without exceeding them.
• The right mouse button controls the scaling on y (movement amplitude). It works the same as for end key points, but with in-between key points, it scales all the key points according to the average value.

These interpolation types show the different way a function curve's slope is interpolated between key points. Other Fcurve commands that cannot be accessed with these title bar options can be accessed from the FcrvCopy and FcrvEdit menu cells. For more information, see these commands starting on FcrvCopy->Object.

CON

This option controls the interpolation between key points on a function curve by repeating the value of a keyframe for each of the frames after it. The movement is characterized by sudden changes and then static positions. Selecting this option is the same as choosing the FcrvEdit->Interp Mode->Constant command.

LIN

This option creates regular intervals between key points making each segment of the function curve appear as a straight line. The movement is characterized by sudden changes at each key point. Selecting this option is the same as choosing the FcrvEdit->Interp Mode->Linear command.

SPL

This option is the default interpolation. It uses a spline interpolation between key points showing an acceleration and a deceleration according to the slopes at the key points. This results in a smooth transition of motion at the key points. Acceleration and deceleration can be controlled with the FcrvEdit->Edit Key Point and FcrvEdit->Slope Management commands. Selecting this option is the same as choosing the FcrvEdit->Interp Mode->Spline command.

SLO

The Slope 0 interpolation option creates a type of slope that allows you to constrain some or all keyframes of a function curve to a slope of 0. The tangent handles of the keyframes all remain horizontal (that is, with a slope of 0).

Selecting this option is the same as choosing the FcrvEdit->Interp Mode->Slope 0 command.

PLA

The Plateau option automatically sets the slope of a keyframe to zero if the next key point has the same value, or if that key point is a local minima or maxima. A local minima/maxima is a key point where both previous and next key points have either smaller (maxima) or larger (minima) values.

This is very useful for automatically preventing function curves from going above or below key points (and exceeding a pause value) instead of having to edit the slopes manually.

The Plateau option is usually used to create a pause in the motion. The two key points with the same value are interpolated by having horizontal slopes.

Selecting this option is the same as choosing the FcrvEdit->Interp Mode->Plateau command.

Last updated 03-apr-1998