利用者:Jaredr122/Doc:2.6/Manual/Animation/Editors/Graph/FCurves

提供: wiki
< 利用者:Jaredr122
2013年2月3日 (日) 11:04時点におけるwiki>Jaredr122による版 (Created page with "{{Page/Header|2.5|Doc:2.5/Manual/Animation/Graph Editor|Doc:2.5/Manual/Animation/FCurve_Modifiers}} {{review|text= axis range}} = Working with F-Curves = Once you have created...")
(差分) ← 古い版 | 最新版 (差分) | 新しい版 → (差分)
移動先: 案内検索


Page status (reviewing guidelines)

Text axis range
Proposed fixes: none

Working with F-Curves

Once you have created keyframes for something, you can edit their corresponding curves. In Blender 2.5, IPO Curves have been replaced by F-Curves, however, editing these curves is essentially still the same.

The concept of Interpolation

When something is "animated," it changes over time. In Blender, animating an object means changing one of its properties, such as its X location, or the Red channel value of its material diffuse color, and so on, during a certain amount of time.

As mentioned, Blender's fundamental unit of time is the "frame", which usually lasts just a fraction of a second, depending on the frame rate of the scene.

As animation is composed of incremental changes spanning multiple frames, usually these properties ARE NOT manually modified frame by frame, because:

  • it would take ages!
  • it would be very difficult to get smooth variations of the property (unless you compute mathematical functions and type a precise value for each frame, which would be crazy).

This is why nearly all direct animation is done using interpolation.

The idea is simple: you define a few Key Frames, which are multiple frames apart. Between these keyframes, the properties' values are computed (interpolated) by Blender and filled in. Thus, the animators' workload is significantly reduced.

Example of interpolation

For example, if you have:

  • a control point of value 0 at frame 0,
  • another one of value 10 at frame 25,
  • linear interpolation,

then, at frame 5 we get a value of 2.

The same goes for all intermediate frames: with just two points, you get a smooth growth from 0 to 10 along the 25 frames. Obviously, if you’d like the frame 15 to have a value of 9, you’d have to add another control point (or keyframe)…

Interpolation and Extrapolation settings

F-curves have three additional properties, which control the interpolation between points, extension behavior, and the type of handles.

Interpolation Mode

You have three choices (T, or Curve » Interpolation Mode):

Constant
There is no interpolation at all. The curveconstantly have the value of its last keyframe, giving a discrete (stairway) “curve”. Very seldom useful.
Constant.


Linear
This simple interpolation creates a straight segment between each neighbor keyframes, giving a broken line. It can be useful when using only two keyframes and the Extrapolation extend mode, to easily get an infinite straight line (i.e. a linear curve).
Linear.


Bezier
The more powerful and useful interpolation, and the default one. It gives nicely smoothed curves, i.e. smooth animations!
Bézier.


Remember that some Fcurves can only take discrete values, in which case they are always shown as if constant interpolated, whatever option you chose.

Extrapolation

Extrapolation defines the behavior of a curve before the first and after the last keyframes.

There are two basic extrapolation modes, (⇧ ShiftE, or Channel » Extrapolation Mode):

Constant
The default one, curves before their first keyframe and after their last one have a constant value (the one of these first and last keyframes).
Linear
Curves ends are straight lines (linear), as defined by their first two keyframes (respectively their last two keyframes).


The two extensions available for Ipo curves.
Constant.
Extrapolation.


Additional extrapolation tools are located in the F-Curve Modifiers

Handle Types

There is another curve option quite useful for Bézier-interpolated curves. You can set the type of handle to use for the curve points V

Automatic
Keyframes are automatically interpolated
Auto handles


Vector
Creates linear interpolation between keyframes. The linear segments remain if keyframe centers are moved. If handles are moved, the handle becomes Free.
Vector handles


Aligned
Handle maintain rotation when moved, and curve tangent is maintained
Aligned handles


Free
Breaks handles tangents
Free handles


Auto Clamped
Auto handles clamped to not overshoot
Auto clamped handles


Direction of time

Although F-curves are very similar to Bézier curves, there are some important differences.

For obvious reasons, a property represented by a Curve cannot have more than one value at a given time, hence:

  • when you move a control point ahead of a control point that was previously ahead of the point that you are moving, the two control points switch their order in the edited curve, to avoid that the curve goes back in time
  • for the above reason, it's impossible to have a closed Ipo curve
Two control points switching: the curve can't go back in time!
Before moving the second keyframe
After moving the second keyframe


Curve Selection

By default, when you add keyframes to a channel, the Graph Editor displays them in Edit Mode. Just like in the 3D View, you can toggle the editability of a channel by pressing ⇆ Tab. In the Channel Box, the lock icon also toggles between edit and "non-edit" mode.

Selection Tools

You can select curve handles clicking LMB Template-LMB.png (or ⇧ ShiftLMB Template-LMB.png for multiple. You can select an entire key by selecting the center point, or just select one the handles

You can also (de)select all visible curves with A (or Select » Select/Deselect All), and do a border-selection with B (or Select » Border Select) – simple LMB Template-LMB.png click-and-drag to add to the selection, and RMB Template-RMB.png (or CtrlAltLMB Template-LMB.png) to remove from the selection.

Select All A
In edit mode, select/deselect all keyframes
In locked mode, select/deselect all visible channels
Invert Selection CtrlI
Inverts selected keys
Border Select B
Allows selection of keyframes within a region
Border Axis Range AltB
Axis Range...
Border (include Handles CtrlB
Include Handles, handles tested individually against the selection criteria
Columns on Selected Keys K
Select all keys on same frame as selected one(s)
Column on current Frame CtrlK
Select all keyframes on the current frame
Columns on selected Markers ⇧ ShiftK
Select all keyframes on the frame of selected marker(s)
Between Selected Markers AltK
Select all keyframes between selected markers
Before Current Frame [
Select all keys before the current frame
After Current Frame ]
Select all keys after the current frame
Select More Ctrl+ NumPad
Grow keyframe selection along Fcurve
Select Less Ctrl- NumPad
Shrink keyframe selection along Fcurve
Select Linked L
Selects all keyframes on Fcurve of selected keyframe


Editing Curves

Transformations

Transform properties

You can grab (G), rotate (R) and scale (S) the selected curves (those visible, with white control points/keyframes) – operations also available from the Curve » Transform sub-menu.

Additionally, for translation and scaling, you can lock the transformation along the X (time) or Y (value) axis, as usual by hitting X or Y during transformation.

Transform Properties

For precise control of keyframe position and value, you can enter values in the Active Keyframe section of the Properties Panel.

Snapping

You also have the classic “transform snapping” features: holding Ctrl while transforming will snap it to one-frame/one-value steps, while holding ⇧ Shift will slow down the movement, increasing its precision. Note however that using ⇧ ShiftCtrl just slows down the movement, without reducing the snapping steps.

(⇧ ShiftS or Key » Snap) You can snap keyframes in several ways:

Current Frame
This option will move all selected keyframes to the currently active frame.
Cursor Value
This option will move the selected keyframes to the current position of your 2d cursor in the graph editor.
Nearest Frame
This will horizontally (timely) move all keyframes of the selected curves to their nearest frame (e.g. a keyframe defined at frame 23.2 will be moved at frame 23).
Nearest Second
This will horizontally (timely) move all slected keyframes of the selected curves to their nearest full second (e.g. a keyframe between 00:02 and 00:03 seconds will move to either 00:02 or 00:03 depending on which is nearer).
Nearest Marker
This will horizontally (timely) move all keyframes of the selected curves to the marker nearest to them (see also Markers).
Flatten Handles
This is only useful with the default F-curves: it will rotate all control points of the selected curves to set them horizontal.
“Flatten Handles” snapping example.
Before Flatten Handles.
After Flatten Handles.


Auto-snap

Auto snap is another way of constraining keyframe position. The selection box in the header allows you to set how keyframes behave when you move them

Nearest Marker
Snap x-axis to marker positions
Nearest Frame
Snap to frames (default)
Time Step
Snap to 1.0 frame/second intervals
No auto-snap
Disable auto snapping


Copying

You can copy one or more keyframes into a buffer, and then paste them into the same curves. This is done through two header buttons:

  • The “copy” CtrlC button (down arrow) copies the selected and visible curves into the buffer.
  • The “paste” CtrlV button (up arrow) pastes the buffer content into the corresponding visible curves of the current channel.

Note that this tool is not working (even though available) in “keyframe” mode. And in edit mode, only the selected points are copied/pasted (not the whole curve…).

You can also Duplicate keys through the Key menu.


Deleting

To delete a keyframe, select it (in “default” mode), and hit X (or use Curve » Delete).


Mirror

You can mirror the selected curves (⇧ ShiftM or Curve » Mirror), either Over Current Frame (i.e. the green cursor), Over Vertical Axis (i.e. frame 0), or Over Horizontal Axis (i.e. value 0.0).

Cleaning

O (or Curve » Clean Keyframes menu entry) Cleaning keyframes resets keyframe tangents to theier auto-clamped shape, if they have been modified.

Fcurve before cleaning
Fcurve after cleaning


Smoothing

(AltO or Curve » Smooth Keys) There is also an option to smooth the selected curves , but beware: its algorithm seems to be to divide by two the distance between each keyframe and the average linear value of the curve, without any setting, which gives quite a strong smoothing! Note that the first and last keys seem to be never modified by this tool.

Fcurve before smoothing
Fcurve before smoothing


Sampling and Baking Keyframes

Sample Keyframes ⇧ ShiftO
Sampling a set a keyframes replaces interpolated values with a new keyframe for each frame.
Fcurve before sampling
Fcurve after sampling


Bake Curves AltC
Baking a curve replaces it with a set of sampled points, and removes the ability to edit the curve.