The Introduction and F-Curve Interpolation part of this page was originally written by Jaredr122 2011.
Then modified by a set of users.

Animation Tools: Channels

I am a bit lost how to write this.

Funny Actions

bpy.data.actions['CubeAction'].groups['Location'].channels[0].keyframe_points[2].interpolation='LINEAR'

Action: An action holds a set of animation data for an object.
Group: A group of channels, example, location, rotation.
Channel: A property of an object that can be animated. These are what have FCurves. They are like Drivers.
Keyframe: An FCurve control point.

Channels

>>> bpy.data.objects['Cube'].animation_data.drivers[0]
bpy.data.objects['Cube']...FCurve

>>> bpy.data.actions['CubeAction'].groups['Location'].channels[0]
bpy.data.actions['CubeAction']...FCurve

Channels

Graph Editor: Channel F-Curve.

Channels have an F-Curve which is used to animate objects.

Channels use time to control the values of properties.

Using a F-Curve, the channel reads the time frame and sets the value of the property.

So from this example, if the time frame is 2.0 the property will be 0.5.

Introduction

Keyframes are one of the main objects used for animation. Keyframes define a value of data at a specified frame.

Keyframes.

Quite obviously, something is "animated" when it changes over time. In Blender, animating an object means changing its properties over time, such as its X location, or the Red channel value of its material diffuse color, and so on.

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.

F-Curve Interpolation

As animations are 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 a smooth variation of the property.

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

The idea is simple: you define a few “control points”, called "keyframes", which are multiple frames apart.

Example of interpolation

Between these keyframes, the properties values are interpolated, allowing for a smooth transition between keyframes. Thus, the animators' workload is significantly reduced.

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)…

These F-Curves can be edited in the Graph Editor.

Adding Keyframes

Here are some common ways to animate objects by adding keyframes.
These methods can be used on different objects, like armature bones in pose mode.

Insert Keyframe

Add keyframe to Cube.

Keyframes in the Timeline.

In the Timeline Editor, move the green frame cursor to 0, by pressing or holding LMB .

With a Mesh Object selected in Object Mode, and the frame set in the Timeline. In the 3D View Tools press the 'Insert Keyframe' button, or press I in the 3D View to bring up the 'Insert Keyframe Menu'.

Select 'Location', this will record the location of the Mesh Object on the frame the Timeline cursor is set.

Set the Timeline cursor to a different frame, move the Mesh Object, then insert another keyframe.

The keyframes are displayed in yellow on the Timeline. Move the Timeline cursor to test the animation.

Keying Sets

Timeline Keying Sets.

Keying Sets are a set of keyframes in one. They are made to record multiple properties at the same time. There are some built in keying sets, and also custom keying sets.

Use the keying set menu in the Timeline editor, to select a keying set. Now when you insert a keyframe, blender will add keyframes for the selected keying set.

See Timeline for more info.
See Keying Sets for more info.

Auto Keyframe

Timeline Auto Keyframe.

Auto Keyframe is the red record button.
Auto Keyframe adds keyframes automatically to the set frame after setting the location, rotation, scale, etcetra, of the selected object in the 3D View.

See Timeline for more info.

Properties

Timeline Keying Sets.

Keyframes can be used to animate lots of properties in blender.
To add keyframes to a property on the UI, RMB the property, then select Insert Single Keyframe, or Insert Keyframes.
Insert Keyframes will add a keyframes to the set of properties.

Keyboard

The keyboard can also be used to add keyframes.

I: Insert keyframe to the set frame.

Alt+i: Remove keyframe from the set frame.

Alt+shift+i: Remove all keyframes from the UI property.

Animation Editors

Most of the low level settings for the keyframes are found in the Graph Editor.
You can add keyframes to channels that have existing keyframes in several animation editors, which are described in other pages

Ex Links

Motion Paths - M
Graph Editor - M
Graph Editor - M - User Doc 2.5
Timeline - M

利用者:Koilz/wiki - doc kia - Keyframes

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