Blender 3D is a free software capable of creating stunning animations. Most animations in Blender use so-called keyframes. This introduction to keyframing in Blender will cover everything you need to start animating!
Recommended: Use NSDT editor to quickly build programmable 3D scenes
1. What are key frames?
Before computers, animators had to draw each frame of an animation manually—making extremely minor changes between each image.
With keyframes in Blender (and other animation software) we tell the program how or where we want "something" to be at a certain point in time.
We then move to another point in time in the animation and tell Blender how "something" should exist. These two points in time are called "keyframes". Blender will calculate the animation for each frame between two keyframes.
Why do I say "something"? This is because animation keyframes can control a lot of things. They can control the position, shape and color of objects. Keyframes can control lighting conditions, fog, camera positioning, and nearly every other component of your animation.
2. Basic keyframe example
This is the most basic example of keyframe animation. Let's say we want the cube in the image above to move from the left to the right of the screen. We need to decide at which frame in the animation the cube will start moving. Second, we need to identify the frame where the cube stops moving.
In this example, we will have the cube start moving at frame 50 of the animation and stop moving at frame 100. We need to first go to frame 50 in the timeline. Make sure the cube is at the desired starting position and enter keyframes (I'll show you how in the next section).
We then need to go to frame 100 in the animation, move the cube to its end position and enter another keyframe.
We just told Blender that we want the cube to start at one location on frame 50 and end at another location on frame 100. Blender will calculate the cube's position on each frame (i.e. frame 51, 52, etc.).
Without keyframes, we would have to move the cube 50 times and render it at each position as it moves. Of course, there's a lot more to keyframe animation that needs to be covered.
3. Timeline Editor
Before we start adding keyframes, let's take a look at the Timeline Editor. In Blender's default workspace, the Timeline Editor is located at the bottom of the screen.
If you've ever used video editing software, this will look familiar. The most important part is that we understand how to move back and forth on the timeline and identify which frame we are currently in.
The current frame will appear in the Current Frame box and will be visually indicated by a vertical line with a highlighted number above it. In the example above, the timeline is at frame 1.
4. How to add position keyframes
Keyframes can be added to many things in Blender, but let's stick with the simple example of moving a cube around the screen. Here's how to add position keyframes to an object in Blender.
- Select the object we want to move. Make sure it's at the desired starting position, then go to the frame in the timeline where we want the motion to begin.
- Use the shortcut "I" key to insert keyframes. This will open up a long list of keyframe types to choose from. Since we are trying to animate changes in position, select "Position" from the menu.
- Alternatively, we can right-click and select "Insert Keyframe" from the context menu.
- Move to the point on the timeline where we want the object's movement to end.
- Move the object to where we want it at the end of the movement. With the object selected, use the shortcut "I" to add another keyframe. Select Position again as the keyframe type.
- Play the animation and make sure the object moves as desired.
Following these instructions will add two keyframes to the object. One is where the object starts moving, and one is where the object stops.
In the timeline, two diamonds will appear indicating where the keyframes will be placed. The diamond appears yellow when selected and white when unselected.
We can of course add additional keyframes to continue animating the motion and Blender will calculate the position for each frame between the keyframes.
5. Convert the value in the sidebar
When we add keyframes to an object's position, rotation, or scale, we are actually setting keyframes to the values of these transform properties.
In the sidebar under View, we'll see the color appear on the keyframe values.
We will discuss the meaning of these colors further.
6. Reverse direction
Suppose we want the cube to remain in its final position for another 50 frames (until frame 150), and then return to the left side of the screen at frame 200. We need to go to frame 150 and without moving the cube, add another position keyframe.
The purpose of this keyframe is to tell Blender that no movement should occur between the last keyframe and the current keyframe. When two adjacent keyframes display the same value, a line will appear between them in the timeline, indicating no change.
Then we'll go to frame 200, move the cube back to the left and add a position keyframe.
Adding a keyframe at frame 150 is easy to overlook, but it is important. Without it, the cube moves to the right and then immediately starts moving to the left.
7. Interpolation method
The calculation of motion or other changes between two keyframes is called "interpolation". There are different ways to interpolate animated features (again, not just position can be animated.)
You may have noticed that the cube starts moving slowly, then speeds up, then slows down when it comes to a stop? This is because the interpolation type is set to "Bezier", which slows down changes at the beginning and end of the motion.
Select one or more keyframes in the timeline (they are yellow when selected) and press "T" while hovering in the timeline. This will open a menu box to set the keyframe interpolation method for the selected keyframe.
Select Bessel interpolation
On the left are the three basic types of interpolation. The other two columns include additional effects that can be added to the interpolation, but we'll focus on the basics for now.
7.1 Constant interpolation
Constant interpolation does not change anything until the final keyframe is reached. For our cube, it doesn't move until frame 100, and then suddenly jumps to its end position.
This is rarely the type of interpolation we want to use.
7.2 Linear interpolation
Linear interpolation is a smooth and constant transition. The cube will move at the same speed from the start keyframe to the end keyframe. There are many uses for this feature (including looping animations), but a perfectly constant speed doesn't seem realistic for most actions.
7.3 Bezier curve interpolation
Bezier interpolation uses Bezier curves (discussed in detail in Graphics Editor) to make the animation start slowly. It then speeds up, but slows down again near the final keyframe.
This is a very common interpolation and is turned on by default. Very few (if any) things in the real world start and stop without speeding up and slowing down. Bezier interpolation can be extensively modified in the graphics editor to determine the size of the effect in the transition.
8. Change the default interpolation method
Blender will set a default interpolation method for each keyframe added. The default interpolation can be changed in Blender's User Preferences. Go to Edit - Preferences. Select the tab labeled "Animation" and find the default interpolation settings under "Function Curves".
9. Automatic keyframes
The auto-key feature in the timeline looks like a record button. Activating this feature will automatically set keyframes for any changes to the scene. This might be a very quick way to add keyframes, but...
Auto keyframe button in timeline
…we need to make sure we turn off autotyping when we’re done!
Otherwise, the keyframes will be placed where we don't want them and it will really mess up our entire project.
10. Delete and clear keyframes
In Blender we can delete individual keyframes or entire keyframe channels. To remove keyframes in Blender, right-click on the value with the keyframe to open the context menu. We see the option to delete or clear keyframes.
Delete will delete the current keyframe. Clearing a keyframe will delete all keyframes for that value.
11. Other transformation animations
As mentioned before, changes in an object's position are far from the only things we can animate using keyframes. Position, rotation and scaling are the three "transformations" of an object. They can all be keyframed in the same way.
11.1 Rotation animation
Rotation can be animated in the same way as object position. When adding keyframes, select "Rotation" as the keyframe type if we are only animating rotation. Additionally, "Position and Rotation" is a listed option where both position and rotation keyframes can be added.
11.2 Scale animation
In addition to position and rotation, you can also keyframe an object's scale in the same way. If all three transforms are keyframed together, you can select the Position, Rotation, and Scale option.
12. Set animation values in Blender
We can animate more than just the position, rotation, and scaling of objects. Almost anything that has a value displayed in the slider can be assigned a keyframe. By "slider" I mean the type of values shown in these images:
As you can see, almost anything we want to animate, can be done in Blender.
To add a keyframe to any value, make sure you are on the frame where you want to add the keyframe. Hover your cursor over the value and press "I". The value slider will turn yellow, indicating that the keyframe is active on the current frame.
You may also see the value slider highlighted in a different color.
An orange slider indicates that a keyframe is assigned at the current value, but the displayed value is different from the value indicated by the keyframe.
For example, if we have an existing keyframe at the cube's position, and we move the cube, the current keyframe will not be updated by default. Once we change the frame, the cube returns to the position indicated by the keyframe.
A green slider means that the value has a keyframe, but is not on the current frame of the animation.
13. Animation value example – light intensity
As an example of animating values in Blender, let's say we have the light in the image below and want it to increase in intensity between frame 30 and frame 90 of the animation.
We can do this by adding keyframes to the light power settings in the Light Properties Panel.
We'll go to frame 30 in the animation and set the power of the light to where we want it to start at intensity - let's start at zero power. Enter zero in the Value box. Hover your mouse over the box and press "I" on your keyboard. The box will turn yellow to indicate that there are keyframes on the current frame.
Next we'll go to frame 90 in the timeline. The value slider will turn green because there is a keyframe assigned to that value, but it's not on the current frame.
We change the light's power value to 1000. Again, we hover over the value and press "I" on the keyboard to add a second keyframe.
Now, if we play the animation, the intensity of the light will be zero until we reach frame 30. Then it will start to climb between frame 30 and frame 90. At frame 90, the light's intensity will reach 1,000 and remain there for the rest of the animation.
14. Graphic Editor and Dope Sheet
When learning animation in Blender, we eventually encounter the need for a graphics editor and a dope sheet. Along with the Timeline Editor, these are the three main animation editors.
Dope Sheet, Timeline and Graph Editor are the main animation editors in Blender
At first, they look similar. However, each tool does a different job than the others.
15. Graphics editor
The Graphics Editor displays all keyframes assigned in the Blender file and connects them with curves. These curves are called "f-curves" and graph any value over time.
Blender graphics editor
Time is represented from left to right in the graphical editor. Animated values are drawn vertically.
We can control a lot about animation using the graphics editor. Keyframes reveal handles, allowing us to change the shape of an f-curve, just like a Bezier curve in the 3D viewport.
Changes in direction and curvature affect how the animation is interpolated. We can also move the keyframes left and right to adjust their timing.
On the left side of the graphics editor we can see all active animation "channels". A Channel is a separate animation "thing". If we animate the position of an object, we actually create three animation channels - one for each axis (X, Y, and Z).
Channels are displayed in hierarchical order and can be expanded. Depending on the number of animated elements for a particular object or scene, there may be multiple layers of passes.
Channels can be individually renamed, hidden and further edited. Unused channels can be deleted if they are not needed. Channels also appear in the dope sheet.
15.1 Standardized graphics editor
Since the values of different animations can vary greatly, the graph in the graph editor may be too large or too small for us to use. If we highlight the function curve we want to focus on and press the Normalize button above the graph, Blender will resize the function curve plot appropriately.
The "Home" button on the keyboard is a shortcut to the standardized graphics editor.
15.2 Graphic Editor Modifier
In the graphical editor, we can open the sidebar by hovering the cursor and pressing "N" on the keyboard. The option to add modifiers to the function curve is available in the sidebar. Each modifier has a different effect on the function curve. Modifiers can be added to function curves even if only one keyframe is assigned.
15.3 Function curve noise corrector
The Noise modifier adds procedural noise to the f-curve. This is useful for getting random effects, for example when we want the light intensity to flash. Noise can be adjusted using the Scale and Strength settings in the modifier panel.
15.4 Function curve loop modifier
The Loop modifier causes selected keyframes to repeat in a loop. Before I knew this, I spent too much time copying and pasting keyframes unnecessarily.
15.5 Function Curve Limit Modifier
The Limit modifier adds limits to animation values. These limits can be placed on the X (time) or Y (value) axis. Each can have upper and lower bounds.
Modifiers can be stacked like object modifiers. For example, you could add a Noise modifier and then a Limit modifier as shown below.
16. Photography sheet
The Dope Sheet is another tool for seeing how keyframes are arranged throughout the scene.
Here we can align or offset keyframes and adjust the timing of the animation. While the main dope sheet displays an overview or "bird's eye view" of keyframes, specific types of keyframes can be viewed using different dopesheet modes (drop-down menu in the upper left corner).
17. Related animation topics
Blender's animation tools don't end with keyframes. More advanced topics include:
- The Non-Linear Animation (NLA) editor converts a sequence of keyframes into animated motion and allows them to be moved, combined, and manipulated, similar to how video clips are processed in video editing software.
- Character rigging is the process of adding a skeleton-like armature (or "rig") to a character. The rig is connected to the character using vertex groups. Individual bones in the skeleton will control different designated body parts and can be animated.
- Shape keys are tools for animating the deformation of meshes or curves. These are usually used for the muscles of characters and facial expressions.
18. Conclusion
Whether you're new to keyframe animation or have been animating in Blender for a while, I hope this article was helpful.
Original link: Blender keyframe animation tutorial—BimAnt