Blender 2.5 Character Animation Cookbook
50 great recipes for giving soul to your characters by building high-quality rigs
Adjusting and tracking the timing
Timing, by itself, is a subject that goes well beyond the scope of a simple recipe. It is, in fact, the main subject of a number of animation-related books. Strictly speaking, Timing in animation is how long it takes (in frames or seconds) between two Extreme poses.
You can have your character in great poses, but if the timing between them is not right, your shot may be ruined. Maybe it is a difficult thing to master because there are no definite rules for it: everyone is born with a particular sense of timing. Despite that, it’s enormously important to look at video and real life references to understand the timing for different actions.
Imagine a tennis ball falling to the ground and bouncing. Think of the time between its first and second contact with the ground. Now replace it with a bowling ball and think of the time required for this bounce. You know, from your life experience, that the tennis ball bounces slower than the bowling ball. The timing between these two balls is different. The timing here (along with spacing, subject of the next recipe) is the main factor that makes us perceive the different nature and weight of each ball.
The “rules” of timing can also be broken for comedic effect: something that purposely moves faster or slower than usual may get a laugh from the audience. We’re going to see how different timings can change how we perceive a shot with the same poses.
How to do it…
- Open the file 007-Timing.blend (Go to Support to get the code). It has our character Otto with three poses, making him look from one side to the other:
(Move the mouse over the image to enlarge it.)
- Press Alt + A to play the animation. You may think the timing is acceptable for this head turn, but this method of checking the timing is not ideal. When you tell Blender to play the animation through Alt + A, you’re relying in your computer’s power to process all the information of your scene in real time. You’d probably end up seeing something slower than what you’ll actually get after rendering the frames.
When playing the animation inside the 3D view, you can see the actual playback frame rate on the top left corner of the window. If it’s slower than the scene frame rate (in this case, 24 fps), it means that the rendered animation will be faster than what you’re seeing.
When adjusting the timing, we must be sure of the exact results of every keyframe set. Even a one-frame change can make a huge impact on the scene, but rendering a complex scene just to test the timing is out of the question, because it just takes too long to see the results. We need a quick way to check the timing precisely.
Fortunately, Blender allows us to make a quick “render” of our 3D view, with only the OpenGL information. This is also called “playblast”, and is exactly what we need. Take a look at the header of our 3D view and find the button with a clapperboard icon, as seen in the next screenshot:
OpenGL stands for Open Graphics Library, and is a free cross-platform specification and API for writing 2D and 3D computer graphics. Not only are the objects inside Blender’s 3D view made using this library, but also the user interface with all its buttons, icons, and text are drawn on the screen with OpenGL. From OpenGL version 2.0 it’s possible to use GLSL, a high level shading language heavily used to create games and supported by Blender to enhance the way objects are displayed on the screen in real time. From Blender 2.5, GLSL is the default real time rendering method when the user selects the Textured viewport shading mode, but that option has to be supported by your graphics card.
- Click on that clapperboard button, and the active 3D view will be used for a quick OpenGL render of your scene. This preview rendering shares the Render panel settings in the Properties window, so the picture size, frame rate, output folder, file format, duration, and stamp will be the same. If you can’t see the button in your 3D View header (it is available only in the header) it may be an issue of lack of space; you can click with the middle button (or the scroll wheel) of your mouse over the header and drag it to the sides to find it.
- After the OpenGL rendering is complete, press Esc to go back to your scene and press Ctrl + F11 to preview the animation with the correct frame rate to check the timing.
Starting with the Blender 2.5 series, there’s no built-in player in the program, so you have to specify one in the User Preferences window (Ctrl + Alt + U), on the File tab. This player can even be a previous version of Blender in the 2.4 series or any player you wish, such as DJV or Mplayer. With any of these options you must tell Blender the file path where the player is installed.
Now that you can watch the animation with the correct frame rate, you’ll notice that the head turns quite fast, since it only takes five frames to complete. This fast timing makes our action seem to happen after the character listens to an abrupt and loud noise coming from his left, so he has to turn his head quickly and look to see what happened.
Let’s suppose our character is watching a tennis match in Wimbledon, and his seat is in line with the net, at the middle of the court (yep, lucky guy). Watching the ball from the serve until it reaches the other side of the court should take longer than what we have just set up, so let’s adjust our keyframes now. - In the DopeSheet window, leave the first keyframe at frame 1. Select the last column of keyframes by holding Alt and right-clicking on any keyframe set at frame 5. Move (G) the column to frame 15 (hold Ctrl for snapping to the frames), so our action takes three times longer than the original.
Another way of selecting a column of keyframes is through the DopeSheet Summary option on the window header. It creates an extra line above all channels. If you select the diamond on this line, all keyframes on that column will be selected. You can even collapse all channels and use only the DopeSheet Summary to move the keys along the timeline to make timing adjustments easily.
- Now, the Breakdown, or intermediate position between two Extreme poses. It doesn’t have to be at the exact middle of our action. Actually, it’s good to avoid symmetry not only in our models and poses, but in our motions too. Move (G) the Breakdown to frame 6, and you’ll have something similar to the next screenshot:
Now you can make another OpenGL render to preview the action with the new timing. You can choose to disable the layer where the armature is located, the second, by holding Shift and clicking over it, so you don’t have the bones on the preview. Of course this is far from a finished shot: it’s a good idea to make the character blink during the head turn, add some moving holds, animate the eyeballs, add some facial expressions, and so on. This rough example is only to show how drastically the timing can change the feel of an action. If you set the timing between the positions even higher, our character may seem like he’s looking at something slower (someone on a bike, maybe?) moving in front of him.
How it works…
Along with good posing, the timing is crucial to make our actions vivid, believable, and with a sense of weight. The timing also is very important to help your audience understand what is happening in the scene, so it must be carefully adjusted. To have a precise view of how the timing is working in an action within Blender, it’s best to use the OpenGL preview mode, since the usual Alt + A shortcut to preview the animation inside the 3D View can be misleading.
There’s more…
Depending on the complexity of your scene, you can achieve the correct frame rate within the 3D view with Alt + A. You can disable the visibility of irrelevant objects or some modifiers to help speed up this real time processing, like lowering (or disabling) the Subdivision Surface modifier and hiding the armature and background layers.
Spacing: favoring and easing poses
The previous recipe shows us how to adjust the timing of our character’s actions, which is something extremely important to make our audience not only understand what is happening on the screen, but also know the weight and forces involved in the motion. Since timing is closely related to spacing, there is often confusion between the two concepts.
Timing in animation is the number of frames between two Extreme poses. Spacing is how the animated subject moves and shows variations of speed along these frames. Actions with the same timing and different spacing are perceived differently by the audience, and these principles combined are responsible for the feeling of weight of our actions.
We’re going to see how the spacing works and how we can create eases and favoring poses to enhance movements.
How to do it…
- Open the file 007-Spacing.blend. It has our character Otto turning his head from right to left, just like in the timing recipe. We don’t have a Breakdown position defined yet, and this action has a timing set to 15 frames.
First, let’s understand the most elementary type of spacing: linear, or even spacing. This is when the calculated intermediate positions between two keyframes have the same distance among them, without any kind of acceleration. This isn’t something we’re used to seeing in nature, thus it’s not the default interpolation mode in Blender. - To use it, select the desired keyframes in a DopeSheet or a Graph Editor window, press Shift + T, and choose the Linear interpolation mode. The curves between the keyframes will turn into straight lines, as you can see in the next screenshot showing the channels for the Head bone.
If you preview the animation with Alt + A, you’ll see that the movement is very mechanical and unappealing, something we don’t see in nature. That’s why this interpolation mode isn’t the default one. Movements in nature all have some variation in speed, going from a resting state, accelerating to a peak velocity, then slowing down until another resting state. These variations of speed are called eases, and are represented with curved lines on the Graph Editor. When there is an increase in speed we have an ease out. When the movement slows down to a resting state, we have an ease in.
- This variation in speed is the default interpolation method in Blender, and you can enable it by selecting the desired keyframes in a DopeSheet or Graph Editor window, press Shift + T and select the Bezier interpolation mode. The next screenshot shows the same keyframes with easing:
When we adjust the curve handles on the Graph Editor, we’re actually defining the eases of that movement. When you insert keyframes in Blender, it automatically creates both eases: out and in (with same speeds). Since not all movements have the same variation of speed at their beginning and end, it’s a good idea to change the handles on the Graph Editor. This difference of speed between the start and end keyframes is called favoring.
When the Spacing between two poses have different eases, we say the movement “favors” one of the poses, notably the one which has the bigger ease. In the next screenshot, the curves for the Head bone were adjusted so the movement favors the second pose. Note that there is a softer curve near the second pose, while the first has sharper lines near it. This will make the head leave the first pose very quick and slowly settle into the second one.
In order to create sharp angles with the handles in the Graph Editor window, you need to select the desired curve channels, press V and choose the Free handle type.
- Open the video file 007-Spacing.mov in a video player, which enables navigating through the frames (such as DJV), to watch the three actions at the same time. Although the timing of the action is unchanged, you can clearly notice how the interpolation changes the motion. In the next screenshot, you can see that at frame 8, the Favoring version has the face closer to the second pose:
Now that you understand what spacing is, know the difference between the interpolation types, and can use eases to favor poses, let’s add a Breakdown position. This action is pretty boring, since the head turn happens without any arcs. It’s a good idea to tilt the head down a little during the turn, making an imaginary arc with the eyes.
Especially during quick head turns, it’s a good idea to make your character blink during the turn. Unless your character is following something with the eyes—such as in a tennis court in our example—a quick blink is useful to make a “scene cut” in our minds from one subject to the other.
- On the DopeSheet window, in the Action Editor, select the Favoring action. Go to frame 6, where the character looks to the camera. Select and rotate (R) the Head and Neck bones to front on their local X axis, as seen in the next screenshot, and insert a keyframe (I) for its rotation:
Since Blender automatically creates symmetrical eases on each new keyframe, it’s time to adjust our spacing for the Head and Neck bones on the Graph Editor window. If you play the animation with Alt + A, you’ll notice that the motion goes very weird because of that automatic ease. The F-Curves on the X axis of each bone for this motion are not soft. Ideally, since this is a Breakdown position, the curves between it and its surrounding Extreme poses should be smooth, regardless of the favoring.
- Select the curve handles on frames 1 and 6, and move (G) them in order to soften the curve peak in that Breakdown position. The next screenshot shows the curves before and after editing. Notice how the peak curves at the Breakdown in the middle get smoother after editing:
Now the action looks more natural, with a nice Breakdown and favoring created using the F-Curves. The file 007-Spacing-complete.blend has this finished example for your reference, in which you can play the animation with Alt + A to see the results.
How it works…
By understanding the principle of Spacing, you can create eases and favoring in order to create snappy and interesting motions. Just like visible shapes, the pace of motion in nature is often asymmetrical. To make your motions not only more interesting but also more believable and with accents to reinforce the purpose behind the movements, you should master Spacing. Be sure to check out the interpolation curves in your animations: interesting movements normally have different eases between two Extreme positions.
