General requirements for all character rigs

Beside the special requirements for creating “cartoony” animation, there are general requirements that all character rigs should have.

1.The rig should be as simple as they could.

It is important to limit the amount of controls that the animator can work with, do not overwhelm the computer and the animation with the extra feature which is not necessary. Animators have to work with fast updated and respond computer to check the animation, put out all the control and feature we don’t need can save the resource of computer. In the case of Maya, instead of using expression, I tend to use others each as set driven key and utility node, expression will slow down the computer as it will evaluate every time we change the parameters.

2.Controls should be unique and make immediate sense.

Animators have to due with a mass of control; them will be confused and spend time to find out what they want if every single control appears the same. Controls should be unique and understandable looking for intended use.

3.Animators can only select what need to be animate

Animators always select and moving object which an untouchable, it may damage the rigging system and cannot be recover after animated. Lock and hide those objects before the animation process.

4.Clarity

All the objects and controls shoulder named correctly and understandable, animators and other rigger will be searching by the name of objects. And a messy scene will make it more difficult for others to modify and further develop, delete all the objects or node which is not necessary, try to optimize the scene after the rigging process.

Rig requirements had defined

After analyze of the character and define what has to do in the animation, the rig requirements had defined:

1. In order to keep the motion of limb in from of arc, we will need the Forward Kinematics for general gesturing and in-between. Other times characters will place their limbs on the ground on some other object. In these cases, we want to make sure the limbs are locked off, we will use Inverse Kinematics. The IK and FK system has to been switchable anytime and anywhere in the character rig.

1. The arm should be able to rotation independent form the upper joint in the skeleton system, in order to create overlapping action with any counter animation has to create.

2. It is necessary to squash and stretch both the torso and the limbs in order to get exact pose in animation require. Thus, we intended to make all part of character squashing and stretching independently.

3. Beside the main skeleton for the movement and pose, extra deformation controls are required for creating exaggerative the line of action and for clarify the silhouette.

4. In order to create exaggerative facial express, the face will not be only driven by morphing. The head of character will be broken down in different parts; each will be driven by the IK control independently. A sort of on face control will be created which will stick on the face of character even though the facial has been driven by the others control, animators can tweak the facial expression by those control easily and directly.

5. The shoulder and hip should be allowed to move independently, so animators do not have to counter animation the shoulder after moving the hip. At the same time, Forward Kinematics control has to be preserved for the spine, thus, arc movement of the upper torso can be easily made.

6. Some extra deformers will be approximately placed at the end of limbs and head; animator can create the illusion of smear to reveal the fluency of motion and sense of speed.

Animatic

The rigs must be able accommodate those principles in order to give the animator to animate without limiting their creative idea. Meanwhile, the animatic was created, it gives a better idea of how the character will look and feel with motion and timing. That is another significant reference for both animation and the character rig.

Rig design process Part 6 Arc

The difference between the IK and FK

In real life, organic creatures always move in arcs or a sort of figure “8”. Our hands move naturally in arcs when we gesture or when we are just swinging them at our sides. Our hips move up and down in arcs as we walk. When you rotate a joint in a 3d program, it will actually naturally move through an arc, just as that joint would move in real life. Sometimes we don't want the lower nodes in a hierarchy to move with the upper nodes. You could manually go frame by frame and animate the joints keep in the some position but that is extremely tedious. Instead, you can set up an Inverse Kinematics chain that will lock joint and figure out the calculations you. However, there will also be no arc to the motion of an IK control, it moves linearly between poses. Where you naturally have an arc in the FK control, you will have to add arcs manually in the one with IK.

Rig design process Part 5 Follow through and Overlapping

The overlapping on the nose and head and the broken joint


Parts of characters does not move all at once, but instead it stretch, catches up, twists, turns, and contracts as the forms work against each other,. As one part arrives at the stopping point, others may still be in movement. The loose flesh on a figure, such as cheeks, will move art a slower speed than the skeletal parts. The most obvious example of overlapping action is the “broken joints”, to get some flexibility in limbs swing; we will break or bend the elbow or knee joint. It looks more natural even though it is against the anatomical limitation. The lack of control when we animate with inverse kinematics may make it more difficult to get it into the exact position you want. It is significant if we can switch between IK and FK to animate according to situation of the characters.

Rig design process Part 4 Staging

Character is bended to emphasize the “line of Action”

The silhouette doesn’t reveal what is happening with the character

The silhouette should be clear enough to help audience get the idea

Staging is about the presentation of idea from the characters; silhouette and line of action are two significant elements underneath that principle. Good staging in your camera view will allow audience to clearly and quickly understand what is going on in scene. It is important to keep in mind that we are still working with two dimensional projected images, even though we animate the rig and model in the three dimensional environments. A strong Silhouette is mostly important in “cartoony” animation; pose and animation should be very clean to audience to make a stronger statement. Line of action shows the direction of movement of the main mass of the character, line of action should not be straight, curve and arc for the line of action shows the direction and the fluency of action, that kind of rubber hose limb and body is against the idea of joints. Under the necessity, the rigs are rigid; we cannot bend the character for the smooth curve line of action. We have create some extras for bending the character which have to be driven by the originally rig.

Rig design process Part 3 Exaggeration

Exaggerated pose advanced the “cartoony” style



In the “cartoony” animation, exaggeration is pushed something beyond what you think is natural and realistic, it helps achieve a stronger dramatic or comedic effects, is a useful way to emphasize the emotion or humor. The more exaggerated your animation, the more “cartoony” it will look. In terms of pose, the intention of exaggerate the pose of characters is effective communication. The pose should be strong enough for the audience to get what is happening with the characters by read one image of the characters.
In order to push the pose exaggerate and “cartoony “enough for audience, the rig should be able to perform a kind of broken effects and without any limitation.

Rig design process Part 2 Squash and Stretch

Squash and stretch shows the direction of force and the senses of speed





In the 12 principles, some are important in considering character rigs such as Squash and Stretch. It is the most foundational principle but it was only recently be appreciated in CG world, CG movies such as “Open Season” and Madagascar”, the new squash and stretch treatments of character has become a significant element. Elements can be compressed by itself, expanded and stretch out .the variation of the rigidity makes characters more freshly and achieving a more comedic effect, it also can emphasize scene of speed and weight.

Smear is text of squash and stretch which had been discovered by Check Jones, cartoon director of Warner Brothers, instead of brush stroke, the images of the characters were smeared in the in-between which emphasized of the scene of speed and the fluency of the movement could not be replaced by motion blur.
In item of character rigging, the character should be able to wholly and partly deform, limb, torso and head should be deformed and smeared individually.

Rig design process Part 1 12 Principles

Before jump in and start working on a character rig, we should think ahead and to realize what the exact requirements of the rig in order to achieve the animate production. This will save our time by creating only what is necessary. The main theme of my project is the development of “cartoony” character and animation. Before we started get into the further section, it is necessary to understand and clarify what are “cartoony” motion, emotion, and the interaction with the environments.

When we talk about the “cartoony”, we are talking about the rubber hose characters, the red carpet tongues, bulging eyes; we are talking about the style of animation developed in the twenties at Disney and Warner Brothers.

In order to train young animators, the principles of animation were created in the early 1930s by the animators Walt Disney Studios. These principles became one of the foundations of hand-drawn cartoon character animation, as they are commonly referred to, also helped to transform animation from a novelty into an art form. The best way to determine the requirements of our rigs is get relevant reference such as those principles of animation.

According to the book " Illusion of Life" , the principles of animation are :

1. Squash and stretch
2. Anticipation
3. Staging
4. Straight-ahead action and pose-to-pose
5. Follow-through and overlapping action
6. Slow-in and slow-out
7. Secondary action
8. Timing
9. Arcs
10. Exaggeration
11. Solid drawing
12. Appeal

The original principles are still relevant today because they help us to create more believable characters and situations. These principles originally referred to 2D characters, we must consider how apply those principle into our characters.