3D Character animation principles

Transcription

1 References: (Breakdown poses) on/principles/follow_through.htm (Follow through and overlap) (pose to pose animation) (overlapping) (character walk cycle) (12 basic principles of animation) nsert_joints.htm,topicnumber=d30e (definition of joints, ik handles, rigging etc) 3D Character animation principles Joints: Before animating your fully modelled character in Maya you need to make a skeleton for it to add the controls to. Bones and joints make up the skeleton. Many joints are used in the skeletal positions where the character will twist and bend. Usually, individual joint chains are made for the arm, leg and for the spine and head. The joint chains are the grouped to make a single skeletal hierarchy. IK handles: The joint where the IK handle begins, in the IK chain, is called the start join. Where it ends is called the end joint. Joints amongst the start and end joints are controlled by the IK handle and the solver. The end effector is at the end of the IK handle. When the IK handle is moved the IK solver uses the end effectors location and orientation, to rotate the joints that are in the IK chain. The IK handle tool is the green line attached from one end of the skeleton joint to the other

2 Rigging: Virtual skeletons, or as they are also knows as rigs, allow the animators to move the models body features such as the legs, arms, facial expressions, and posture. This allows them to make lifelike animations. Rigging basically adds bones/skeleton to the whole of the 3D model. The animator creates control points that he can move, bend and deform to make the animations. Once the whole of the skeleton is made and attached to the model, the animator needs to weight the rig. This is when the strength of each joint on the polygons/part of the model changes around the area. Clothes and hair from the character can also have controls to make them move in a realistic way. Binding: By using the bind tool, you can choose to connect (bind) the skeleton to the characters 3D body. By using smooth binding, it creates influence over different areas on the model. Skinning: This involves working with the model for it to be changed later in the skinning process. The skeleton and 3D model needs to be selected as a group to then be binded with each other. Once the model is bound to the skeleton, the joints and the bones are movable; the skeleton and 3D model move together like a humans joints. The three types of skinning are smooth, rigid and indirect.

3 Smooth Skinning: Smooth effects can be created when the joints bend and move. This technique allows many of the joints and other parts of the body that are influenced to have different amount of influences. Rigid Skinning: Stiff and rigid effects can be created. The technique allows only separate joints to have an effect/influence upon the cv s or vertex points on the model itself. Indirect Skinning: Deformers can be wrapped as skin on the skeleton. When this technique is used, the bound deformers change the models skin when the skeleton is manoeuvred and set in different poses. Controls Many controls are made when rigging your character model. This helps to make it easier for the animators to select controls of each of the characters joint when animating. The controls are clear and visible and don t take very long to make. Shapes are created to form the controls for the 3D model. Any movements that the body joints can do on a human body can be performed on a fully rigged model. Left/right foot_control: These are shapes (rectangles) that are created at the bottom of the feet. They control the whole of the feet movement, such as moving it up and down, back and forth, rotating it left to right. Left/righ_knee_PV_Constraint: As in the name, these controls move the knee from left to right. However not up and down, as the human knee does not move up and down if selected separately. If the left is moved up and down, the knee moves with it.

4 Left/right_Clavicle_Control: The clavicle is a bone at the top of the shoulder. As with the model, the shoulders move back and forth, and up and dow n. This also controls the whole of the arm. Left/right_Arm_Control: The arm moves up and down, left to right. The control can also move the rest of the arm. Left/right_Hand_Control: Only the rotation of the hand moves, and nothing else. The hand moves in the same rotation as the arm of the human body. Hip_Control: NURB circles are created and then attached to the body. Control of this allows movement of the waist as a rotation and movement from left to right, and forward and back.

5 Head_Control: This allows the movement of the head. It can move in a rotation with back and front, left to right, up and down. Timing This usually refers to the actions speed in animation. Correct timing in an animation will give off meanings of physical and emotional messages about the movement. Care and time is needed when working on the animation of a character because a suitable amount of time, the build up to the action, and the reaction is important to get right. Viewers can sometimes not notice or recognise the action if it is too quick, and even lose careness if it is too slow. How well the idea is portrayed and read to the audience, is determined by the speed of an action. The weight and look of the character or object being animated needs to be taken into consideration when animating. For example, if the character is heavy, he will take long and greater steps when walking. Whereas, if the character is skinny and light, they walk faster and have more of a brisk walk. To determine the effects of the animations, changing the space or time amongst the frames between poses is important and produces different outcomes. In this example, the ball that is hit and takes 1 second to move is much lighter than the ball which is hit and takes 3 seconds. This makes the viewer understand if the ball is heavy or not.

6 Breakdown Poses Key poses: This is the main pose within an action or movement of the character. For example, if the character getting up from the floor, the first key pose would be the character on the floor. The second key pose is when the character is standing up. Breakdown poses: This is the pose between two keys in the animation process. Elbow bending, timing eases and rotation paths are defined in breakdown poses. In-between poses: These are all the poses used between the key and breakdown poses. The extra drawings used to make the animation smooth are the in-between poses. In this example, the man is falling on his back. To indicate what the keys, breakdowns and in-between poses are, they are marked on this example. Keys: Circled numbers. Breakdowns: underlined number No in-between poses are marked on the example as the animator creates them. The red numbers would need to be shown as they designate the inbetweens that are created. The in-betweens are marked as red. This shows the animator where poses need to be added. Keys and

7 Walk cycle: There are commonly 12 frames per second in a walk cycle, with the 13 th frame being the same as the first one, however on the other side. This then leads up to there being another 12 frames of the walk cycle, to add up to 24, with the 25 being the same frame and position as the first frame. This exact number of frames makes it look like a smooth animation of the character walking. 1 st frame 13 th frame, switched to other side 25 th frame, same as first You can see each step clearly in this example of the animation walk cycle. The character poses are spread out more, so you can clearly see each frame one by one. The keys poses, breakdowns, and in-between poses are labelled in this example. As the character starts to walk, you can see the shift in its momentum with the arms swinging back and forth, and the legs alternating per step.

8 I have created my own animation cycle using my Knight for the flash game. As you can he is striking his sword as if he is hitting something or someone. When he starts to lift his arm up and then bring it down, his knee/leg bends to show he is applying some force/pressure when striking the sword. His head and shoulders starts of at the normal height position, then when the sword comes down, the head and shoulders do too. Follow Through The term refers to when one part leads the action, and another part follows after it.. For example, when a firsbee is thrown, the hand keeps moving, even after the Frisbee has been released. Another example is when an arm is waving; the aaction starts off with the shoulder, then the upper arm, then the forearm, and finally the hands and then fingers. When it comes to motion within the human body, if they are walking, the hip moves first. The leg and then the foot follow after. When the main part of the motion (the hip) stops, the leg and foot continue a little further and eventually come to a halt. When the person throws the Frisbee, the motion of the arm carries on, even when the Frisbee is in the air. 1 to move move: Hip 2 nd to move: Leg/knee 3 rd to move:foot

9 Overlap A second action will start before the first action finishes. As there is no stop time between the actions, there is always something going on, and does not bore the viewers. The overlapping technique is used by animators to highlight characters actions and moods. Character body parts will move before or at different speeds than others. The body parts will also lead the action and even follow the main action itself. The use of overlapping actions is to make the animation flow better. This is usually done with the body, hair and clothing, to follow the lead actions and movements on a character. It is also important to calculate what part of the body makes others move, and at what time within the action being performed.. If this is not done correctly, it will confuse the audience and will make the animation look weird. In this example of the character jumping in the air and then landing, the legs start of the action. It s what starts the process, which is then followed by the spine, head and arm movements, which follows after. The actions (spine, head, and arm) after the legs are the overlapping, as they keep moving, even after the legs stop. This shows an arm moving up and down. When the arm is elevated, even then, secondary actions follow the leading action itself. The shoulder moves first, which is followed by the elbow, then the wrist and finally the finger/tips. Shoulder-1 st Elbow-2 nd Wrist-3 rd Finger/tips-4 th

10 Pose-to-Pose animation Important positions within a characters animation, such as the key poses, describe the vital points in the motion, or the expressions or moods. In pose to pose animation, the animator charts out the action before the actual animation is made, by charting the key poses on the timeline of the computers software/programme. Using pop through allows the characters to enter the scene at a certain place and time. Furthermore, using the technique is helpful when certain tasks, within a certain amount of time, or if actions need to be in line with some music or sound, from the character need to be performed. Before the final animation is rendered, the timeline in which the key poses are mapped out, can be checked and re-visited to make final decisions of how it looks. Other people in the team can be given different parts of the work as it s broken down. Key poses in pop-through animation describe what s happening. In this example, the two key poses in the animation are shows. Both poses illustrate different expressions, in the form of the squad and stretch. Also, the character changes emotions, form happy to sad.

11 12 basic principles of animation Frank Thomas and Ollie Johnston, who were animators working for Walk Disney, came up with 12 basic principles of animation. These important principles been used since then to make the illusion of characters moving in a cartoon, to look as realistic as possible. These 12 basic principles are: 1) Squash and Stretch: This action gives a sense of weight and flexibility to a moving character. It also helps when the animator works on the characters facial expressions and dialogue. Examples of using this technique can be used with a bouncing ball, and when animating a person s body weight. The animation can look somewhat comical, if the character is squashed or stretched to an extreme point. 2) Anticipation: This prepares an audience for an action the character is going to perform. This makes the action come across as being more realistic. For example, if a baseball pitcher throws a ball, the anticipation leading up to the main action, is the pitchers wind up. 3) Staging: The aim is to direct the audience s attention to the characters attitude, mood, reaction or idea as it relays with the story and continuousness of the story line. The presentation of ideas such as the action, personality, mood or expression is what needs to be expressed to the audience. Staging can be completed by using character placement in the frames, camera angles to tell the story such as long, medium, close-up etc, use of light and shadow. One action should be clearly explained to the audience at a time for

12 them to understand the message. Also, the background should not take over the viewers attention when the animation is playing out. 4) Straight ahead and pose to pose action: Straight ahead action is drawing out a scene frame by frame from the beginning to the end. It makes for a better flowing, and lively impression of movement which makes it better if you want to produce realistic action. However proportions, size and volume cannot be exactly the same each frame. For example, fast actions that look wild are made this way. Pose to pose is planned out better, and important drawings are made within parts of the scene to be recorded. This makes it easier to work and have a better size, proportion, and volume. Pose to pose is better used for dramatic or emotional animations, with placement to the surroundings are more important. 5) Follow through and overlapping action: Follow through is when the characters main body stops, other parts will continue to move, but eventually will stop as well. For example, long hair, arms, clothes, a dress. Nothing will stop all at once in a movement. This technique is called follow through. These techniques give the characters more of a realistic action.

13 Overlapping action is when the direction of the character has changed whilst the hair or clothes keep moving in the forward direction. When the character moves in the new direction, a few frames later, his clothes in the new direction also. To make the use of drag and overlapping action look lifelike, timing becomes an important factor. 6) Slow-out and Slow-in: When an action plays out, there are normally more drawings at the beginning of the start of the action, a few in the middle, and more near the end. By using less drawings, it makes the action look faster, and more drawings makes it look slower. The use of this principle makes the action being played, to look more lifelike. An example is a child on a swing, they are slow when they are up in the air on either end, and fast when they are in the middle.

14 7) Arcs: When it comes to character actions, they always have to hollow an arc or circular path shape when moving. This is mostly used when it comes to animation the human figure or animals. This makes the animation look more realistic, and has flows more naturally. For example, when animating a finger pointing, all the drawings showing the animation should have the fingertips following an arc shape from the start of the frame to the end. 8) Secondary action: By including a secondary action to the main action, it gives the scene more life, and enhances the main action itself. An example of this technique is, if an angry character is walking down a road and the walk shows aggression. A secondary action is included that would involve strong motions of the arms working with the angry, forceful walk. By just simply adding in a secondary action, it emphasizes the main action and gives the scene a more lifelike meaning. 9) Timing: The amount of drawings/frames there are for a given action, determines how fast the action is. More drawings between the poses makes for a slower yet smoother action, however less drawings makes for a more faster yet crispier action. Using this principle adds interests to the characters movements. Many animations are made on twos, which is just one drawing photographed on two film frames. They can also be made on ones, which is one drawing photographed on each film frame. The importance of timing is used to create a characters mood, reaction, emotion, and personality.

15 10) Exaggeration: Characters movement should look quite broad, to make them come across as natural in what they are doing. This is the same with facial expressions, however the broadness used in a carton should not be used in feature animations. By using exaggeration, presenting the characters action to look similar to reality, however as its animation, to present it a more extreme way. However using too much exaggeration in animation, can make the scenes and characters come across as being too theatrical and will look overly animated. 11) Solid drawing: This involves drawing characters from angles to make it look believable and to make the characters look alive. What needs to be added in is, form weight, volume solidity and also the illusion of 3D to animation. The drawn animation scenes are made into colour and movement, which gives the characters the impression of 3D and 4D. 3D being the movement in space, and 3d being the movement in time. 12) Appeal: All animated characters, whether they are heroic, villainous, cute and cuddly, funny, should have appeal. Viewers will become more interested in the animation/characters if the appeal of the characters has an easy to read design, has a clear drawing and also a development of personalities. Examples

16 of making a character associate with the audience are; adding a baby-like face for a likable character, or a screwed up face for an evil, non-likeable character.