WEEK2 : Ball and Tail | Walk Cycle

Part 1 — Ball and Tail

1 . Animation Principles in Ball and Tail

  • squash and stretch
  • timing
  • arcs
  • overlapping and follow-through action
  • anticipation

2. Details of Overlapping and Follow-through Action

Follow-through and overlapping action are two techniques that help make the action richer and fuller with detail and subtlety. Follow-through action consists of the reactions of the character after an action, and it usually lets audiences know how he or she feels about what has just happened or is about to happen.In overlapping action multiple motions influence, blend, and overlap the position of the character. In three-dimensional computer animation a lot of the common follow-through motions of clothing and hair, for example, can be animated with dynamics simulations. The layers and channels in three-dimensional computer animation software allow us to mix and blend different overlapping motions from different areas of the character.

3. Animation Process

References

The movement of the ball with tail also follows the overlap, so I looked for a reference picture of the tail of a squirrel, and the decomposition diagram of the up and down swing and jump.

Key Poses

For a soft and tough object, the main force at a point, depending on its own or external active force, makes the force from one end to the other, and the motion line and shape generated by it are S-shaped curve motion. The trajectory of the S-shaped curve motion of the object is in the S-shape range.

In this model, the tail is bound by three segments and four controllers, and the tail is bent in different degrees by rotation.

The motion trail of the tail swinging up and down when the ball is still.

The motion trail of a ball tail as it jumps.

I think the most difficult part is to control the softness of the tail and the rhythm of the tail swing, which is also the part that I spend the most time adjusting. Because a tail has four controllers, it needs to be adjusted separately to produce a flexible feeling, but if the key frames are too dense, it will be stuck. But if you adjust the key frame too little, the tail is not soft enough and the power is not smooth enough.

Summary

To follow and overlap is to dismantle all parts of an object, and the parts that do not move are driven by the parts that move actively. In this process, there is a time difference in the sequence of actions. Take human hair as an example. In the following movement, the movement of hair is slightly delayed than the head movement, and the hair is still moving when the head is buffered and stopped. In the case of the tail, where the object stops, the tail may still be swinging, and the end of the tail follows more slowly than the part attached to the body. The following degree varies according to the softness of the object, but in order to maintain the softness of the object and the smoothness of the motion, it is necessary to adjust it carefully to ensure the smoothness of the curve.

Link to finished animation

Part 2 — Walk Cycle

1 . Previs & Blocking & Layout

Previs

Previz is the abbreviation of previsualization, which is called visual preview. Some people also call Previz “dynamic split mirror” and “3D storyboard”. To put it bluntly, Previz is actually a simple production of the shooting content before the official shooting, with simple animation to show the actor’s moving position, view, camera angle, camera movement and other major directions, for the director, camera guidance and other shooting reference. In the past, filmmakers used to help them plan their visual presentation by framing, concept maps, solid models, and props. Now this process can be done through Previz.

Usually, the preview is to simplify the production standard of each link of the traditional three-dimensional process, using low-precision model, rough character movement, more accurate camera scheduling, simple lighting, special effects, more accurate editing, to make the film once more, focusing on the production of those shots and scenes with great difficulty and high shooting cost, so as to provide more accurate production data and shooting.

After previs is produced, it is actually the first time to show the comprehensive performance of each link. Each link will be improved on the basis of previs at this stage until it is clear (according to the cycle). According to the different production requirements, the emphasis is also different, according to the different stages of production, the degree of detail is also different.

Blocking

Blocking is an important step for animators to schedule scene layout, design action posture and add key frames on the basis of layout. Blocking is not equal to rough animation, nor is it a simple pose. Before blocking, a lot of preparatory work should be done. In order to design the dynamic of the role and story, especially before depicting specific actions, we must look for reference pictures and videos. Be sure to test bone binding before blocking.

First of all, we can start with some basic attributes, such as rotation and distortion, zooming in and zooming out. But if the character cannot be scaled, it is necessary to scale the environment to adapt to it. Secondly, check the controller of each limb, such as whether the arm can switch between FK and IK freely, whether the ankle joint can rotate 360 ° and whether the toes can open and close together. In short, blocking means that every idea can convey to the audience most clearly and quickly.

Layout

In 3D animation, the responsibility of layout is to determine the role scheduling and camera movement. The character’s own animation is made or not according to the project requirements. The lighting and special effects depend on whether the plot is promoted and the lens needs to be produced (according to the project requirements). In terms of animation, due to the particularity of its production, rough is used The layout stage may focus on the requirements of the character’s action design, animation rhythm and camera movement accuracy, while for lighting, the requirements for special effects are reduced accordingly.

2 . Animation Principles in Walk Cycle

  • solid posing
  • timing
  • arcs
  • slow-in & slow-down
  • pose-to-pose

3. Animation Process

References

A good walking reference map should have three principles: the time axis of frame number, the ground of horizontal line as height reference, and detailed action decomposition.

In addition, I also found some decomposition diagrams of different forms of walking to study the similarities and differences of walking in different situations and personalities. Although animation has not yet done this step, it is helpful to understand walking.

Key Pose with timing

step 1 first contact pose —- frame 1 & 25

In this step, I made the translate y axis the value of -0.134, z axis the value of -0.172 and x, y, z axis rotation values of -6, 11 and -5, respectively. On the one hand, when walking, the whole body will be driven to rotate and twist, on the other hand, in order to see the posture of the left and right feet more clearly.

The foot roll and foot break of the left leg are both value 54.8, and the foot roll of the right one is value -35.9 and with no foot break. (to make the contact pose)

step 2 second contact pose —- frame 13

In order to get a pose symmetrical to the first frame and the last frame, that is, you only need to put negative numbers on the y-axis and z-axis values of the rotation to get a rotation in the opposite direction (the walking direction is the x-axis, so the value does not need to be adjusted to a negative number).

Click the control machine of the left foot to copy the key frame, and then click the controller of the right foot to paste, so as to achieve the action completely opposite to the first frame.

step 3 first passing pose —- frame 7

The foot roll and foot break of the right leg are both value 0, and the foot roll of the left one is value 90 and with no foot break. (to make the passing pose)

Pull up the translate y of the ball a little bit.

step 4 second passing pose —- frame 19

Copy and paste the value from frame 7 onto frame 19, but onto the opposite foot. Copy the y-axis height from frame 7 to frame 19 as well.

step 5 first down pose —- frame 4

In order to keep the right foot close to the ground, change the foot roll of the right foot to value 0, the foot break of the left foot to value 0 to strength the foot out and place it back on the ground with translate y of value 0.

Pull the y-axis down a little bit.

step 6 second down pose —- frame 16

Mirror the down pose from frame 4 to frame 16.

step 7 first up pose —- frame 10

The left foot is raised in the air, and the right foot stands on tiptoe more.

step 8 second up pose —- frame 22

Mirror the up pose from frame 10 to frame 22.

Block

Completed walking cycle.

But after I added the displacement, I found that it was sliding. So I checked some information and said that if I wanted to match the distance between the displacement and the stride, I had to adjust the key frames of the head and tail, and then I adjusted a few frames of the sole landing to ensure that the 12 frames of dropping the toe and lifting the heel remained in the same position, so that there would be no slippage.

A polished walk cycle.

Summary

A walk cycle animation is 24 frames. When I adjust the forward animation, I need to be patient and careful to prevent slippage. Now walking is more common, if added to personality, the range of action is bigger, it will be more interesting. Now the action is still a little stiff, and the bone pause is more obvious, I hope it can be modified better later.

And after I received the feedback of ” The only thing is to feel the step on to the stone more with an extra small bounce in the hips in the graph editor”, I polished and revised it.

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