Animation Case Study: How I effectively Apply Principle Of Animation To Create A Realistic Walk Cycle 3D Animation In 3 Hours

Bean Sprout F3R3 MethodIn this post, I'm going to walk you through how I create a realistic walk cycle 3D animation by applying the principles of animation in the most effective way.

I have been using this method when I started learning animation to create my walk cycle animation in Maya. Until now, I am able to apply this technique in my walk cycle and any other character animation even when I use other software such as Cinema 4D or 3DS Max.

And in this case study, I'm going to show you exactly how I break down walk cycle animation using this method, step by step.

Read on to learn how...

 

The Bean Sprout F3R3 Method: (An effective 3d walk cycle animation sequence for beginners)

 

This is the walk cycle animation I created from scratch in Maya within 2 hours. I used Norman Rig for this walk cycle which is easy and free for beginners to practice.

What I love about this approach is that beginners would not feel intimidated by what is needed to complete a 3d walk cycle. Walk cycle can be done segment by segment and building on top of what is been done previously.

Walk Cycle Left ViewWalk Cycle Front ViewWalk Cycle Perspective ViewWalk Cycle Right ViewWalk Cycle Back View

 

tommy walk cycle 1 front view

Tommy's First Walk Cycle Front View

tommy walk cycle 1 perspective

Tommy's First Walk Cycle Perspective

My student, Tommy, used this method while creating his first 3d walk cycle and this is what he had achieved.

On top of the method, added some fun personalities to his walk cycle by exaggerating the shoulders and arms.

 

 

 

 

 

 

tommy walk cycle 2 side view

Tommy's Second Walk Cycle Side View

tommy walk cycle 2 perspective

Tommy's Second Walk Cycle Perspective View

Subsequently, Tommy, modelled his own 3D character and created another walk cycle animation using the similar method and this is how it looks like.

This round, Tommy made his character looks cool by slowing down his walk cycle animation timing.

 

 

 

 

 

 

 

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Bean Sprout Method

bead sprout methodAnimating a character is similar to how a bean grows. We start with the bean and we see it grows its root, followed by the stem and leaves. Character animation begins animating from the pelvis, followed by the legs, then the upper torso and finally the head and arms. Hence we animate in the following 5 sequence:

A. Pelvis
B. Legs
C. Upper Torso
D. Head
E. Arms

 

The main reason for this breakdown sequence is because bulk of humans weight is on the pelvis. When pelvis is animated correctly, the remaining body parts will follow through nicely. Pelvis is the centre of gravity and thus, balancing motion greatly depends on the position of pelvis.

 

The F3R3 Sequence Method

F3R3 Sequence MethodGrowing a bean needs good foundation such as soil and constant watering and sunlight. Thus we apply simplified version of principle of animation using the Foundation 3 and the Refinement 3 sequence (F3R3 Sequence).

F3 sequence is PoseTimeEase:

  1. Pose the main keyframes in walk cycle
  2. Time and space the key frames
  3. Add in forces by Ease in and out

R3 sequence is OverExagApp:

  1. Add Overlapping action if applicable
  2. Exaggerate when actions aint obvious
  3. Correct any action to look Appealing

Note: The other 6 principles of animation are not included in this walk cycle, which I'll talk about it later in this post.

Now with Bean Sprout F3R3 Method in mind, let's jump straight into the walk cycle animation in 3D.

 

 

Walk Cycle: PelvisA. Pelvis

Richard Williams walk cycle reference

Richard Williams Animator's Survival Kit walk cycle reference

Start by animating the key poses for pelvis with the walk cycle reference from Richard William. This reference is half of the 8 frame basic walk cycle animation. Here is where we apply animation principle, pose to pose. Key poses are mainly poses that start, end or change a motion.

With reference from Richard William's Animator's Survival Kit, a walk cycle consist of 4 main key poses. The key poses are contact, down, passing, up and finally back to contact. We start with contact pose because this pose is easier to define the moment that the character starts walking. We will only be animating the Y axis of the pelvis since this walking cycle will be walking on the spot exercise.

 

 

A1. Pelvis's Contact Pose

pelvis contact down passing up poseAt contact pose, the pelvis is slightly lower than its default standing position. This is the pose where the feet are at furthest distance from each other. We can use the knee angle as a gauge for this pose. The knees should be bend at approximately 15-20 degree when the pelvis is at contact pose. I am not expecting anyone to measure the angle, as long as it is slight bend, it should be good enough.

 

A1. Pelvis's Down Pose

At down pose, the pelvis will go even lower than the pelvis at contact pose. This is the pose when the pelvis is at the lowest point of the entire walk cycle. At this moment, the legs are meant to catch the pelvis weight. Thus, the knees are bend at about 70-80 degree to dampen the dropping weight of the pelvis.

 

A1. Pelvis's Passing Pose

Passing pose is when the pelvis recovers to its default height, that is when the character is standing straight. Passing pose is also refers to one of the leg passing by the other while stepping forward, thus the name passing.

Tip: In 3D, even if the character is standing straight, the pelvis is lowered slightly to allow the legs to be negligibly bend. This is able to overcome a common 'knee popping' issue while animating legs. The height to lower the pelvis will be at the point when the legs just started to bend.

 

A1. Pelvis's Up Pose

At up pose, the pelvis is being pushed up and forward. Walk cycle is a continuous natural motion of a humanoid trying to make himself fall forward by putting himself off balance. Although in real life we are moving forward, for this walk cycle on the spot we only lift the pelvis along the Y axis. The pelvis is lifted to the point where the legs is seen as tiptoeing. The pelvis can pull as high as when the toe is almost lifting off the ground.

 

A1. Pelvis's Pose Completed

Complete the 1 step walk cycle by copying the first key frame and paste it after the fourth key frame. Once the pelvis is animated, it will be moving up and down on its own. There is no timing specified so the movement could be abrupt or slow. Nonetheless, we have gotten the keyframe that we need, we can now move on to the timing and spacing.

 

 

A2. Pelvis's Timing and Spacing

 

pelvis timing and spacing

 

We next apply timing and spacing to our pelvis by giving some inbetween frames between each keyframe we did previously. Inbetweens are frames between key poses. In 3D context, these frames are generated by the software to expedite our animation process. We can add and reduce the number of inbetweens by selecting a key pose and shifting it forward or back.

As this is a basic walk cycle, we will aim to walk the character with a normal speed of 1.5 seconds to take 2 steps. Drag the keyframes away from the previous keyframe, leaving 4 empty frames between each key poses. This will give us a 2 step walk cycle oscillation at about 1.5 seconds, based on 25 frames per second(fps).

FPS settings can be set in Maya by clicking on:

  • Animation Preference
  • Settings
  • Working Unit -> Time: Pal (25 fps)

Autodesk Maya FPS settings

 

Feel free to adjust the inbetweens at this junction to increase or decrease your walking speed to your liking. However, be sure to have consistent inbetweens among these 5 key frames. For example, if there are 7 empty frames between contact pose and down pose, there should be 7 empty frames between down pose and passing pose as well.

 

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A2. Pelvis's Timing and Spacing Completed

Once this timing is set, we will not change it anymore. Changing this timing at a later stage will create lots of amendments in other areas as well. We now move on to the easing in and out.

 

 

A3. Pelvis's Ease in and out

We create a sense of force for our pelvis by applying easing in and out. The contact pose is when our pelvis is dropping due to gravity. However, our legs will slow down the pelvis dropping speed, thus resulting in easing in (deceleration). Easing in and out is created using graph editor. A steep graph will indicate a fast speed while a gentle graph will indicate a slow speed.

When graph changes from steep to gentle, the speed is dropping from fast to slow and this means deceleration.

Pelvis Ease In and Out Graph Editor

Once the dropping motion of pelvis is stopped by the leg, the leg will start to push the pelvis up gradually, thus easing out (acceleration). When the graph changes from a gentle to steep, it means the speed is picking up from slow to fast, thus acceleration.

As the pelvis is being pushed up, gravity pulls it down gradually. This results in an easing in motion, changing the pelvis speed from fast to slow. The graph for deceleration will changes from steep to gentle slope.

Eventually the pelvis drops down due to gravity pulling. Since the pelvis needs to come to a stop, the speed will pick up again from slow to fast. In the graph, the slope is changing from a gentle slope to a steep slope.

 

A3. Pelvis's Easing In and Out Completed

At this stage, we have build a solid foundation for our walk cycle. This is crucial because the remaining animation will rely very much on the movement and timing of the pelvis. Other principles are not applicable for pelvis except for appeal, which I'll cover at the later stage. We will proceed on to the legs animation.

 

Walk Cycle: LegsB. Legs

Begin the legs animation by posing them at the four key poses based on our reference. In 3D legs are controlled by inverse kinematics (IK). That means when we move the feet around, the connecting components of thigh and calf will follow accordingly.

 

B2. Legs' timing

Legs are posed at the respective timing of our pelvis key poses. Effectively, we will be applying two principles in one shot.


 

 

Walk Cycle Done

Once the arms animation is done, the entire walk cycle is complete! Take a few moments to review your walk cycle. Although this might be your first walk cycle, it might look much better than many other beginners. Moving forward, you can consider refining other minor details such as looping, jerky movements, etc.

 

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FAQ

Can I animate both pelvis and legs together? Or Upper torso, head and arms together? Or even entire character at the same time?

 

For beginners, my recommendation is 5 components sequentially as mentioned in this post. Animators who are familiar with the sequence, feel free to animate lower torso (pelvis and legs) followed by upper torso, head and arms. For veteran animators, this could speed up their creation. For expert animators, I hope I'm not leaking too much information for beginners to learn! Animating entire character at the same time is possible when an expert animator has planned well ahead in their mind even before animating. In any case, sequence of the animation principle still applies with slight variation.

 

Why are the other 6 principle of animation sequences left out?

They are left out because for this walk cycle 3d animation, they are not as applicable. The principles of animation that were left out are:

Anticipation (and recovery for acting):
This refers to a preparation action before the actual execution of the motion. This motion could also refers to the recovery action after executing an action. For example, before we toss a bowling ball, we need to swing our arms to the back before we bowl. This is the anticipation action. For this walk cycle animation case study, such action is not necessary because this is a looping animation and there is no start or stop action.

 

Squash and Stretch (situational):
This is referring to a more cartoony visual where a character's legs or arms are stretched comically just like Disney's cartoon. Squash and stretch could also refers to an elastic material such as basketball while doing a bouncing animation. This principle is definitely not applicable in this walk cycle scenario.

 

Secondary actions (Acting and personality):
This refers to a habitual action that a person does unconsciously. A good example is when a person is thinking and he starts to scratch his head.

 

Staging (camera works) :
This refers to the subject on the screen if it is telling the story vividly. In this walk cycle, we only need to make sure the entire character is seen throughout the animation.

 

Especially in 3D walk cycle animation, the following principles of animation are not applicable:

Solid drawing:
This refers to the appearance of the character we are animating. As a 3D animator, most of the time we are not involved in the modeling. That's because animator's are too busy animating to do any other things! To put it nicely, we animators specialize in animating only. 😉

 

Arc motion:
This refers to trajectory or path of motion of a circular motion. For example, when our arms swing, our hand moves in an arc motion because of the pivot point of our arms. In 3D, a character's arm is mostly fixed and cannot be stretched unless it is rigged intentionally. So we do not really need to worry about arc motion in character animation.

 

I've also created a video tutorial on starting a walk cycle animation in Maya. In this post, I share more on the technical aspect of Maya and the character rig.

 

Use the comment box below and tell me what your think!

 

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