In the earlier chapters, we learned how to create custom character rigs using bones, bipeds, and CAT tools. We also learned how to bind these rigs created to a character mesh. In this chapter, we look at and understand the various phases of the walk and run cycle and learn how to animate a walk and run cycle for bones, bipeds, and CAT rigs manually.
I use reference videos from Endlessreference.com as backdrops to animate the character in this chapter. You will not see these files in the chapter folder, since they are third-party copyrighted content and I cannot share the videos with you. I recommend their YouTube channel ( https://www.youtube.com/user/endlessreference ) for similar videos and their official website ( https://endlessreference.com/ ), which has more than 500+ reference videos of various actions of humans. This is a must-have reference for anyone who is looking to advance in the field as an animator. To follow along, you can download any of the available content on the Internet or shoot a video as a reference, as seen on the YouTube channel provided here.
In order to animate realistically, we need to understand how our body parts translate over time. In the coming section we will analyze a walk cycle and split it into key phases. The techniques learned here can be applied to character animation as a whole in any 2D or 3D animation program.
Analyzing: Walk Cycle
Walk cycle poses (image courtesy https://endlessreference.com/ )
One Stride/Half a Cycle
The picture shown in Figure 8-1 is of half a cycle. Note that the character starts with its left step first and ends with the right leg in front.
Pose a: This is called the Contact pose. This is where the character has neither of its feet completely planted on the floor, as in Figure 8-1. The character’s left foot is about to rest entirely on the ground and the right foot is about to lift off to transition to the next pose.
Pose b: This position is called the Down pose or weight down pose. In this position, the character’s leg in front will take on the weight of the whole body, as the other leg transitions to the next pose.
Pose c: This is called the Passing pose. From this point the character takes on the whole weight of the body while the other leg comes to the front.
Pose d: This step is called the Up pose or weight up pose. In this position the character’s back leg will take on the weight of the body. At this position, the character will also be at its peak height.
Pose e: This is the Contact pose again and at this stage we are at half a cycle.
- Poses a and e are opposites.
In a, we have the left leg forward and the right leg in the back.
In e, we have the exact opposite of a, wherein the right leg is forward and the left leg is back.
Poses b and d are the same in a way. In b, the character begins to take on the weight of the body so that the other leg can transition. In e, it’s the opposite because it takes on the whole weight on one leg and pushes itself up so that the other leg can transition.
Two Strides/Complete Cycle
Complete walk cycle poses (Image courtesy: https://endlessreference.com/ )
a and i are the same in terms of leg footing, which makes this a loop.
b and f are the same with the exception of alternating footing, wherein e changes our footing for the second stride.
c and g again are the same with alternating footing. Both are a passing pose.
d and h are the same with alternating footing.
I would also like you to keep in mind so far we looked at only the leg footing, now let’s look at the arms motion on a complete walk cycle.
Arm Locomotion
Generally if you notice when you walk, your arms alternate movement based on your legs. For example, if your left foot is in front, the right arm swings forward. If the right foot is in front, the left arm is swinging in front. One important factor to becoming a good animator is to observe and analyze motion around you. When the left leg is in front, the right hand swings forward. The amount and intensity of the swing varies from person to person. We discuss later about creating varying persona, which affect the way one walks, by altering the timing and spacing of keys. Note how the arms come into a neutral position (close to straight down) during passing poses.
Upper Body Locomotion
Observe the line drawn along the hip area of the complete walk cycle. See Figure 8-3.
Pelvic motion: up/down reference (Image courtesy: https://endlessreference.com/ )
The motion of the pelvic area is not limited to this. The pelvis moves to the left when the left foot is forward and moves to the right when the right foot is in front. This motion will create a hip sway motion.
- The pelvic area will also rotate favored by the foot in front. This rotation will be on two axes, the Z and Y. This combination of rotation and translation can make a walk seem masculine or feminine. Refer to Figure 8-4. The axis of rotation is the green and blue, which are Y and Z, respectively.
Figure 8-4Pelvic rotation
Another advantage when animating the pelvic controller is that when you move or rotate the pelvis, the IK chains that we have set on the rig allow for natural human motions. When you bring the pelvic controller down, the knees will start to bend. The leg will straighten up when you move the pelvic controller up in your rig.
The upper chest area also sways a bit to the left and right and inherits an acute translation and rotation from the hips.
Head Locomotion
The head motion for a walk cycle animation is very limited. In most cases, the character is looking head on straight and swaying a few degrees from its neck towards the left and right and a bit of up and down motion. Again, much of this depends on the animation we are creating. For example, if the character is taking a stroll in a park, we would want our character to look around and admire the surroundings.
Enough with the theoretical lessons—let’s go ahead and animate a walk cycle.
Animating: Walk Cycle
Before we begin creating a walk cycle, I would like to let you know that there are two ways in which a walk cycle can be created. One is where the character walks in place (most widely used in games) and the other is known as walk away, where the character moves forward in the 3D world.
Animating the Walk in Place
- 1.
Load 3ds Max.
- 2.
From the command panel on the right, choose the Create tab ➤ Helper section ➤ Dropdown and choose CAT Objects. Click on CAT Parent and choose Base Human.
- 3.
With the base of the CAT rig selected, align it to 0, 0, 0.
- 4.
Let’s set up our timeline to be 60 frames and be running at 30fps so the overall animation will be two seconds. This should be sufficient for to fit a two-stride walk cycle.
- 5.Let’s look at the two-stride walk cycle and space out the keyframes. Refer to Figure 8-5, which shows a two-stride walk cycle. We will be creating the animation using this as reference.
Figure 8-5Complete walk cycle poses (image courtesy: https://endlessreference.com/ )
- 6.We want this walk cycle to fit in a 60-frame animation. So:
Pose a at frame 0
Pose b at frame 7
Pose c at frame 15
Pose d at frame 22
Pose e at frame 30
Pose f at frame38
Pose g at frame 45
Pose h at frame 52
Pose i at frame 60
- 7.
Select any part of the CAT rig and, in the command panel, switch to the Motion tab (Command Panel ➤ Motion).
- 8.
In the motion panel, layer manager rollout, click on the Abs button. From the flyout, choose Create an Abs Layer.
- 9.Select the newly created layer in the layer manager and change its name in the Name section to Walk_Cycle_Feet. See Figure 8-6.
Figure 8-6CAT rig animation layer
- 10.
When you see a red stop button below the layer manager rollout, click on it. It should turn into a green playhead. In this state, you can begin setting keyframes.
- 11.
Once it’s set, turn on AutoKey and begin posing the characters. For the legs, I use the Base HumanLPlatform and Base HumanRPlatform.
A checkpoint file has been created called Walkcycle_Inplace.max. At this point, you can create the arms movement in the same layer, but I suggest you create a new local adjustment layer with the icon [+L] and do the arm swing motion in it.
- 12.Now let’s begin working on the arm swing. Create a local adjustment layer in the layer manager and, with Figure 8-5 as a reference, position the arms accordingly. The person in this reference doesn’t swing her arm much. We can mimic her motion in three keyframes for a rough draft. I will be animating only Base HumanRPalm and Base HumanLPalm for the arm animation.
Pose a at frame 0
Pose e at frame 30
Pose a at frame 60
I am using pose a again at frame 60, because at frame 60, the arm is in a different place and at frame 0, it’s in an entirely different place. In order to loop animation, we want the beginning and end frame to be the same. I have gone ahead and tweaked the hand motion.
A checkpoint file, with the feet and arm animation, is provided for your reference: Walkcycle_Inplace01.max.
- 13.
Now let’s begin animating the character’s hips. Create one more local adjustment layer and rename it Hips_Adjustment.
If you look at the reference image (Figure 8-7), note that I drew a line near the pelvic area. Notice the up and down position of the hips in various poses. Note that the hip is at its peak height at poses d and g.
Figure 8-7Hip motion: up/down reference (image courtesy: https://endlessreference.com/ )
- 14.
Let’s animate the hips. Select the Hip_adjustment layer in the layer manager.
- 15.
Try to mimic the hip motion by moving it up and down a few units. Play back and preview the animation and tweak the keys as needed.
- 16.
Add one more local adjustment layer and name it Hip_Sway. In this layer, animate the sway of the hips based on the footing. I recommend that you analyze body postures as you walk.
A checkpoint file has been created for reference: Walkcycle_Inplace02.max
- 17.
Let’s add one more local adjustment layer and name it UpperBody.
- 18.
In this adjustment layer, we are going to animate the base HumanHead movements and base HumanRibcage movements.
In the reference image (Figure 8-7), the person walking is looking straight at the camera so there is very little to no movement.
- 19.
I have tilted the head and rib cage up and down and sideways a bit, based on the footing of the character. Play back and preview the animation.
A checkpoint file is saved as Walkcycle_Inplace03.max. We have completed one walk cycle. Now we’ll see how the character walks multiple steps.
I exaggerated the head animation a lot. If we had created an animation adjustment layer for head movement, we would be able to delete that alone and recreate it.
Animating the Walk Away
- 1.
Load 3ds Max.
- 2.
From the command panel on the right, choose the Create tab ➤ Helper section ➤ Dropdown and then choose CAT Objects. Click on CAT Parent and choose Base Human.
- 3.
With the base of the CAT rig selected, align it to 0, 0, 0.
- 4.
The frame rates are the same as earlier. Let’s make our timeline 60 frames and the playback speed set to 30 frames per second in the Time Configuration window.
- 5.We will be spacing the keyframe the same as for the walk in-place, but we will be posing the character for all the body parts (see Figure 8-8):
Pose a at frame 0
Pose b at frame 7
Pose c at frame 15
Pose d at frame 22
Pose e at frame 30
Pose f at frame38
Pose g at frame 45
Pose h at frame 52
Pose i at frame 60
Figure 8-8Complete walk cycle poses (image courtesy: https://endlessreference.com/ )
- 6.
With any part of the CAT rig selected, go into the motion panel and, in the layer manager, create an absolute layer. Name it Walk_Away_Cycle. This is the only layer we are going to use.
- 7.
Ensure that the setup animation is turned on in the layer manager of the CAT rig motion.
- 8.
Turn on Set Key.
- 9.
Set pose a at frame 0. Tweak the legs, arms, head, and any other parts at this frame.
- 10.
Move to frame 7 and animate the parts. This time I want you to select the hips and move forward. Move the forward leg until it is no longer bending at the knee. Notice how the other parts of the body compensate.
- 11.
Make any manual changes in frame 7, such as the leg rotations.
- 12.
Let’s move ahead to frame 15. Select the hip and move it forward until the leg that is forward is perpendicular to the ground. Now make adjustments to the other feet and arms.
- 13.
Keep progressing with poses over time, as indicated in Step 5. The only thing you need to do is move the hip position forward.
A checkpoint file has been created called WalkCycle_WalkAway01.max. Note that I animated only the hips forward motion and the legs. If you play back the animation, the character will be moving forward in 3D space.
Animating: Walk Cycle Loop
- 1.
Load Walkcycle_Inplace03.max.
- 2.
Open the time configuration and set the end frame to 600. The Time Configuration dialog can be accessed by clicking on the stopwatch icon below the play controls. Once the end frame is set to 600 frames, play the animation to see how the character walks for 60 frames.
- 3.
Open the mini Curve Editor and select Base Human from the viewport.
- 4.In the Curve Editor, expand the rollouts until you can see layers, as shown in Figure 8-9.
Figure 8-9Mini Curve Editor
- 5.Note that these are the animation layers we created. Now select all the layer names that we animated. You can select the first name and hold Shift and then click on the last one to select all the animation layers. See Figure 8-10.
Figure 8-10Mini Curve Editor: all animation layers selected
- 6.Once all the animation layers are selected, in the mini Curve Editor, choose Edit ➤ Controller ➤ Out of Range Types. See Figure 8-11.
Figure 8-11Mini Curve Editor: Out of Range Types option
- 7.Once you click on the Out of Range Types option, you will be presented with a dialog box, as shown in Figure 8-12.
Figure 8-12The Out of Range Types dialog box
- 8.
Click on the Loop thumbnail. Note that the in and out points turn blue, which indicates that the current selection is loop.
- 9.
Click OK and then wait. It might take a moment for the software to apply the loop. Do not panic; the software is not frozen.
- 10.
Once the dialog box vanishes, play and preview the animation. Voila, you have created a looping animation!
A checkpoint file has been created called Walkcycle_InplaceLoop.max.
This technique can be applied to any animation that has beginning and ending keyframes with the same values for position, rotation, and scale. Unfortunately, this cannot be applied to the Walk Away cycle because the position of the rig parts are at different coordinates in the first and last frame of the animation.
You can still attempt to loop it, but the results will be very erratic and undesired.
Analyzing the Run Cycle
Contact pose a: This is the key pose where we begin and end with the same pose for a loopable run cycle, as seen in the walk cycle.
Pass through pose b: The running pose. This is similar to our pass pose in walking. This is where the legs change lead to front.
Up pose 1/Kick off pose c: This is where the character begins to gain momentum to lift up.
Up pose 2/Air pose d: This is where the character gets air time. In this pose the character has both its legs up in the air.
Contact pose e: This is the same as the contact pose, but with alternating legs.
Run cycle poses, half a cycle
Rotomation
Another technique used by animators to animate lifelike motion is called rotomation. Rotomation is like tracing artwork on paper. We sketch frames over time and create an animation. Let’s dive into an example of how to set one up. Again for this purpose we need a video reference. As I mentioned earlier, I recommend the YouTube channel ( https://www.youtube.com/user/endlessreference ) for reference videos. Their official website ( https://endlessreference.com/ ) is good for high-quality videos of varied animations. The kind of video required is something similar to https://www.youtube.com/watch?v=G8Veye-N0A4 . The grid overlays are optional but helpful.
- 1.
Fire up 3ds Max.
- 2.
In the left or right viewport, create a box. The dimension of the box should match the video dimensions. For example, the dimension of the video I used is 1280x720. I do not want to create a box that is 1280 units big, so instead I can simplify it by dividing it by 100. So my box will be 12.80x7.20.
- 3.
Once the box is created, press M to create a material. In the Material Editor, click on an empty slot (any unused material slot is an empty slot). In the Diffuse parameter, click the button next to it.
- 4.Click on the small button next to Diffuse, as shown in Figure 8-14.
Figure 8-14Material Editor
- 5.Click on the Bitmap option from the box that pops up and click OK. Refer to Figure 8-15.
Figure 8-15Map Browser
- 6.In the Open dialog box, browse to the location you have saved your image sequence and choose the first image. Ensure that the image sequence checkbox is checked, as shown in Figure 8-16.
Figure 8-16Select Bitmap Image dialog
- 7.
Once you have done this, click the Open button.
- 8.You will be presented with one additional dialog box; click OK to accept the settings. Note the end frame number from the file list control, as you need that number to set the duration of the timeline (see Figure 8-17).
Figure 8-17File list control
- 9.Select the material and drag and drop it on the box you created. Toggle the Show Shaded Material in Viewport option. See Figure 8-18.
Figure 8-18Material Editor, show shaded material in viewport
- 10.
You should now be able to see the image in the box. Open the time configuration and set the end time as specified in the end frame that we saw earlier in the Image File List control.
- 11.Your 3ds Max viewport should look something like Figure 8-19. We are going to use this as a reference and animate our character rigs.
Figure 8-193ds Max UI: image sequence on box (Image sequence courtesy: https://endlessreference.com/ )
- 12.The next step is to bring in your rig or create one. I am going to create a CAT rig. Position your box behind the CAT rig, as shown in Figure 8-20. Reposition and scale as applicable (when scaling, use the uniform scale option).
Figure 8-203ds Max UI box lined up to the CAT rig (image sequence courtesy: https://endlessreference.com/ )
- 13.
Right-click the box and, in the object properties, uncheck Show Frozen in Gray. Then freeze the box. This way you don’t accidentally move the box.
- 14.
Now you can start key framing the rig over time based on the backdrop shown in the box. Follow the steps in the Animation Walk Cycle section.
This is rotomation explained in a very basic way. A lot of animators use this technique to create quality animations.
Quadruped Run/Walk Cycles
Walk
Amble
Pace
Trot
Canter
Run or gallop
It would be really hard to explain the footing of a quadruped in words. I refer you to an Internet source, where they simulate a quadruped and provide you with a binary file to preview the walk/run styles for a dog. (I take no claim on this link and copyrights remain with the respective author. This is being provided as a reference for you to practice and understand better: https://www.cs.ubc.ca/~van/papers/2011-TOG-quadruped/index.html .)
I recommend you study the pattern of a dog’s leg movements as it speeds up. A rotomation technique would be a good starting point when animating quadrupeds. As you begin setting keyframes, it would be easier to grasp the patterns in the leg’s locomotion.
- 1.
Load 3ds Max.
- 2.
From the Create panel, choose Helpers ➤ CAT Parent. Create a Panther CAT rig from the preset. We are going to use this rig, as it can be used for a wide range of animals (cats, dogs, wolves, lions, tigers, etc.). A reference file has been created called Panther_CATRig_Start.max.
- 3.
Once the CAT_Rig is created, select the base triangle of the rig and go to the motion pane of the command panel.
- 4.Create a CAT motion layer from the layer list, as shown in Figure 8-21.
Figure 8-213ds Max CAT motion layer, CAT rig
- 5.
Once a layer is created, click on the Setup/Animation toggle. The red Stop button is below the layer manager, as depicted in Figure 8-22. When you click it, it should become a green play icon. The panther rig will change its posture as well.
- 6.
Press Play and you should see the rig walking in place. A checkpoint file has been created in the scenes folder called Panther_CATRig_Start01.max.
- 7.This is a default walk. We can tweak its speed and alter it to mimic, walk, run, and gallop using the CAT motion editor. Click on the Paw icon, as shown in Figure 8-22.
Figure 8-223ds Max CAT motion editor icon
- 8.Clicking on the denoted icon will load the CAT motion editor, as shown in Figure 8-23. Select the Globals section on the left pane.
Figure 8-233ds Max CAT motion editor
- 9.Let’s look at a few parameters in the Globals section that will help alter the walk cycle a lot. Note that you can play the animation using the play controls and tweak the values to see changes happen in real-time.
Max step time is currently set to 25. If you play the animation, you should notice that the character does a four-step walk. Our total frames are 100. With a value of 25, it’s four steps. Now change the value to 10. The rig begins to walk faster.
Now let’s set the max step time to 75. Play the animation and notice how slow the step is. Also notice how the animation is not looping correctly because the step time is set to 75 and our overall frame is 100. The animation restarts after a second step is initiated but is not completed, as there are only 25 more frames are left. A quick tip here would be to always have the total number of frames of your animation equally divisible by the max step. Feel free to open the Time Configuration window the play ahead and adjust the end frame to 150.
The walk on spot is going to have the rig walk in place. Walk on line is the same as walk away, as discussed in the walk cycle of bipeds.
- 10.
Now let’s switch to the Limb Phases category in the CAT motion editor.
- 11.If you notice in Figure 8-24, 3ds Max names the legs in a weird way. There is no label for the front and back legs. Legs 1 and 2 are for the back, and legs 3 and 4 are the front legs.
Figure 8-243ds Max CAT motion editor, limb phases
- 12.Set the leg values as follows:
1LLeg to 0.25
2Rleg to 0.25
3LLeg to -0.25
4RLeg to -0.25
- 13.At this point, I would like to show you one more option. Let’s reset the leg values to their defaults:
1LLeg to -0.25
2Rleg to 0.25
3LLeg to 0.25
4RLeg to -0.25
Change the Max Step time to 75 so that the rig walks very slowly.
- 14.
Now turn off Setup/Animation mode by clicking on the Green play icon in the layer manager. Your rig will go into the default pose. At this point if you play and preview, there will be no animations.
- 15.Select the PantherRibcage and PantherPelvis and bring them down until you see the rig get into a posture of a predator sneaking up on its prey. Move and rotate the head as needed. Refer to Figure 8-25.
Figure 8-253ds Max CAT motion editor, sneak posture
- 16.
Now select the base of the rig, the triangle, and go into motion options. Turn on setup/animation mode and preview the animation. Now you should see the predator sneaking. Notice how, by adjusting the base position, we were able to get a varied motion. Tweak it and test multiple values to get varied results. A reference file called Panther_CATRig_Start02.max is provided in the scenes folder of Chapter 8.
Note that we didn’t touch the tail in this exercise. It is like a stiff stick. You can animate it by giving it twist and rolls, as well as add sway to the heads, shoulder twists, and much more. You know the tools now, so go ahead and bring the object to life.
Summary
In this chapter, we learned the key poses of walk and run cycles for a biped, as well as about a technique called rotomation that is widely used by animators. We used the CAT rigs motion tool to create procedural animation and tweaked its parameters to get walk, run, gallop, and Sneak animation by just making a few adjustments. Remember that these are still rough animations. They need a lot of refinement and tweaking before the object can be called a finished one. Look and analyze multiple references and see what the character is missing. In the next chapter, we cover facial animation using morphs and facial rigs.