Character Animation Starter Kit: Building a Walk Cycle with Contacts, Passing, and Extremes

What makes a walk cycle feel believable

A walk cycle reads as believable when the feet clearly “own” the ground and the body’s weight transfers from one leg to the other without pops, slides, or floaty moments. In practice, you’re managing two systems at once: (1) footfalls (where and when each foot plants, rolls, and lifts) and (2) weight transfer (how the pelvis, torso, and head travel over the supporting leg). This chapter focuses on building the classic four-pose walk (contact, down, passing, up), mirroring it cleanly, and polishing it so the center of mass travels smoothly while the feet stay locked when planted.

1) Define walk parameters: speed, stride length, attitude

Choose a simple starting template

Before posing, decide three parameters. Write them down so you don’t “animate by guessing” mid-way.

• Speed (cadence): how many frames per step. A common starting point is 12 frames per step at 24 fps (so 24 frames per full cycle: left step + right step). Slower walks might be 14–18 frames per step; faster walks 8–10.
• Stride length: distance between the feet at contact. Longer stride increases vertical bounce and hip travel; shorter stride feels cautious or tired.
• Attitude: the “flavor” of the walk (confident, sneaky, heavy, relaxed). Attitude mainly shows up in torso lean, arm swing size, and how sharply the foot rolls off the ground.

Set measurable targets

Pick concrete numbers you can check later:

• Step length: e.g., 1.0–1.5 foot lengths from heel-to-heel at contact (varies by style).
• Hip travel: how far the root/pelvis moves forward per step (should match the planted foot distance to avoid sliding).
• Vertical range: small for relaxed walks, larger for bouncy/cartoon walks.

If you’re working in 3D, decide whether the character is walking “in place” (root stays near origin) or “moving forward” (root translates). For learning and clean foot locking, many animators start in place and then convert to forward motion.

2) Build the four main poses and mirror for the opposite leg

Frame plan (example at 24 fps)

This is a practical spacing for a 12-frames-per-step walk. If your step is 14 frames, keep the same order but spread the frames proportionally.

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Pose 1: Contact (heel strike + trailing toe)

Goal: clearly show the moment the leading heel hits while the trailing foot is about to leave.

• Front foot: heel down, toe up slightly (dorsiflexed). Place it exactly where you want the step to land.
• Back foot: toe still on the ground, heel lifted. This foot is about to push off.
• Pelvis: slightly forward between the feet (not centered perfectly). Keep it believable for your character’s build.
• Arms: opposite arm forward to the leading leg (counter-swing).

Pose 2: Down (weight acceptance)

Goal: show the body settling onto the front leg as it takes the weight.

• Pelvis drops to the lowest point of the step (your “down” position).
• Front knee bends to absorb weight; front foot becomes flatter (more of the sole contacting).
• Back foot begins to release: toe still contacts but is lighter; heel remains up.

Common fix: if the down pose looks like a squat, reduce knee bend and reduce pelvis drop. The down is subtle in realistic walks.

Pose 3: Passing (swing leg passes under)

Goal: communicate clean transfer: one leg supports, the other swings through.

• Support leg: straightening compared to down (not locked rigid unless stylized).
• Swing leg: foot passes near the support ankle; toe typically points slightly up to avoid “scuffing.”
• Pelvis: horizontally closest to being over the support foot (this is where balance reads strongest).

Pose 4: Up (push-off + rise)

Goal: show the push from the back foot and the body rising to prepare the next contact.

• Support foot (the one that will become the trailing foot): heel lifts as the character rolls onto the ball of the foot.
• Pelvis reaches the highest point of the step (your “up” position).
• Swing leg extends forward, preparing for heel contact.

Mirror to create the opposite step

Once frames 1–10 are solid, create the opposite contact at frame 13 by mirroring the pose (left/right swap). Then repeat the down, passing, and up for the opposite leg. Practical tips:

• Mirror poses, not curves. After mirroring, check that planted feet still align to the ground plane and that toe angles didn’t flip oddly.
• Keep the character’s forward direction consistent; ensure mirrored poses don’t introduce unintended twists.
• If your rig has a “mirror pose” tool, use it; otherwise manually swap rotations and positions for symmetrical controls.

3) Clean foot roll and toe-off (no advanced rig features required)

Build a simple foot roll using only ankle + toe controls

You can achieve a convincing roll even if your rig doesn’t have dedicated foot-roll attributes. Think of the foot in three phases: heel strike → flat → toe-off.

• Heel strike (Contact): rotate the ankle so the heel is down and toe is up. Keep the foot’s position locked where it lands.
• Flat (Down): rotate the ankle toward neutral so the sole contacts the ground. Avoid letting the foot drift forward/back while flattening.
• Toe-off (Up): lift the heel by rotating the ankle, then add toe rotation so the toe stays on the ground a bit longer before it leaves.

Practical toe-off recipe (keyable steps)

Use this as a repeatable pattern on the trailing foot:

• At Contact: trailing foot is already on the toe (heel up).
• At Down: keep toe planted; heel remains up but begins to feel lighter (small changes).
• Between Passing and Up: increase ankle rotation to lift heel higher, then rotate toe downward slightly so the toe stays in contact longer.
• Just before the next Contact: release the toe from the ground (toe rotates up as the foot swings forward).

Key idea: the toe is often the last point to leave the ground. If the whole foot pops off at once, the walk looks floaty.

Keep planted feet locked without special constraints

If you don’t have foot pinning/constraints, you can still lock a planted foot by carefully managing the foot control’s world position:

• When a foot is planted (front foot during down/passing), keep its translation constant in world space.
• Only rotate for roll (heel-to-flat-to-toe) while maintaining the contact point.
• If rotation causes the foot to slide, compensate with tiny translations so the contact point stays fixed.

A quick diagnostic: scrub frames where the foot should be planted and watch the toe/heel contact point against the ground grid. If it drifts, you have foot slide.

4) Align hips and shoulders for natural counter-rotation

Use opposing rotations to show gait mechanics

In a typical walk, the pelvis and ribcage rotate in opposite directions around the vertical axis. This counter-rotation helps the walk feel coordinated rather than stiff.

• At Contact: the pelvis generally rotates slightly toward the stepping leg, while the shoulders rotate slightly toward the opposite arm forward.
• Through Passing: rotations cross through neutral or reduce, then reverse for the next step.

Practical alignment checks

• Hips lead, shoulders follow: keep shoulder rotation slightly delayed or smaller than the hips for a relaxed walk; make shoulders more active for a swagger.
• Keep the spine continuous: avoid a sharp twist at one joint. Spread rotation across pelvis/spine/chest controls if available.
• Head stability: even with torso twist, keep the head from over-rotating unless the character is intentionally looking around.

Simple numeric starting point (adjust to style)

If you like concrete starting values, try small rotations first and scale up:

• Pelvis Y rotation: ~5–10 degrees each side at contacts.
• Chest/shoulders Y rotation: ~3–8 degrees opposite the pelvis.

Then adjust based on attitude: confident walks often have larger shoulder swing; sneaky walks reduce shoulder motion and keep arms tighter.

5) Polish pass: eliminate foot slide, verify arcs, confirm smooth center-of-gravity travel

A. Eliminate foot slide (the fastest credibility win)

Foot slide usually comes from a mismatch between root/pelvis motion and planted foot position. Use this checklist:

• Identify planted ranges: for each foot, mark frames where it should be stationary (typically from contact through part of passing).
• Lock translation: ensure the foot control’s world position is constant during the planted range.
• Adjust root/pelvis: if the character is moving forward, the root must advance exactly one step length per step. If it advances too far, the planted foot will appear to slide backward.
• Re-check after smoothing: spline interpolation can introduce drift. After you spline, re-verify planted frames.

B. Verify arcs (feet, knees, hands, head)

Even a simple walk benefits from clean arcs. You don’t need complex tools—just track the path visually or with motion trails if available.

• Swing foot arc: should travel forward in a smooth curve, lifting enough to clear the ground, then extending to heel strike.
• Knee arc: avoid sudden sideways pops; the knee should track consistently relative to the foot direction.
• Hand arc: arms should swing like pendulums with slight overlap; avoid corners in the wrist path.
• Head arc: should be the smoothest; small vertical motion is fine, but avoid jitter.

C. Confirm smooth center travel (no bumps at pose changes)

To keep the weight transfer readable, make the pelvis/root motion continuous:

• Vertical motion: lowest at down, highest at up, with smooth transitions. If the pelvis “hangs” too long at the bottom, the walk feels heavy; if it snaps up, it feels springy.
• Side-to-side shift: pelvis should drift toward the support leg during down/passing, then transition to the other side for the next step. Keep it subtle unless stylized.
• Forward motion consistency: if walking forward, the root should advance evenly per step. Uneven forward speed reads like limping unless intentional.

D. A practical polish pass order (repeatable workflow)

1. Lock feet on planted frames (translation first, then roll).
2. Fix pelvis path (vertical and side-to-side), ensuring it supports the planted foot.
3. Refine toe-off so the trailing toe is last to leave the ground.
4. Clean swing arcs for feet and hands.
5. Check symmetry: compare left step vs right step for unintended differences (unless character design calls for asymmetry).

Quick self-test: scrub and mute details

Scrub the timeline while focusing only on (1) the planted foot contact points and (2) the pelvis path. If those two read cleanly, the walk will feel grounded even before you add secondary details.