◻️Step Modifier

Overview

Step Modifier creates procedural steps to avoid feet sliding when changing animation states (e.g., standing to crouching).

Bone References

Here you will find bone references to assign.

• Pelvis is the character pelvis or hip bone.

• Right and Left Foot IK Target: is the IK bone for the right or left foot. It's usually set to IK foot_r or IK foot_l.

Ground Alignment

Here you will find settings for snapping feet to the ground.

• Right Foot is the character right foot bone (not an IK).

• Left Foot is the character left foot bone (not an IK).

• Leg Stretch Factor fine-tunes how aggressively the system detects and corrects leg stretching. Higher values increase the likelihood that a leg will be classified as “stretched” and have its length adjusted accordingly.

Step Motion

Here you will find animation curves for feet and pelvis.

• Lead Foot Motion is the position animation for the leading foot (the one making a step first).

• Follow Foot Motion is the position animation for the following foot (the one making a step after the leading one).

• Pelvis Motion is the position animation for pelvis.

Note: The Animation Curve values must at end zero for all motions.

• Lead, Follow Foot and Pelvis Scale are values that will scale each motion per-axis. For example, the X component will scale the X axis.

• Play Rate is the speed multiplier for this step motion.

Stride Settings

Here you will properties that define the procedural step.

• Animated Lead Foot defines the leading foot for this step. A leading foot is the one making a step first.

• Force Lead Foot controls if the step must always start with a leading foot. If disabled, the leading foot will be determined based on the velocity vector.

• Max Allowed Strength defines the max allowed step length. If exceeded, feet will be moved in the movement direction to avoid stretching.

• Max Allowed Offset Angle defines the max allowed character rotation to avoid leg twisting. If exceeded, feet will be rotated around pelvis to compensate the rotation.

• Step Cooldown Rate is the time in seconds needed to pass before making the next step.

Use-cases

Step Modifier can be used for any situation to replace feet sliding with a nice procedural step. Here are most popular applications:

1. Movement stop or start transitions.

2. New stance transition (e.g., going from rifle to sword, or from standing to crouching).

3. Turning in place.

Tip: CAS comes with example Step presets, these can be found in KINEMATION/CharacterAnimationSystem/Examples/Steps/.

Recommended settings

To get best results, make sure that:

1. MaxAllowedStride is set to ~0.3-0.4 to avoid character legs being strecthed. Setting this to a too small number will result in abrupt, unnatural steps.

2. MaxAllowedOffsetAngle is set to ~45 degrees to avoid legs being twisted.

3. StepCooldownRate is set to ~0.3-0.4s to handle player input-spamming situations.

4. Force Lead Foot can be used for specific cases, like turning in place — we only want to turn right with the right foot, and vice versa.

5. All animation curves start at zero for a seamless transition.

These settings might differ from one character model to another, so it's fine to experiment and find what works best for your character.

How to play steps

Steps can be played at runtime using by updating the animation modifier:

YourComponent.cs

private ProceduralAnimationComponent _proceduralAnimation;
private StepModifierSettings _yourStepModifier;

private void YourMethod()
{
    _proceduralAnimation.UpdateAnimationModifier(_yourStepModifier);
}

It's possible to play steps when a transition is entering or exiting a state in the Animator:

Syncing steps with animation states.

This feature is used in the CAS Demo to play steps when turning in place or finishing climbing.