Keyframe

Description

A keyframe that can be injected into an AnimationCurve.

Keyframes are used to control how the value of an AnimationCurve changes over time. Each Keyframe is determined by its position in the AnimationCurve through the Keyframe.time (horizontal axis) and Keyframe.value (vertical axis) properties. You can control how interpolation is handled between different Keyframes and the AnimationCurve slopes through the Keyframe.inTangent, Keyframe.outTangent, Keyframe.weightedMode, Keyframe.inWeight and Keyframe.outWeight properties. Note that unlike what the Keyframe.time property name might imply, it is not actually tied to time and can simply be thought of as a position on the horizontal axis of a two-dimensional space.

Hermite Segment

When both keyframes weightedMode are set to WeightedMode.None, the curve segment is interpolated using a Hermite curve algorithm. Hermite evaluates faster than Bezier and is the default weightedMode for a Keyframe.

Bezier Segment

Setting weightedMode will change how the neighbouring segments are interpolated. Weighted segments are interpolated using a Bezier curve algorithm. For a given weighted keyframe, the interpolating function uses the Keyframe.outWeight value and the next keyframes Keyframe.inWeight alongside both keyframes values to calculate the curve. If no weight is set (when either keyframe Keyframe.weightedMode is set to WeightedMode.None), then a weight value of 1/3 is used.

Additional resources: AnimationCurve.AddKey, AnimationCurve.keys, AnimationCurve.Evaluate.

using UnityEngine;

//This script makes the GameObject move back and forth from -5 to +5 on the x-axis
public class KeyFrameExample : MonoBehaviour
{
    AnimationCurve  animCurve = null;

    void Start()
    {
        Keyframe[] ks = new Keyframe[2];

        ks[0] = new Keyframe(0f, -5f); //Create a Keyframe at time 0 with a value of -5f

        ks[1] = new Keyframe(1f, 5f); //Create a Keyframe at time 1 with a value of 5f

        animCurve = new AnimationCurve(ks);
        animCurve.postWrapMode = WrapMode.PingPong; //Set the WrapMode to PingPong in order to make the GameObject go back and forth
    }

    void Update()
    {
        if (animCurve != null)
            transform.position = new Vector3(animCurve.Evaluate(Time.time), 0.0f, 0.0f);
    }
}

Properties

Constructors