Unity - Scripting API: AnimatorCondition

struct in UnityEditor.Animations

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Description

Condition that determines if a transition is taken.

Animator conditions represent a comparison between an animator parameter and a threshold value. When a condition is assigned to a transition, the animator evaluates the condition to determine if the transition is taken. When the condition is true, the transition is taken.

A condition is made of three parts: a comparison mode, a parameter name, and a threshold. The parameter is compared to the threshold using the comparison. The parameter is always to the left of the comparison. For example, a condition with a comparison of Greater evaluates to true if the parameter is greater than the threshold.

Not all parameter types are compatible with every comparison modes. If you attempt to use a parameter type with an incompatible comparison mode, an error occurs. Parameters types and their compatible comparison modes are as follows:

For float parameters, the Greater and Less modes are compatible.
For int parameters, the Greater, Less, Equals, and NotEquals modes are compatible.
For boolean parameters, the If and IfNot modes are compatible.
For trigger parameters, the If mode is compatible.

Note that when the comparison mode is If or IfNot, the threshold value is ignored.

The following example adds a menu that creates a state machine in the Editor. It uses animator conditions to control when a transition is taken.

using UnityEditor;
using UnityEditor.Animations;
using UnityEngine;

public static class AnimatorConditionExample
{
    [MenuItem("Example/CreateFancyController")]
    static void CreateController()
    {
        AnimatorController controller = new AnimatorController();
        controller.AddLayer("Locomotion");

        AnimatorState stateWalk = controller.layers[0].stateMachine.AddState("Walk");
        AnimatorState stateJump = controller.layers[0].stateMachine.AddState("Jump");
        AnimatorState stateDead = controller.layers[0].stateMachine.AddState("Dead");

        controller.AddParameter("StartJump", AnimatorControllerParameterType.Trigger);
        controller.AddParameter("Health", AnimatorControllerParameterType.Int);

        controller.layers[0].stateMachine.AddEntryTransition(stateWalk);

        // Use the conditions property to get the current conditions or set new ones.
        // Here, the state machine transitions from walk to jump if the StartJump trigger is set.
        // Because this is an If condition mode, you don't have to set a threshold value.
        AnimatorStateTransition transitionWalkToJump = stateWalk.AddTransition(stateJump);
        transitionWalkToJump.conditions = new[] {
            new AnimatorCondition
            {
                mode = AnimatorConditionMode.If,
                parameter = "StartJump",
            }
        };

        // Transition to dead if the healh parameter is below 1
        AnimatorStateTransition transitionWalkToDead = stateWalk.AddTransition(stateDead);
        transitionWalkToDead.conditions = new[]
        {
            new AnimatorCondition
            {
                mode = AnimatorConditionMode.Less,
                parameter = "Health",
                threshold = 1,
            }
        };

        // Consider using AddCondition as a shorthand to add a new AnimatorCondition to the conditions list
        AnimatorStateTransition transitionJumpToDead = stateJump.AddTransition(stateDead);
        transitionJumpToDead.AddCondition(AnimatorConditionMode.Less, 1, "Health");

        // If no conditions are specified, the transition must have an exit time to be valid
        AnimatorStateTransition transitionJumpToWalk = stateJump.AddTransition(stateWalk);
        transitionJumpToWalk.hasExitTime = true;

        AssetDatabase.CreateAsset(controller, AssetDatabase.GenerateUniqueAssetPath("Assets/FancyController.controller"));
    }
}

Properties

Property	Description
mode	The equality or comparison operator to evaluate the condition with.
parameter	The name of the parameter used in the condition.
threshold	The AnimatorParameter's threshold value for the condition to be true.