When developing Animation Blueprints for characters in Unreal Engine, it can be helpful to implement dynamic movement and locomotion variables to control animation behaviors.
This document will explain how to set up the EventGraph Animation Blueprint logic to calculate these variables in your own project. In addition, this document will also provide an explanation of how to calculate these variables in a thread safe blueprint function, using property access nodes to increase your projects performance and stability.
Prerequisites
- A controllable Third Person Character with a movement component.
You can supplement this requirement with the Third-Person template project if needed.
Character Object Reference
Most animation variables can be calculated using the character's movement component in the EventGraph. In order to use the character's movement component to calculate other animation variables, a reference variable must be created.
First, in the EventGraph of the character's Animation Blueprint, create an Event Blueprint Initialization Animation node.
From the Event Initialization node, create a Cast node that casts the animation blueprint to the character's blueprint.
In the workflow example, the character's blueprint is the BP_ThirdPersonCharacter found in the Third Person template project.
Then create a Get Owning Actor node and connect the Return Value output pin of a to the Cast node's Object input pin.
Next, right-click the cast node's As Character output pin and select the Promote to Variable option from the context menu, to create a character object reference variable.
After connecting the logic, a character object reference variable is accessible in your blueprint's EventGraph and AnimGraph.
Movement Component Reference
In order to isolate the character's Movement Component from the Character Object, a Get Character Movement node is needed. From the Set Character variable node's Character output pin, create a Get Character Movement node.
Next, right-click the Character Movement output pin to a variable, and select promote to variable from the context menu, to create a movement component reference variable.
After connecting the logic, a character movement component reference variable is accessible in your blueprint's EventGraph and AnimGraph.
Velocity
A character's velocity can be a helpful value to use when calculating animations that require direction or speed.
To create a velocity variable in the EventGraph, first create an Event Blueprint Update Animation node.
Next, add the Movement Component reference variable to the EventGraph. Then, you can use a Get Velocity node, to calculate the vector value that represents the movement component's direction and magnitude of movement.
Next, right-click the Velocity output of the Get Velocity node and select the Promote to Variable option from the context menu to create the velocity variable.
After connecting the logic, a Velocity variable is accessible in your blueprint's EventGraph and AnimGraph.
Here, a Print String node is sending a debug message every frame with the updated X, Y and Z values of the character's velocity.
Thread Safe
First create a new thread safe function in your character's animation blueprint.
Then, right-click in the graph to create a property access node.
From the property access node's drop down menu select the function, Try Get Pawn Owner > Get Movement Component > Velocity. Then right-click the vector output pin and select promote to variable, to create a velocity variable.
After connecting the logic, a Velocity variable is accessible in your blueprint's EventGraph and AnimGraph.
In order to update this function during your project's runtime, add the thread safe Velocity function to the Blueprint Thread Safe Update Animation graph.
Your character's Animation Blueprint now calculates the character's velocity in a thread safe manner.
Character Speed
Character movement speed can be a helpful variable to use when selecting animations based on a character's speed, such as running or walking states.
You can create a Vector Length XY node from the velocity variable to isolate the character's speed from the movement component velocity.
Next, right-click the Vector Length XY node's Return Value output pin to select Promote to Variable from the context menu.
After connecting the logic, a Speed variable is accessible in your blueprint's EventGraph and AnimGraph.
Here, a Print String node is sending a debug message every frame with the updated value of the character's speed.
Thread Safe
First create a new thread safe function in your character's Animation Blueprint.
Next, create a property access node and select the Try Get Pawn Owner > Movement Component > Velocity function from the drop-down menu.
From the property access node's output, create a Vector Length XY node to extract the forward and lateral motion (X and Y axis).
In order to update this function during your project's runtime, add the thread safe Speed function to the Blueprint Thread Safe Update Animation graph.
Your character's Animation Blueprint now calculates the character's velocity in a thread safe manner.
Movement Threshold
To control when your character's movement should trigger animation playback, you can create a Movement Threshold variable that will allow movement when the character's speed reaches a set magnitude.
From the character's speed variable in the EventGraph, create a Greater Than or Equal To (>=) node and set the value to a low number.
This number can be a very small value like 0.1.
Right-click the boolean output pin of the Greater Than or Equal To (>=) node, and select Promote to Variable from the context menu.
After connecting the logic, a Movement Threshold variable is accessible in the Animation Blueprint's EventGraph and AnimGraph.
Here, a Print String node is sending a debug message every frame with the updated state of the character's movement threshold variable.
Thread Safe
First, create a new thread safe function in your character's Animation Blueprint.
Create a property access node in the thread safe graph, and set the node to Try Get Pawn Owner > Movement Component > Velocity. Extract the forward and lateral movement with the Vector Length XY function node.
Then with a Greater Than or Equal To (>=) node, set the speed threshold at which movement animation should not occur.
This number can be a very small value like 0.1.
Right-click the boolean output pin of the Greater Than or Equal To (>=) node, and select Promote to Variable from the context menu.
In order to update this function during your project's runtime, add the thread safe Should Move function to the Blueprint Thread Safe Update Animation graph.
Your character's Animation Blueprint now calculates the character's movement threshold variable in a thread safe function.
Jumping and Falling
You can use a Jumping and Falling variable to determine when to play jumping and landing animations in the character's AnimGraph.
First create a Movement Component variable into your Animation Blueprint's EventGraph.
You can now create a IsFalling function node from the movement component reference variable node.
Right-click the Is Falling node's Return Value output pin, and select the Promote to Variable Option from the context menu.
After connecting the logic, a Jumping and Falling variable is accessible in the Animation Blueprint's EventGraph and AnimGraph.
Here, a Print String node is sending a debug message every frame with the updated state of the character's Jumping and Falling variable.
Thread Safe
First create a new thread safe function in your character's Animation Blueprint.
Create a property access node and set the node to Try Get Pawn Owner > Get Movement Component > IsFalling.
Right-click the property access node's output pin and select the Promote to Variable option from the context menu.
In order to update this function during your project's runtime, add the thread safe Is Falling function to the Blueprint Thread Safe Update Animation graph.
Your character's Animation Blueprint now calculates the character's jumping and falling state variable in a thread safe function.
EventGraph Reference
Here you can reference the full Event Blueprint Update Animation logic in the EventGraph used in the example workflow.
