Anim Layer Masks and Blending

Today, we are releasing the latest anim component feature: the masking and blending of anim layers. 

This is a versatile feature that has been hotly requested by PlayCanvas developers that wish to get even more creative with their animations. We’re excited to be able to share how it works in this blog.

Animating characters

When creating complex animation behavior for games, it is often necessary to make a character carry out multiple actions at once. For instance, you might want to create a character that can pick up and carry an item, or shoot a weapon while freely moving around a scene. 

To perform these actions at the same time, the upper and lower body of the character must be animated independently. The upper body should be able to move from an idle stance to a shooting stance, and then shoot on demand, all while the lower body moves between idling, walking, running based on the player’s command.

A character with two animation layers. A movement layer and a shooting layer masked to the upper body

This effect can be difficult to achieve in most 3D engines, as it usually requires removing certain animated bones in the animation files themselves, before importing those assets into a game project. Only then would a developer be able to create two animation layers, one for movement and another for shooting. 

A shooting animation might have all of its lower body bones removed, which would free up the lower body to be animated by the movement layer. In large projects, this can start to become really cumbersome. Adding or removing bones from an animation would require a rebuild of the animation asset in whichever modelling software the developer is using, followed by a reimport of the asset into the PlayCanvas project.

Anim Layer Masks

Masks can streamline this workflow by enabling developers to add or remove a model’s bones from an animation layer directly. This means you can select which part of a character a particular set of animations should animate directly in the PlayCanvas editor. Testing out different combinations of character bones now becomes as simple as toggling a few checkboxes.

Creating layer masks in the PlayCanvas editor

By selecting only the bones in the upper body of the character model for an anim layer, you can free up the lower body to be animated by previous layers which would have been overwritten without this upper body mask.

Anim Layer Blending

Previously when using the anim component, you could play any number of animations on top of each other by creating multiple anim layers. However, any animations from subsequent layers that animate the same bones as previous ones will completely overwrite those previous animations. 

That meant that even if you were to add a shooting animation to the top half of a character, it would always be playing over a walking animation that was placed on a previous layer. 

Now with anim layer blending, it is possible to smoothly blend subsequent layers in and out, changing the weight each layer contributes to the characters animation in real time.

Animation layer blending in the PlayCanvas examples browser

When editing an AnimStateGraph asset, you’re now presented with two `Blend Type` options in each layer. The `Overwrite` option is set by default and works as before, each subsequent layer completely overwrites the animation values of previous layers. 

However, now, if you select the ‘Additive’ option, the anim system will take the weight of each additive layer into account and blend the layered animations accordingly. This is a great way to blend one animation on top of another.

Useful Links

We’re really keen to see what you can create in PlayCanvas using this feature, so be sure to check out the links below so you can begin working with layer masks and blending.

Introducing the Anim State Graph

We’re excited to be able to release a new system for creating fantastic and high fidelity animations in PlayCanvas!

Animation systems receive a set of inputs (button presses, current player speed, health, etc) and output a models animation pose for the current frame. How an animation system goes from a particular set of inputs to the desired animation pose can become quite complicated, especially when writing this in code.

With the release of the Anim component, Anim State Graph assets and Anim State Graph Editor, you will be able to design and develop intricate animation behavior for your game objects right in the PlayCanvas editor. 

It’s now easier than ever to make your game characters move just the way you’d like, while writing minimal code in the process!

Having recently beta tested this feature with a number of developers, we’ve already seen some fantastic results! For instance, the developer of the popular online shooter is utilising the anim state graph to drive character animations in their up and coming online RPG. 

A clip of an early build of this game can be seen below, showcasing the blending of multiple animation clips. When combined together in a state graph they create realistic and fluid movement for the main character.

This animation system was entirely developed in the PlayCanvas editor using the anim state graph user interface. The state graph for the main character can be seen below:

We can’t wait to see what other developers can create with this system!


Graph Layers – Split your animation behavior into separate layers. For instance: locomotion animations can be separated from facial expressions. 

Multiple characters – Because anim state graphs are stored as assets, a single graph can be used to drive the animation of as many entities as you want by assigning your graph asset to multiple entity anim components.

Multiple characters utilising the same anim state graph

While these two characters use different animations for their various actions, they share the same behavior. With the anim state graph you can update this behavior in one place while still using it with as many characters as you like.

How does it all work?

When opening an Anim State Graph asset you’ll be presented with a visual graph editor which allows you to define all of the different animation states your game object can be in. You can then connect these states using transitions. 

Create anim state graphs using the editor ui

Each transition blends between two animations over a specified amount of time. You can adjust and tweak transitions to your liking and see the results in real time in the PlayCanvas launch page. You can then assign parameter conditions to each transition to define the circumstances under which that transition can fire. These parameter values can be modified in your scripts to control the behavior of your animation system.

Control anim state graph behavior in scripts using the anim component API

Once you’ve created your Anim State Graph you can assign it to your entity using the Anim component. At this point you can attach your animation assets to each state which will play when transitioning to that state.

Looking ahead

Today only marks the initial release of our new animation system. We’ve got grand plans on how to push the system further. Here’s a few features we’ve got in the works:

Animation Events – These events can be set up to fire and specific points during the lifetime of an animation, allowing you to hook game logic into the behavior of your anim state graph. For example you could spawn a set of dust particles during the exact frame that your character lands on the ground after a jump.

Layer Masking – You’ll be able mask your character animations on a particular state graph layer. For instance you could have only the bottom half of a character driven by a particular anim state graph layer.

Blend Trees – Directly control the blend between multiple animations in real time.

Blending three animations using a 2D cartesian blend tree

Animation Clips – Currently the anim state graph supports animation assets that have been imported into PlayCanvas. Clips will allow you to create extra animation assets within the PlayCanvas editor yourself! These will be great for quickly adding smaller animated flourishes to your game objects.

If you’re interested in using anim state graphs in your PlayCanvas projects, here’s some useful links:

Introducing JSON Script Attributes

JSON Script Attributes Preview

We have levelled up the Script Attributes that makes it much easier to organize and group related attributes together.

Using JSON, developers are able to define a schema for a data object that has multiple attributes and have them grouped together in the Inspector.

In the example below, we have created a JSON schema with the name ‘settings’ and has the attributes ‘gravity’, ‘startingHealth’ and ‘godMode’.

GameManager.attributes.add('settings', {
    type: 'json',
    schema: [{
        name: 'gravity',
        type: 'number',
        default: -9.8
    }, {
        name: 'startingHealth',
        type: 'number',
        default: 20
    }, {
        name: 'godMode',
        type: 'boolean',
        default: false

In the Inspector, the data object is shown as a collapsible section:

Collapsible script settings

Even better, these data objects can made into an array! This is a huge improvement over having to organize multiple attribute arrays that was difficult to update and error prone to maintain.

Example JSON schema for an array of enemies:

GameManager.attributes.add('enemies', {
    type: 'json',
    schema: [{
        name: 'health',
        type: 'number',
        default: 10
    }, {
        name: 'type',
        type: 'number',
        enum: [
            { 'Close Combat': 1 },
            { 'Range': 2 },
            { 'Both': 3 }
    }, {
        name: 'templateAsset',
        type: 'asset',
        assetType: 'template'
    array: true

Becomes the following in the inspector which is so much cleaner!

Arrays of JSON objects

Read more in the documentation and let us hear your feedback in the forums!