Combining Layers Using Direct Blend Trees

Due to the high performance impact of Animator Layers in an Animator Controller, it is often a lot better to combine things such as toggles and radial menus into a single Animator Layer by using a Direct Blend Tree.

Understanding Direct Blend Trees

Direct Blend Trees allow you to assign a parameter directly to each Animation or Blend Tree child, instead of blending between them. This allows you to animate more than one thing at the same time in the same Blend Tree.

For VRChat, we can abuse this behaviour to create multiple toggles and radial puppets within a single Direct Blend Tree, similar to how we would in separate Animator Layers.

The structure and functionality of a Direct Blend Tree is very similar to that of an Animator Controller, so it might be easier to understand them if you look at them as if they were Animator Controllers. This is a very simplified way to look at and understand Direct Blend Trees, so it should be noted that while they are very similar to Animator Controllers, they are NOT the exact same!

<aside> ⚠️ There are a few key differences between the two which heavily limit the use cases and implementations of Direct Blend Trees compared to Animator Controllers. More info can be found in the Current Limitations And Known Issues section.

</aside>

A Direct Blend Tree with 3 Clothing Toggles

Creating Toggles And Radial Puppets

Making toggles and radial puppets in a Direct Blend Tree is not much different or any more difficult than creating a regular toggle in an Animator Layer.

Step 1

• Create a new Animator Layer and right click in any empty space to create a new Blend Tree State

• Set the Write Defaults value of the Blend Tree State to ON! This is necessary! We will go into detail about why under the Write Defaults section

Step 2

• Double click or right-click the Blend Tree State to open it
• Select the Blend Tree and, in the inspector, change the Blend Type to Direct

Step 3

• Add a new Blend Tree as a child to the Direct Blend Tree
• If you do not already have one, create a new float ****parameter in your Animator Parameters list and set its value to 1
  • In this example, the parameter is called Weight
  • This is not the parameter that will be used for your toggle itself, it is a separate parameter that sets the weight of the child to 1 so it fully animates, similar to how you set the weight of an Animator Layer to 1
• Set the parameter of the child to the float parameter.
  • You can re-use this float parameter for all the children, you do not need to create a new one for each child
• Make sure the Direct Blend Tree has Normalized Blend Values unchecked.

Step 4

• Select the child Blend Tree and make sure the Blend Type is set to 1D
  • You can rename the Blend Tree at the top of the inspector for organizational purposes
• Create a new float parameter for the toggle or radial puppet you are creating, and set it as the parameter of the current child 1D Blend Tree
• Add two new motions as children to this child 1D Blend Tree and put in the same animations you would typically use for your standard toggle or 1D radial puppet
  • If you are used to utilizing single animation clips with Motion Time for your radial puppets, you will have to make your animation clips in 1D Blend Tree radial puppet fashion instead

<aside> ⚠️ Using only one animation clip like you would with a WD On workflow will not work! You need separate animation clips or a combined clip.

</aside>

Step 5

• Add the parameter that is used by the 1D Blend Tree to your VRChat Expression Parameters List
  • If you are making a radial puppet, set the type to float
  • If you are making a toggle, set the type to bool
    • This will work due to Expression Parameter Mismatching

An example of combining multiple radial puppets and toggles can be found at Direct Blend Tree Toggle.

Repeat steps for every toggle and radial puppet you want to create, there is no limit to how many you can add.

An example of combining multiple radial puppets and toggles can be found at Direct Blend Tree Radials and Toggles.