Blend shapes allow you to morph or blend between target shapes within the same topology. They are often used to create and animate character deformations like facial expressions and muscle bulges.

When you import a rig into KineFX, any existing blend shape deformation data on your rig is preserved.

Also, when you combine blend shape animation with skeletal deformation, blend shapes are typically applied before the skeletal deformation.

Example: KineFX network with blend shapes

To view or tweak your rig’s blend shapes and their blend values, you need to add three SOP nodes to your network:

  • The Character Blend Shapes SOP node lets you view your blend shapes in the viewport. This is similar to how the Bone Deform SOP lets you view your character’s skeletal deformation in the viewport.

  • The blend weight values for your character’s blend shapes are driven by detail attributes on the animated skeleton. You can use any SOP to edit these blend shape detail attributes. For example, you can easily set or animate these values directly from the Parameter Editor using the Attribute Expression SOP node.

  • The Bone Deform SOP node lets you append your character’s skeletal deformations to the outputs of your Character Blend Shapes SOP node.

Notes

  • There is currently no tool in KineFX that will let you create new blend shapes.

  • The KineFX export nodes preserve all blend shape data.

How to

To...Do this

View your imported character’s blend shapes

  1. Create a Character Blend Shapes SOP node.

  2. Connect all three outputs from your network’s KineFX character import node to the Character Blend Shapes node’s three inputs.

  3. Turn on the Display flag for the Character Blend Shapes node or the Bone Deform node in your network.

You should now be able to see your rig’s blend shapes in the viewport.

Adjust or key the blend weight values for your blend shapes with a Attribute Expression SOP node

  1. Create an Attribute Expression SOP node.

  2. Connect the third output (Animated Pose) from your KineFX character import node to the Attribute Expression node’s first input, and the Attribute Expression node’s output to the third input (Animated Pose) on the Character Blend Shapes node.

  3. In the Attribute Expression node’s parameters, do the following:

    • In the VEXpressions tab, set Attribute Class to Detail.

    • Add an Attribute VEXexpressions multiparm for every blend shape whose weight values you want to adjust or key.

      The Constant Value parameter for each Attribute VEXexpressions multiparm is the blend weight for each blend shape.

      Example: Multiparms for a network with two blend shapes
  4. For each Attribute VEXexpressions multiparm you added, do the following:

    • Set Attribute to Custom.

    • Select the blend shape channel from the Name parameter’s drop-down list (which lists all the existing attributes from the Attribute Class) or type the name of the blend shape channel into the Name field.

    • Set the Type to Float.

      Blend shape weights or channels are imported into KineFX as floating point values.

    • Type value into the VEXpression field.

    Example: Multiparms for a network with two blend shapes

    Tip

    You can view the names of all the blend shapes on your character from the Geometry Spreadsheet.

    • In the Network Editor, select the Attribute Expression or Character Blend Shapes node.

    • In the Geometry Spreadsheet toolbar, select Animated Pose from the drop-down menu (if applicable) and then turn on Detail attributes.

    Example: Blend shape names in the Geometry Spreadsheet
  5. For each Attribute VEXexpressions, adjust and/or key their Constant Value parameter values to achieve the deformation effects or animated deformations you desire.

    Example: Constant Value parameters
    Example: Adjusting the blend shape weight values

View the blend shape’s targets

  1. Create a Visibility SOP node.

  2. Connect the first output (Rest Geometry) from your network’s KineFX character import node to the input on the Visibility node.

You should now be able to see the targets for your rig’s blend shapes in the viewport.

See also

KineFX

Procedural Rigging

Animation Retargeting

Panes