Morph between geometry shapes
The Morph tool on the Deform shelf lets you edit geometry at the object level, and automatically creates the necessary Edit and Blend Shapes nodes at the geometry level.
|Blend between shapes|
|Use the Morph tool to set up blend shapes at the object level|
|Make blending between two inputs easier|
|Use a bone angle to control deformation|
Character deformations, especially in the face, often must work with the contours of the deforming surface. Wire deformers make it possible to capture and deform the surface along these contours. You can then deform along the U direction of the curve or animate the shape of the curve to achieve more complex deformations.
How to use a curve to drive deformation
Go to the geometry level containing the surfaces you want to deform.
In the parameter editor , change the curve’s Primitive type to NURBS.
Select the curve, then click to finish the selection.
In the parameter editor, change the Group name to a meaningful name for the deformer. In the network editor , rename the group operator with a meaningful name.
In the network editor, use the tab menu to choose the Wire Capture operator.
Connect the geometry you want to deform to the wire capture node’s first input. Connect the curve’s group node to the wire capture node’s second input.
If you want to put several wire deformers on the same piece of geometry, create a Merge node, connect the curve group nodes to the merge node’s inputs, then connect the merge node to the wire capture node’s second input.
In the parameter editor, click the Capture tab, then click Initialize From groups. This uses the group (or groups) connected to the second input.
Set the U radius and V radius parameters for the curves. These options control the distance within which the curves will influence the geometry.
In the network editor, right-click the wire capture node’s output and choose the Wire Deform operator.
Connect the group (or merge) node’s output to both the second and third inputs of the wire deform node. These inputs control the rest geometry and the deformed geometry.
Turn on the wire deform node’s display flag . In the parameter editor, click the Deform tab, then click Initialize from Rest Groups.
Use the U deform parameter to control how much the curve(s) deform the geometry.
To animate the deformer, you can keyframe the U Deform parameter, and/or animate the shape of the deformer.
You may want to create HUD sliders for the U deform parameter or the blend parameter.
A real face rig will have many wire deformers representing the muscles that control facial expressions. You can promote the various parameters used to control the deformations along the curve, and any blends, up to the character’s digital asset interface for high level access by animators.
How to vary the capture radius along a wire deformer
In the network editor , select the wire capture node.
In the Parameter pane, Alt-click the right text box of the U Radius and lookup parameter to set a keyframe. The channel on this parameter represents scaling of the radius along the length of the curve.
Press on the text field and choose Scope Channels.
In the channel editor, Alt-click somewhere to the right of the existing keyframe to add a second key, then Alt-click again in the center of the channel.
Drag the keys up and down to vary the radii of the wire deformer along its length.
In the Perspective view, you should see the radius along the eyebrow wire adjusting to match the shape of the channel.
The channel defines a lookup table that controls the U radius along the curve. The values for the first and last key on the channel control the start and end of the wire with any internal keys being adjusted along the curve proportional to their position in time.