Houdini 21.0 Character KineFX

Neck Head

Sets up the neck and head controls for a character.

Since 21.0

This component sets up the neck and head controls for a character and adds the controls for either a tangent control or a custom setup by the user. This component can be run in a loop over different segments, or parts, of the character.

Parameters

Name

The name to add to the nodes created by this component. When using Segments, the segment name is also added to the nodes.

Settings

Curve

Curve Order

The order of the Bezier curve to build from the CVs (control vertices). Defaults to 2 (linear Bezier curve).

Each segment of a Bezier curve requires that <number_of_cvs> = order. Compound curves share a CV between their curve segments, so each additional curve segment requires an additional order-1 CVs. This requirement can be expressed by the equation <number_of_cvs> % (order-1) == 1.

Order 3 and 4 curves are popular choices for ensuring that each CV has a relatively local impact on the shape of the curve while allowing for the smoothness and flexibility of quadratic and cubic polynomial curves.

Pin Root

When turned on, constrains the orientation of the driven root to the controls. When turned off, the neck solver determines the orientation of the root.

Pin Tip

When turned on, constrains the orientation of the driven tip to the controls. When turned off, the neck solver determines the orientation of the tip.

Add Stretch Control

When turned on, adds an abstract control at the tip control that allows you to adjust the stretch of the neck. See the spline rig component for an example.

Stretch

Type

The type of curve to create from the CVs.

Stretch

Specifies whether to keep the length of the neck. When set to 0, the neck keeps its length. When set to 1, the neck stretches to follow the CV.

Stretch Scale

Controls the amount of stretch. Increasing this value increases the effect of the stretch.

Squash Scale

Controls the amount of squash. Increasing this value increases the effect of the squash.

Keep Tip Scale

When turned on, the scaling at the tip of the neck remains unchanged as you stretch the neck. When turned off, the tip of the neck is scaled as you stretch the neck.

Driven

Segments

Segments are tags that separate each neck chain. Tags can be set up on skeleton joints using an Attribute Adjust Array SOP. See preparing skeletons for rigging for more information.

If Segments is empty, the neck logic is run once.

Note

The Segments parameter does not take APEX path patterns, for example, the %tag() function. Instead, specify the tag names directly in this field.

Driven

The TransformObject nodes to drive, for example, neck_01, neck_02, neck_03. This parameter also accepts APEX path patterns, so you can specify tags in this field, for example, %tag(neck).

It is good practice to also specify the bind tags that are set up by default on the FK transform component’s Tags parameter. The FK transform component is normally the first component that is used to start building a rig. Including the bind tag helps to ensure that you don’t include other controls that might have inherited, for example, the neck tag. So for this component, you can set Driven to %tag(bind) & %tag(neck).

Driver

By default, the neck component sets up a tangent neck with 4 controls - Root Name, Root CV Name, Tip CV Name, and Tip Name. The controls are created automatically using the root and tip as reference. Make sure the control names are unique and don’t conflict with any other controls. You can use the {segment} string when creating multiple neck setups so that there are no naming conflicts (see the Root parameter). The cog control is the main neck control.

Custom

When turned on, creates the specified number of controls, Num Controls.

Num Controls

When Custom is turned on, this is the number of controls to create.

Root Name

When Custom is turned off, this is the name of the root control.

Root CV Name

When Custom is turned off, this is the name of the root tangent CV (control vertex).

Tip CV Name

When Custom is turned off, this is the name of the tip tangent CV.

Tip Name

When Custom is turned off, this is the name of the tip control.

Mid Name

When Custom is turned off, this is the name of the middle control.

End Name

When Custom is turned off, this is the name of the head control, which doesn’t affect the neck.

CV Root Offset

The offset to add to the root tangent CV.

CV Tip Offset

The offset to add to the tip tangent CV.

End Control Offset

The offset to add to the end control.

Scale Inheritance

Sets the scale inheritance of the neck controls.

Promote T

When turned on, promotes the translate component of the neck controls.

Promote R

When turned on, promotes the rotate component of the neck controls.

Promote S

When turned on, promotes the scale component of the neck controls.

Parent

Root

The parent of the root. If left empty, the root is parented to Root's parent. If you are setting up multiple necks, you can leave this field empty. However, you can set parent tags on the guide skeleton, and use the parent tag plus the segment tag to get the correct parent for each segment.

To unparent the root control, set this parameter to an underscore (“_”).

This parameter accepts APEX path patterns, so you can specify tags in this field, for example, %tag(<tag>).

Tip

The parent of the tip. If left empty, the tip is parented to the Root. To unparent the tip control, set this parameter to an underscore (“_”).

This parameter accepts APEX path patterns, so you can specify tags in this field.

CV

The parent of the CVs. If left empty, the CVs are parented to the closest outer control. To unparent the CV controls, set this parameter to an underscore (“_”).

This parameter accepts APEX path patterns, so you can specify tags in this field.

Tags

Component

The tags to add to the neck node created by this component.

Root

The tags to add to the root nodes created by this component.

Tip

The tags to add to the tip nodes created by this component.

CV

The tags to add to the CV nodes created by this component.

Shape

Shape

The shape of the controls. It can be set to any of the built-in APEX control shapes.

Color

The color of the control shapes. To inherit the shape color from the guide skeleton, set this value to (0, 0, 0).

Translate

The translation of the control shapes.

Rotate

The rotation of the control shapes.

Scale

The scale of the control shapes. To inherit the shape scale from the guide skeleton, set this value to (0, 0, 0).

See also

KineFX

Overview

Preparing character elements

Rigging with APEX graphs

Building rig graphs with APEX Script

Rigging with rig components

Animating in the viewport

SOP-based animation

Deformation

Animation retargeting

Pre-H20

Panes

Appendix