Houdini 21.0 Character KineFX

Multi IK 2.0

Sets up IK chains with more than 3 nodes, or multiple IK chains using segments.

Since 21.0

This component sets up IK chains with more than 3 nodes. It can also set up multiple IK chains in the rig hierarchy.

Multi IK functionality on the arms and legs

See rigging a simple geometry and rigging a character for example uses of this component.

Parameters

Name

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

Settings

Dampen

A larger value dampens the effect of the IK solve, smoothing its snapping effects at the cost of accuracy.

Stretch

A larger value allows more stretch for the IK chain when the target is beyond the length of the chain.

Tracking Threshold

Sets the accuracy of the solve. A higher value is faster but less accurate.

Use Twist

When turned on, uses the pole vector to twist the IK chain.

Use Goal Rotation

When turned on, uses the goal rotation for the target orientation. When turned off, uses the solver’s position for the target orientation.

Resist Straight

When turned on, resists straightening of the IK chain.

Rigid

When turned on, this component behaves like a two-joint IK chain.

Driven

Segments

Segments are tags that separate each IK chain. For example, *Leg loops over tags L_Leg and R_Leg. 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 IK 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. You can specify the individual joints, for example, “L_Hip L_Knee L_Ankle”, or tags that exist on the TransformObject nodes, for example, “#ik & #L_Leg”.

It’s 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 L_Leg tag. So for this component, you can set Driven to “#bind & #L_Leg”.

Driver

Root Name

The name of the root control. If Segments is used, the Segments name is added to the name of the control.

Pole Vector Name

The name of the pole vector. If Segments is used, the Segments name is added to the name of the control.

Tip Name

The name of the tip control. If Segments is used, the Segments name is added to the name of the control.

Pole Vector Offset

The amount to offset the pole vector in the direction of the middle joint (between the root and tip). The IK chain must be slightly bent for this to work.

Level Root

When turned on, sets the root control to world orientation. When turned off, sets the orientation of the root control to that of its associated joint.

Level Pole Vector

When turned on, sets the pole vector to world orientation. When turned off, sets the orientation of the pole vector to that of its associated joint.

Level Tip

When turned on, sets the tip control to world orientation. When turned off, sets the orientation of the tip control to that of its associated joint.

Parent

Root

The parent of the root control(s). When empty, the root control has the same parent as the root node of the IK chain. To unparent the root control, set this parameter to an underscore (“_”).

Pole Vector

The parent of the pole vector(s). When empty, the pole vector is parented to the tip.

Tip

The parent of the tip control(s). When empty, the tip is not parented.

Tags

Root

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

Pole Vector

The tags to add to the pole vector TransformObject nodes created by this component.

Target

The tags to add to the target TransformObject nodes created by this component.

Shape

The APEX Configure Controls SOP provides more options for changing the look of the controls.

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.

Scale

The scale of the control shapes.

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