Dynamic spline IK chain illustrated using a butterfly tail

In this scenario a dynamic spline IK chain is created and used on a dragonfly-type bug model. As the dragon bug moves about, its tail wiggles slightly.

To play the animation, click the link below.

dragonbug.mov

To create a dynamic spline IK chain

1. Create a new scene and switch to the Side orthographic view.
2. In the Animation menu set, select Skeleton > Joint Tool.
3. To draw a tail in a rest position, as shown in the image below, click near the top of the Y-axis and then click to create joints as though they were along the tail. At the last joint press Enter.
   
4. Select Create > CV Curve Tool and trace a curve over the joints, clicking at each joint to create a CV. Press Enter at the end of the last joint.
5. With the curve selected, in the Dynamics menu set, select nHair > Make Selected Curves Dynamic.
6. Select nHair > Display > Current Position.
7. To attach the curve into the chain, in the Animation menu set, select Skeleton > IK Spline Handle Tool > .
8. In the IK Spline Handle Settings editor, turn off Auto Create Curve.
9. Follow the instructions in the Help Line, which are:
   • Click the start joint.
   • Click the end joint.
   • Click the Current Position curve.
10. To select the follicle, do the following:
    • Select the curve.
    • Select the follicleShape in the Attribute Editor.
    • Click the Select button at the bottom of the Attribute Editor.
11. In the follicleShape, set Point Lock to Base.
12. To play the simulation, select nSolver > Interactive Playback.
13. To stabilize the dynamic curve’s behavior, adjust the Bend Resistance attribute value in the Dynamic Properties section of the hairSystemShape of the Attribute Editor.

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