Page 988 - Kitab3DsMax

Part IX: Working with Characters
The IK Solver Properties rollout also includes Threshold values. These values determine how close the end
joint and the goal must be before the solution is pronounced valid. You can set thresholds for Position and
Rotation. The Iterations value sets the number of times the solution is tried.
Tip
Setting the Iterations value to a higher number produces smoother (less jerky) results, but it increases the time
required to find a solution. n
Displaying IK controls
The IK Display Options rollouts can enable, disable, and set the size of the gizmos used when working with
IK solvers. Using this rollout, you can Enable the End Effector, the Goal, the Swivel Angle Manipulator, and
the IK solver (which is the line connecting the start and end joints).
Tutorial: Animating a puppet with the HI IK solver
The HI solver is probably the best solver to use for animating characters. This fine fellow made of bones
makes a good candidate for trying out the HI solver.
To animate an alligator with the HI IK solver, follow these steps:
1. Open the Dancing puppet.max file from the Chap 38 directory on the DVD.
This file is the same file that was created using the bones system.
2. Apply the HI solver to the arm chains by selecting the left upper arm and choosing
Animation ➪ IK Solvers ➪ HI Solver. A dotted line appears in the viewports extending from the
selected object. Move the cursor over the left hand object, and click.
3. Repeat Step 2 for the right arm and both leg chains.
4. Click the Auto Key button, and drag the Time Slider to frame 20. Select the goal for the left leg IK
chain, click the Select and Move button on the main toolbar (or press the W key), and move the
left leg goal upward.
5. Repeat Step 4 for frames 40, 60, 80, and 100, moving the various IK chains in different directions.
6. Move the Time Slider to frame 50, and select all objects by choosing Edit ➪ Select All (Ctrl+A).
Then drag all the objects upward a short distance. Drag the Time Slider to frame 100 (or press the
End key), and drag all the objects back down again.
7. Click the Play Animation button (/) to see the resulting dance.
Figure 38.8 shows one frame of the dancing puppet.

History Dependent IK solver
The History Dependent (HD) IK solver takes into account the previous keyframes as it makes a solution.
This solver makes having very smooth motion possible, but the cost of time to compute the solution is
increased significantly. You can also assign this IK solver to bones systems by specifying the History
Dependent solver in the IK Chain Assignment rollout or by choosing Animation ➪ IK Solvers ➪ HD Solver.
This IK solver shows up as a controller in the Motion panel when the IK chain is selected. The settings are
contained in a rollout named IK Controller Parameters, which is visible in the Motion panel if you select
one of the end effector gizmos. The end effector gizmo is the object that you move to control the IK chain.
It is displayed as a set of crossing axes.

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