Preferred Axis Cns

In SOFTIMAGE 3D, an inverse kinematic chain has a preferred axis of rotation. By default, this axis is the z-axis of the chain's root. The chain tries to rotate around this axis when you move the effector in space. In other words, the chain is always as perpendicular as possible to this axis.

The Skeleton->Preferred Axis Cns command in the Actor module lets you change the preferred axis of rotation of a chain, changing its default behavior.

Note:

The general orientation of the chain changes rapidly when you move the effector into the region near the preferred axis constraint.

For more information, see the Constraining Joints and Effectors section of the Animating User's Guide.

Procedure

1. Create an articulated chain using the Skeleton->Draw 2D Chain or Skeleton->Draw 3D Chain command.
2. Create a null.
3. Select the first joint of the chain.
4. Choose the Skeleton->Preferred Axis Cns command and pick the null. The null flashes red and the constraint (dotted line) appears.

Note:

The Skeleton->Up Vector Cns constraint has priority over the Preferred Axis constraint when both constraints are applied to a chain.

Last updated 02-apr-1998