Weight Type Weights are useful if you have constrained an object to more than one other object. This way you can weight the different constraints, so that a constrained object tends to meet one constraint more than another. Weights are animatable. Higher weight values make the IK problem stiff, and harder to solve. Goal Type Position Selects the rotate pivot position of the joint.
Orientation Selects the same orientation as the object.
Both Selects both the position and orientation. As shown in the following diagram, this option creates an extra joint beside the IK handle. Options Position Type Spline handles can define positions on a curve either by parameters or by arc-lengths. Both types of measurements use relative percentage values. See the Introduction to the IK on page 180 for more information.