This option lets you control the handle's orientation in world space. This means that the rotation-plane is controlled by an IK handle can be fixed in world space instead of relative to the root joint. You can also set this attribute from the Information Window after it is created. 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.