Note: This refers “Rigging a Hand and Foot” from the Blender 2.3 documentation.
The arms on my model are both IK chains and are difficult to pose.
For example, to place a hand in a certain position requires moving the hand IK to the final position. The hand assumes an accurate position but then the wrist rotation and elbow placement can be wrong. To rotate the hand requires rotation of the shoulder IK which rotates the upper arm --> lower arm --> hand. However, the elbow can be moved.
My first solution, after frustrating myself for an hour last night working with an IK chain, was to break the movement into pieces. First bring the hand in front of the torso in side view. Then place the hand in front of the face in front view. Then rotate the shoulder IK in top view. Needless to say, this is very slow.
Reading recent posts has led me to question my use of IKs as the animation is essentially constructed by keyframing. I suspect that using FK chains would allow more precise placement of my model and reduce animation time.
Can more experienced users please post their opinions on the matter? Which is the preferred method when complex motions must be animated for humanoid characters: FKs or IKs? What are the advantages of choosing one over the other?
Lastly, if FKs are preferred, how can I convert my existing arms from IK to FK? Is deletion and re-rigging of new arms necessary? I spent quite a bit of time on rigging the hands (learning by doing) and am reluctant to begin again.