IK Constraints (help!?)

following this tutorial: http://www.blender3d.org/documentation/htmlI/x7613.html

I’m having problems adding constraints (Figure 38 and surounding area) to the rig.
when I try adding a constraint to the null bone in the fingers and the IK solvers the bones, all the bones move out of place, and nothing in pose mode works like it should.


The null bone is no longer necessary in 2.4x, since you can use the tip of a bone as the last item in an IK chain (replaces the null). Delete the null bones and follow these steps:

Add an IK constraint to the last bone in the finger (Fing3C in Lyubomir’s tutorial) with Ctrl I in Pose Mode. You can choose whether to use a target or not; now any object can be the IK target (Empty, Mesh, whatever); if no target, you will use this same bone to pull the chain around. Notes: A bone with an IK constraint on it will turn brown; Alt-I will remove an IK constraint from a bone.

If you still want to use a separate bone as the target (the tut’s IK_fing3), in the the constraint window enter Object:Armature, Bone:IK_fing3. Make sure this IK target bone is not a child of any other bone in the IK chain; ie don’t extrude it from another bone, just add it in Edit mode. Alternatively, in the Object: field you can enter the name of any object as the IK target.

The other important parameter to set is ChainLen. If zero, this will include all the constrained bone’s ancestors in the IK chain, back to the root. Since moving a finger IK target usually shouldn’t affect everything back to the pelvis, set ChainLen to however many bones you want to affect.

Read Gabio’s Animation Workshop II for more details (see sticky in the Animation forum here).

you say: “Fill in object:<armature name>” which Armature are you talking about?

Whatever Armature your IK target belongs to. If you haven’t changed any names, this is probably Armature. I edited the original post to make this simpler.

Any time you need to specify a bone in Blender for IPO drivers, IK constraints, etc, you have to first tell Blender what armature object it belongs to, then the name of the specific bone.

Thankyou for your help CD38
it all works now