-and I want them to obey the following rules. Bone D can be freely rotated, and moved (within the limits imposed by B and C) by grabbing its handles and translating, rotating etc. B and C should follow it but not A, like this-
D should not rotate under the influence of the B and C chain. However, if I translate/rotate Bone A the whole chain including D should follow it, like this-
I’ve got most of it by putting an IK on D, with no target (I admit as a noob to being rather baffled by what targets are, since selecting anything as one seems to just mess up the chain). But the last part- everything following Bone A, doesn’t work properly. Translating does (everything moves) but rotating doesn’t- Bone D does not rotate with A and the rest of the chain. And I’m at my three attachments limit, so you’ll just have to imagine that
I’m sure this must be simple to do when you know how, but as a naive user it is not obvious to me how to proceed.
If I have understood you correctly, You want A to stay still when you move D yes? If so what I have attached should cure the problem.
Points to note:
IK constraints NEED a target, that’s why the IK constraint is red or “duff”, which can be a mesh or a bone within an armature. They can only be IK’ed to the Tail of a bone (the fat end).
If you want to MOVE bone D. it’s tail most be free, i.e. not connected to another bone, therefore it must be the other way round, with its tail free.
If you want to IK a bone to the head of bone D, which you do, you must extrude it to get a connected bone tail to IK to (Bone-D.IK in my file, its length is immaterial.
If you want bone A to stay still, you should lock the IK stretch properties in the Bones Pane/Inverse Kinematics section as I have done in this blend file. Varying these amounts can cause restricted or “stiffened” rotations, uncheck the Lock button and type a value between 0 and 1 or just drag a value to see the effect of stiffness on your bone (ooer missus!).
If you want to rotate or move the whole lot, simply move or rotate the whole armature in Object Mode - or parent it to another armature/Empty/Mesh and animate that. Or add drivers/keyframes to the Armatures Object Pane/Tranform variables.
If you want to Rotate bone D about some point, other than its tail, insert another bone with it’s tail at the centre of rotation and parent Bone-D to it so it inherits rotation, then rotate or grab this bone.
See the attached blend file, just grab (key g) bone D in Pose Mode and drag it around the screen.
Thanks, but I’m afraid that is not what I’m trying to do. In your file, if I move Bone A, bone D is stuck in place due to the extra bone. I want the whole chain to move around with A. Also I don’t want another bone to control Bone D, I want to have control of D itself. I don’t care whether I use IK or some other set of constraints, I’m just not sure what set of constraints will achieve my desire.
bone A controls the whole chain. Bone D can move around and drag B and C with it. It can also be arbitrarily rotated without affecting them. The only thing wrong (other than the red IK ) in this rig is that if you rotate A around its tail, although the chain follows it, D does not inherit A’s rotational orientation.
bone A controls the whole chain. Bone D can move around and drag B and C with it. It can also be arbitrarily rotated without affecting them. The only thing wrong (other than the red IK ) in this rig is that if you rotate A around its tail, although the chain follows it, D does not inherit A’s rotational orientation.
It cannot inherit rotation from A because it is not and cannot be, connected and parented to it!
I’ll have another look at it.
OK I’ve looked - Bone D does not inherit rotation from Bone C - just check this and it rotates with A, BUT, your IK is still wrong so I’ll look at this next. I have put some extra stuff about rotating the whole armature in the post above.
OK - now it’s technically correct, and what you want - I think Just use Bone - “control” to move or rotate bone D.
If you leave an incorrect IK constraint - you will get problems later on. BTW XYZ Euler is the better bone format for rotations, rather than Quaternion, so I am told.
) in this rig is that if you rotate A around its tail, although the chain follows it, D does not inherit A’s rotational orientation.
Just use Bone - “control” to move or rotate bone D.