Hi. What is the difference between the usual bone constraint and the “IK bone constraint” please? Why are there two? Why doesn’t blender just have one? Don’t they do the same thing?
Thanks in advance!
Him tim. I think it’s because it allows movements of bones within an IK chain to be restricted when moving them individually and an IK constraint can be added in addition which constraints the way a modified IK will move. I’m assuming this is the case.
I suppose some rigs get really complex and the angle of some bones within an IK chain might want to be modified but to have constraints on them reduces how they can be modifed within an IK chain without affecting the constraints an IK chain has on the modified bone because IK ignores individual bone angle constraints. (IK doesn’t ignore other constraints)
Other then that, I’m not sure. It’s certainly a good question and this is my stab in the dark assumption haha
I thought one was for still animation. Moving each individual part. Where IK was for full on animation. I guess I was way off.
Well, I guess that could be one functional difference as well. I made a rig recently and it uses IK chains on the legs and wing bones and on the neck. I think IK chains save time and when used with a free bone which determines the plane in which the IK chain moves, can give a really natural movement of a limb.
I’ve taken some screenies of a baby griffon I made and rigged to give an example.
So the image shows an IK chain in (my interpretation of) a baby lion cub leg.
This shows the IK chain moving together. The bone I use to move this, is an independent “IK Target”.
Not all all bones are included in the IK chain because I wanted to have independent control of the “toes”. I don’t know what you call that part of a paw lol
Also something that is really useful is something called a “pole target” which again is an independent bone which is usually a child of the IK target bone (so that is moves with the IK target bone).
This bone you can see below which is selected.
Now when I move this bone, it will change the “plane” in which the IK chain of bones moves or faces.
So that’s really useful in keeping the IK chain in line with itself.
So some bones are not needed in an IK chain and some serve best to be in an IK chain because generally they naturally move together and it saves time to set up an IK chain when it comes to animating your mesh.
I hope that sort of explains it. And sorry for the massive images
Images are fine as well as the explanation. Thank you for taking time to explain it.
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