In the 3D-view you'll see a yellow line from the IK solver to the root of the chain it covers. For example like a doll: if you pull one hand, all the body will follow. This concept of multiple IK targets in a rig is called Tree IK and can be used to get completely automated animations. If there is another IK target in other sub-branchs of the rig, Blender will try to mix them. If all the bones are linked up to a master root, then all other sub-branchs will be affected. Also If you set len to 0 and your chain's root is a child of another bone, The IK solver will reach and rotate all the bones until it gets to the end of the parent relationship.If for example the len is 4, only the 4 last bones of the chain will try to touch the target. If set to 0, the entire chain will enter in the constraint. Len lets you tell Blender the length of the chain the IK solver will try to rotate.It's interesting to use tip, because this way the Bone holding the IK constraint can be used to deform geometry. The Tip button lets you tell Blender which part of the bone is the target, the Tip or the Root.The Rot button let you tell Blender to use the rotation of the target to influence the rest of the chain:.You can select which Object or bone will be the target.Q: ' CTRL-IKEY' doesn't seem to do anythingĪ: Either the 3D Window is out of focus (R-click in empty space to solve) or you're not in Pose Mode (' CTRL-TAB', selected bone will be magenta in color)Ī: In the 2.48 version of Blender, the shortcut is ' SHIFT-I' The Constraint Panel It's also possible to remove all IK constraints from selected objects or bones with ' ALT-IKEY'. If the target would itself be part of the IK chain, you get an error message - so make sure the target bone is not connected to the bone you want to add the constraint to. The menu will then let you add a constraint to the current bone with a target. With this way of selecting ensure that your target is selected, but the bone you want to apply the constraint to is active (the last one selected). You can also select the target and then the IK constraint holder and press CTRL-IKEY. Though you have less freedom (no rot feature, difficult parent relationship). It's now possible to work without target. If you select a bone and press ' CTRL-IKEY', You get a little menu asking for more info on the new constraint, the target: to a new empty object or without target.
The IK solver has a special shortcut in Posemode to be added easily to a bone. Now this Constraint got most of the attention during Animation refactoring, hopefully we have a lot of toys to play with now. All bones in the chain are trying to rotate to keep both ends on targets.
It takes longer, but gives you entire control over the rig. You have to animate the bones rotation one by one to get it animated. In Blender, a FK chain is a chain of bones connected together.