- You can key the influence of any constraint, IK solver included . There are some issues apparently with switching between zero (no influence therefore FK) and 1.0 (full IK) for some people … though if you key the driver object properly in the animation I have found it works well enough …
But here is how you set up a IK influence slider :
A) Split up an area and turn that into a IPO curve editor window (if you didn’t have one open yet) and switch the ipo constraint type to “Constraint” (hit the up/down arrow next to the “drowning man” icon and the ipo types available will show)
B) Now go to the IK solver panel you want to key the influence of and hit “Key” . The only available curve for constraints (Inf) will show up blue as a horizontal line .
C) Now go to the IPO curve editor window and while holding down the Ctrl key click with the LMB to add a new point on the curve somewhere close to zero along the Y axis .
D) Now hit N while in the ipo editor . The Transform Properties window will pop up and from there hit “Add Driver” . An “OB:” field will show up . Add a cube which will act as the driver into your scene . Now type the name of the cube into the “OB:” field . and a couple of dropdown fields will show up … there are various options for these but for now leave them as is . The Object field indicates that you are using an object type to drive the channel and Loc X indicates that the location of the driver object along the X axis determines the travel along the curve .
E) The final part of the set up just requires some editing of the Inf curve . Change the Interpolation Mode to Constant for the curve . Then tab into point edit mode and select the point closer to zero along the Y axis and manually input “Vertex X 2.00| Vertex Y 0.00” into the respective fields . This means that when you move the cube driver object 2 BUs along the X axis the IK constraint will have no influence and so effectively it is now a FK bone .
That’s it . Now when you move the cube 2 BUs along the X you will have FK … move it back and you will have IK back …
And finally here is a rig that already has that installed and made to look pretty : http://blenderartists.org/forum/showthread.php?t=106275
- Just parent it . Select the null (empty?) and then shift-select the head bone or whatever and Ctrl-P in Pose Mode . Now the null will move with the head bone .
Wow three years alone in the wilderness of Blender … Well welcome to Blender Artists ! I have been using Blender for about a year myself (started when I joined here) and having this forum has helped accelerate my learning Blender quite a bit . Trying to help out with questions/problems that users have is a great way of learning the program .