I’ve searched the forums for how to keyframe an object’s location constraint to another object. Theeth suggested to look for Slikdigit’s constraint trick in the Q&A but couldn’t find that either.
I have a simple armature setup. The IK solvers for the arms are Empties named wrist.R and wrist.L. These Empties are parented to the character’s Master Empty. I have inserted Loc keyframes for both wrists. When I rotate the Master Empty, the wrists move with their parent.
I want to halt the movement of one of the wrists with a location constraint but can’t figure out how to affect the constraint’s influence. I have read that in the IPO window there will be an INF (influence) channel and to Ctrl+Lmouse click to add a keyframe. I inserted a keyframe for all available channels for my wrist but I don’t see an INF channel.
Here’s the wrist moving freely…
Here’s where I want the wrist to be constrained…
But now, the wrist moves past the Empty that I want the wrist to be constrained…
Insert a location ipo for the default plane
advance frame counter to say 21
Move the plane to the right a few grid spacings and insert a second location ipo
Add a default empty, somewhere above and between where you moved the plane (not important)
re-select the plane, and return to frame 1.
Bring up the EditButton window [F7],
In the Constraint panel, add a ‘Copy Location’ constraint and enter ‘Empty’ after the tab ‘Ob:’
Open up another window - change it to an Ipo Curve window, and then in the little selector box in the window header (which should be displaying ‘Object’ now) change it to ‘Constraint’,
In the Edit Buttons window, click on the little ‘Edit Ipo’ button, (In most cases, you will most likely have more than one constraint…)
In the Ipo Curve Window, click on the 'Inf’luence tag in the right hand column (It should turn white to indicate it is selected)
Finally, in the Ipo curve window, Ctrl_Left mouse click at frame 1 to estabish an influence value of 1, and again at frame 21 for a value of 0. (The values are not important, just a simple example)
Ever since they’ve changed the GUI, things look cleaner but there are things that I keep missing. It makes sense that the Influence IPO for the constraint would be under IPO Type -> Constraint.
Since I was under a deadline, I just keyframed the wrist every frame I needed it to be “frozen.” Not the most elegant solution but hey, it worked.
