Is there a way to move an IPO key along one axis only? ie, to constrain it whilst moving it.
I often want to adjust a key’s value (vertical) without affecting it’s position in time (horizontal). I’d like to constrain a key to the Y axis for example, and just slide it up or down without worrying about inadvertently modifying the timing of the keys.
Is there a way to do this?
Perhaps the quickest - and most accurate - way is to select the control point(s), hit N-key and enter a Y value.
Works just like transforms in the 3d window :
or
MIke
g x. and hold down control while mousing to get even frames.
mmb works, but g then x/y doesn’t do anything. am I missing something? it just free transforms as usual 
GX and GY (aka axis-locking) is only available in the Blender 2.43-RC1 and CVS builds.
Aligorith
Oh ok, good to know. Thanks!
I’m sorry, I was wrong - i misread your post. For the current version and many versions back, get out of key mode and into Curve mode by pressing C in the IPO window. RMB select the curve you want or select the curve from the list on the left side, ie Loc X or Rot Z, whichever you want to increase, and press Tab to go into edit mode. RMB the dot you want, and N for traNsform properties. type in the Y value you want. If you Grab, hold Control down and unless you’re spastic, you should be able to keep dX at 0.
For the current version and many versions back, get out of key mode and into Curve mode by pressing C in the IPO window.
That’s “press K in the IPO window” Roger (having a bad day? ;)). C doesn’t seem to have any effect here which is odd since I would have expected it to centre on current frame - as it does in Timeline and Action Windows.
Holding CTRL seems to limit vertical movement to increments which makes it easy to move along X without changing Y but not so easy to finely adjust a Y value - or limit movement in X while adjusting Y.
(2.42a and earlier)