Is it possible to insert a keyframe without affecting the slope of the existing curve?
I want to do this because I’m animating some walk cycles etc to be used in Unity. Unity animations go from the action’s first keyframe to the last, so a clean animation loop must begin and end with a keyframe for all curves.
But what if the animation requires a smooth motion to occur across the loop? I can’t key a curve to go from the third last frame to the third frame because the loop needs to begin and terminate with a keyframe. I can throw a keyframe midway through the curve, but this affects the slope of the f-curve.
So again, I ask, is it possible to insert a keyframe without affecting the slope of the existing curve?
It looks like there is always a jump that occurs.
You can CTRL-Click on the curve and this will place a point on the curve. Then just adjust the tangent handles to reshape the curve.
use the bezier handles to adjust the curve back to its original slope and curvature (or at least very close)
Dupe the new adjusted key to the last frame of the loop. The new key will be identical to the original in terms of bezier handle orientation, so as long as the keys preceding and following the loop start and end frames are identical, the new terminated loop should work just fine.
Adjusting the handles to recover the curve can be a bit tricky with some animations, but in general isn’t that difficult.
I’m not in front of blender right now, but I think that if you go on the frame you want to add you keyframe and on the transform info you add a keyframe manually, I think blender will try to insert it without changing the curve. But since I’m not in front of blender right now, I cannot test my theory!