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Sliding linear keyframes in Graph Editor
Hi:
I’ll start up front by saying that I am not a fan of the Graph Editor that was foisted on me in AE7 and later. I stuck with AE 6.5 for over a year until I had to upgrade to AE CS3 when we got our Intel Mac Pro earlier this year. I was quite happy with the old twirl down speed graph, and I wish Adobe would have retained that functionality in addition to the Graph Editor (for those who like it.)
That said, now that I’m stuck with the Graph Editor I have a usage question. Let’s say I have a layer moving left to right across the screen, with a linear keyframe at the starting position and a linear keyframe at the ending position. I want that layer to travel at 60 pixels/second.
In the pre-AE7 days I could twirl down the position property to display the speed graph, select the ending keyframe in the timeline and drag it left or right until the numerical speed display showed the layer was traveling at 60 pixels/sec. Pretty simple and straightforward.
Now I’ll try the same thing in AE CS3. I have my layer moving left to right with linear keyframes at the beginning and end of the move. I select the position property and open the speed graph. I select the ending keyframe and drag it left or right, monitoring the speed in the Info palette (which is on a totally different monitor by the way, forcing me to look back and forth between the Graph Editor and the Info palette. Yes, there is a grid in the Graph Editor which roughly shows the speed, but it’s pretty coarse.) Unfortunately, my ending keyframe, which started with a linear temporal and spatial interpolation, changes to a Current Setting temporal interpolation, and my nice flat constant speed line changes to a curve, with the previously linear speed now ramping up or down depending on whether I slide the keyframe forward or backwards in time.
Why do my linear keyframes inherit influence handles in the Graph Editor? The closest I can get this to work like it did in AE 6.5 is to select the influence handle on the ending keyframe and drag it over to the keyframe to 0.01%. Then I can select that keyframe and drag it left or right in time to get my flat 60 pixels/sec movement. That adds an additional step, and my previously diamond-shaped linear keyframe now has a bezier-in shape.
Is there a way to turn off the influence handle for linear keyframes in the Graph Editor so they stay linear when sliding them in time? I’ve been studying the Graph Editor in the manual and I don’t see this issue addressed.
Any thoughts or suggestions?
Thanks.
Shawn Marshall
Marshall Arts Motion Graphics -
2 Replies
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If you want a completely flat speed between two keyframes, the best way to keep it flat is to select both keyframes in the Graph view, then slide only one of them in time. This way, the speed remains constant and won’t introduce any curves.
However, to the broader question: I’m not sure if you can completely eliminate the influence handles. But the method I described earlier should keep them from switching to “Current Settings.”
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Hi Paul:
Excellent! That seems to do the trick. Thanks for taking the time to reply and thanks for the tip.
Shawn Marshall
Marshall Arts Motion Graphics
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