5 Replies Latest reply on Mar 31, 2016 7:20 AM by jkustan1

    Odd spike in position graph when using Ease ease?

    jkustan1 Level 1

      Hello everyone -

       

      I've run into this problem recently and can't seem to find a solution (TBH not sure exactly how to search for it either).

       

      When creating two position keyframes for a layer, even when the thing is moving in a straight line with no other keyframes, I keep getting this weird effect where the layer sort of "wanders" off course before getting to its final destination.  When I open the graph editor the curve for position looks like this:

       

      Screen Shot 2016-03-29 at 3.04.15 PM.png

      I want a smooth curve between those two keyframes, or even a straight line, but instead Im getting that odd spike.  This keeps happening and I cannot find an consistent reason and its driving me nuts

       

      Thank you for your help!

        • 1. Re: Odd spike in position graph when using Ease ease?
          jkustan1 Level 1

          I'm replying to my own question to say that I think I found a solution, but it still does not explain some of the behavior I've noticed: FAQ: Why does my layer (camera) move back and forth between keyframes of equal value?

           

          I've toggled on the "Default Spatial Interpolation To Linear" and so far no new keyframes have exhibited the strange behavior.  However....

           

          Right clicking on the keyframe and changing the individual settings in the "Keyframe Interpolation" menu does not seem to fix the problem.  It looks to me like some sort of interpolation is/was being automatically applied, and consistently showed that same spiked curve.  If anyone has any further ideas/comments I would appreciate it Thank you!

          • 2. Re: Odd spike in position graph when using Ease ease?
            Dave LaRonde Level 6

            You need to familiarize yourself with the drift-eliminating properties of Hold Keyframes.  They can save you a lot of problems, and it's easy to learn how to use them.

            • 3. Re: Odd spike in position graph when using Ease ease?
              jkustan1 Level 1

              Hi Dave, thanks for the response!

               

              I'm not sure that hold keyframes solves my issue (which is unfortunately not solved as I previously thought), but I may be misunderstanding you.  Converting my keyframes to hold keyframes converts them from

               

              Screen Shot 2016-03-30 at 9.13.45 AM.png

               

              to

               

              Screen Shot 2016-03-30 at 9.14.05 AM.png

               

              Which is not what I'm looking for.  What Im looking for is a steady slope, like this (I had to manually open the Keyframe Interpolation menu again to get this):

               

              Screen Shot 2016-03-30 at 9.21.15 AM.png

               

              I still can't figure out why I'm not getting that steady linear slope to begin with, since I figured I had solved it by changing Default Spacial Interpolation to Linear, but it looks like the problem persists.

              • 4. Re: Odd spike in position graph when using Ease ease?
                Rick Gerard Adobe Community Professional & MVP

                The default spatial interpretation gives energy to movement. Sometimes when you set or move keyframes there is a little carryover and you get a little pingpong or unexpected motion because of the energy in the movement when the position is changed by a keyframe. If you zoom way in and look at the path you can see overlapping bezier handles on the path. This problem is extremely difficult to fix in the graph editor by dragging values around. When you set the default spatial interpretation to linear this energy with all it's vectors is removed so you get straight lines between the points. This may work fine for your animations but most of the stuff that I design works better with energy and curves.

                 

                If you have a problem like this example and you need to maintain a curve and want smooth motion it is usually easier to start in the Composition Panel by examining the path and use the pen tool (g) and modifier keys Alt/Op;ion and Cmnd/Ctrl to adjust the curve. Take this example:

                Screen Shot 2016-03-30 at 7.01.13 AM.png

                Correcting with the pen tool gives me this:

                Screen Shot 2016-03-30 at 7.09.57 AM.png

                The other option is to adjust Keyframe Velocity and/or Keyframe Interpolation to smooth out the path and the motion.

                Screen Shot 2016-03-30 at 7.15.20 AM.png

                In most cases, if you want a smooth path, then it's best to start with the pen tool in the Composition Panel and then work on the timing. Then you can fine tune things with the Keyframe tools. If you need do some polish using the graph editor it is usually a good idea to have the Reference graph (speed in this example) visible and choose Edit Position for position and Edit Speed for timing.

                Screen Shot 2016-03-30 at 7.20.18 AM.png

                Because of the energy put into motion along a curved path editing the speed or value graph can get really confusing. That's why I usually start in the Comp Panel.

                • 5. Re: Odd spike in position graph when using Ease ease?
                  jkustan1 Level 1

                  Thank you Rick for your time and the tips, seems like this is a known issue so I'll try editing the path directly in the future! Its true that the linear motion seems less desirable in a lot of places (very jarring) ... The project Im working on has a lot more moving parts than I've ever worked with before, so its a learning experience for sure.

                   

                  Thanks again!