Motion Graphics - Actions are scrambled while scrubbing

Creating a motion graphics explainer video and having a problem with actions getting scrambled. You can recreate this in the attached blend file.

Animation (usually) plays fine first time.
Second time animation plays, objects are not initialized in proper place.
Scrubbing timeline will put objects in random places along keyed paths.

The animation can be reset if you go to the final frame, then use the left arrow to work backward to the beginning. Playback will work fine after that.

This sounds like a problem with the way I’m creating keyframes or organizing actions, but I can’t figure it out. Any help would be appreciated.

Thanks,
Scott

Attachments

ScrubProblem.blend (2.48 MB)

Okay, so no replies. How about I show you what the results of running the attached blend file.
FirstRunWorks.avi - First run through the animation all is fine
SecondRunBad.avi - Second run through, elements are not position correctly
ScrubTimelineRun.avi - After scrubbing forward and backward through timeline, object positions are even worse

Any ideas?

Thanks,
Scott

I have not been able to nail down the issue. I won’t have much time to look into it for a few days. Hopefully someone else can find the problem before then.

Sorry.

Edit: One quick guess. Go to frame 1 of your animation. Make sure you set a keyframe for the default location, rotation and scale (or any properties that you are using) for every item that you have an action for.

It’s the only guess I can give you at the moment.

Good luck!

Thanks, DanPro,

I already checked to be sure that there is an initial keyframe in the beginning of each Action. I don’t go to frame 1 of the entire timeline because this would make each action strip VERY long. I don’t think that is how Action strips are supposed to work anyway.

Thanks again for looking. Hopefully someone will figure it out.

Scott

It does not look like you are using the NLA Editor. That is where your action strips should be placed, rearranged and edited.

If it’s possible, could you make a simple file, stripped down to just a couple actions and objects and reproduce the issue? Maybe that would make it easier to figure out what is going on. Like most issues in blender, it’s often a simple fix once the real issue is narrowed down.

OK. Here is a bare bones blend file with a single object, Two actions. Scrub the timeline forward and backward. If you go SLOWLY everything works out. But if you scrub backward quickly, the actions are not interpreted fully and the animation doesn’t fully reverse.

Let me know if you cannot reproduce this problem or if you have any fixes or workarounds.

Thanks,
Scott
ScrubProblem2.blend (1.42 MB)

The only thing I can come up with for a solution is to change the Extrapolation Type in the NLA Editor. You have it set to Nothing. I changed it to Hold and all seams to be well for the latest example. This may not be what you are looking for, so change this in your main file for a few of your objects/actions to see if it’s the right solution.


I also noticed that your extremes have no keys. You reached those extremes by tweeking the handles. If this works for you, all is well. However, it makes using the Dopesheet nearly useless for editing actions as the extremes have no keyframes. They are only visible in the graph editor.

It a personal preference, but I would suggest adding a keyframe for all extremes in your actions, rather then relying on the position of the keyframe handles.


Good luck!

Changing the extrapolation has done the trick! I’ve gone through and made the changes for several problem areas and they all have been fixed. Thank you for your help!

Scott