After Effects skipping animations in preview and render

Report · Feb 02, 2020

Hello, I have a 1 second clip in after effects. I'm animating hand drawn wind lines behind a motorcycle. The clip is 60 fps, and I drew the animations on every other frame. The effects used are just paint and glow. I tried deleting glow, no help. Preview skip is set to 0. Paint on transparent checked, and I'm painting on a copy that is above the original clip. I've also cleared the cache and tried playback with cuda disabled.

The problem- the animations are skipping and sometimes disappearing all together. If I let preview play on repeat, sometimes they're all or mostly there, sometimes there are a notible chunk of animation frames missing, and sometimes the motorcycle drives by with no animations playing at all. If I stop playback and navigate frame by frame, every animation is still present.

I rendered my Premiere project that has this clip attached(dynamic link), into an h264 youtube 1080p file. The weirdest thing is that playback through both Pot player and VLC the same exact thing happens. The first time no animation showed at all. Then I played through it again and there it was. Then again but with portions of the animations missing... how does that even happen on a rendered video? lol Not sure what to do next.

Report · Feb 02, 2020

A couple of thoughts...

How thin are these lines? Are they so thin that if the video is viewed at a smaller size on screen they are "averaged" out?
You said you cleared the cache but did you do this?
Edit > Purge > All Memory & Disk Cache...

Report · Feb 02, 2020

Thanks for the reply,

yes, I followed that path and selection for cleaning the cache. The lines are actually quite thick but I did first outline them with the #5 circle brush and then filled them in with a thicker brush as I was wanting a certain look. Is it bad to fill in with brush strokes? I actually did another two second clip before this one and it worked fine(I would have cried if that one didnt work lol)... but i dunno.

Whats so strange to me though is that the rendered video file sometimes plays with the lines and without. If the frames are painted on, where is it getting the clean frames?? lol

Report · Feb 02, 2020

In your original post you mentioned that you are drawing on every other frame. Does that mean every second frame has no drawing on it? Have you tried drawing on every frame or ensuring that what you do draw exists for as many frames as required to get to the next frame with drawing on it? ie. Extend every drawing to occupy two frames instead of one frame.

You also mentioned in your original post that you are working at 60fps. How are you rendering out? If you are rendering out to something like 30fps, could After Effects be only rendering out every second frame. This could explain why sometimes you get the lines yet other times you do not.

Report · Feb 03, 2020

Rendering the final file out in 60fps, so it shouldnt be that. Yes every other frame is blank. I might have to give that a shot to see if it works. Thanks for the help.

Report · Feb 03, 2020

Cheers.

One thing thing that might help is to explore the Duration option within the Paint panel. This setting allows you to set how many frames are occupied by whatever you draw. In my example I have set it to Custom and then changed that number from 1 to 2. Now whatever I draw occupies two frames by default.

It's also possible to change the duration of a brush stroke after the fact. Within the Timeline panel open up the Paint effect and find the individual Brush strokes. Their duration within the Timeline can be manually lengthened or shortened.

Report · Jun 25, 2023

Hi,

also check if you are using a stroke path that the 'Spacing' is set to zero otherwise it will skip frames and not be a smooth trace. best,

Sam