I just made an animation that has the background overlapping objects in a way that doesn't in viewport of if I render the frames individually. I normally don't use forums and figure things out on my own, but I'm stumped...you can see it for yourself in my latest animation https://cgcookie.com/u/misteranimation/projects/robot-on-bus-with-noise
specifcally, the buildings in the background move, but sometimes a copy of them overlaps and stays still
It's hard to know for sure without digging into your .blend file. My first inclination is to check the modifiers of the offending objects. Since modifiers can be on or off independently from viewport to render, chances are something is on / off in the viewport while being the opposite for rendering.
Likewise the outliner also has relative states of renderability. Check if some objects are on / off in the viewport while being the opposite for rendering.
If neither of those directions solves your issue, feel free to upload your .blend file to dropbox, google drive, or equivalent service and post a download link here so I can take a closer look.
https://drive.google.com/file/d/1O6Q93nIXJmnlQMnAXmQtiqFWEfe9aNsi/view?usp=sharing
Also, There are linked files, so please use the BGtest.blend file
I don't think anything you said would apply in regards to the differences of a render (frame) to a render (animation)
but feel free to try them both. with this cut down file of just the background (which I just tested and can reproduce the issue on two different computers with different setups and blender versions).
Thanks for supplying project files. I'm getting a string of missing library files though:
This makes me wonder if the error has to do with library linking. And honestly I'm still not sure about the issue itself. I don't really see the duplicated static buildings in the scenes you provided or in the video you rendered..I thought it would be obvious in the scene files.
If you can point it out in the video with comparison stills from viewport render vs animation render that'd be helpful.
ok. I rendered it and made a video for you
This is what you see if you render animation from the file I uploaded. Also, the orphan data is just because I deleted hierarchies of the other elements in the scene to reduce the size of the files. It doesn't affect the issue in rendering
I've been trying things out, but can't figure out what's wrong.
There are a lot of problems with dependency cycles(53 in total), though. Don't know if that has anything to do with it...
bke? did I bake something by accident? and would that baked data carry over to my other computer in that small file I tested?
the cycle dependencies do act weird in the viewport and I need to go forward and back a frame to refresh it and make it look the way it's supposed to. But I still can't figure out this main thing: why does a render frame get it right, but render animation doesn't? I just wish render animation was the same as render frame and simply act as automated batch work...
I think BKE stands for Blender Kernel.
Here are some test renders I made. Sorry for thew bad naming, but the top row was rendered in 2.81 and the bottom row in 2.83:
As you can see, not even the single frames are consistent; The two on top right are the same, after closing Blender and re-opening it.
?????
I don't remember having an issue with any single frame last month, and I rendered them individually almost a thousand times... now I have more questions about it from your results. This isn't good. My wife really doesn't want to see me spend more time on this, lol. I need to put a pin in it while I work on some character animations
I can only guess, that that has something to do with the dependency cycles.
If I render the animation and after that render a single frame, that gives a different result than when I re-open the file and then render that single frame (before 'playing' the animation).
(That would mean re-doing the whole rigging.)
But really, I don't know.
It's probably a good idea to let this rest and do some other stuff for a while.
Yikes misteranimation it looks like you've run into a crazy bug. I'm really sorry to see this derail a project you've clearly put a lot of time into. Consider posting this information into an official Blender bug report.
spikeyxxx Once again I can't thank you enough for troubleshooting fellow peer issues. We're tremendously grateful! 🙇♂️