I’m working on a typographic animation that’s around 2 minutes long - it’s rendered with Cycles.
When I render it out some parts of the animation contain some weird black rectangles or are completely blacked out and I can’t figure out why. There are no objects obscuring the view - viewport preview Cycles render doesn’t show the artifacts, they only appear on the final render.
I am using some objects with “holdout” material to separate different “scenes” of the animation or other objects that are pure black for special effects, but - they would show up on the wireframe. I also animate the camera visibility of those objects or their scale (scaling from 0 to 1 and back to 0) so they don’t show up in those parts of the animation where they are not needed and could cause trouble. Once again - it that was a problem the problematic geometry should be visible in the viewport - but it isn’t. In some cases I can see some relation to the exising geometry - for example int hte poctures below the black region stops where a holdout plane starts in the view. This seems like some geometry processing errors - but as you can see the viewport Cycles render is fine!
Take a look:
https://youtu.be/D3GcyVX1YaA - normal animation render
https://youtu.be/fn8_xHDG8ns - with wireframe overlay
https://youtu.be/ErL30EzYh7s - with wireframe slowed down 4 times
Download the project file: