Remove module limited by # frames after

so i was having a frustrating issue with the remove module behaving in a baffling manner and although i found a solution/workaround (which isn’t ideal but works to a degree) i wanted to share the problem and hopefully get some insight at to the problem.

i have a very simple setup. there’s a locked shot which has two swinging ropes which were part of a rig that i need to remove from the shot. i rotoscoped each rope separately then tracked (though it didn’t move at all) the background and then linked that track to the area behind the ropes that i wanted it to fill from. a very simple removal. but when i setup everything and began to track backwards from the end, after a handful of frames one of the two ropes popped back in, and refused to be removed even though the other one worked fine. what i ended up discovering was that the rope was reappearing after exactly 12 frames, which was the “# Frames After” that i had set for it. i experimented and increased this number to 15 and it removed it for exactly 3 more frames then stopped removing it, thus confirming my suspicion.

while this lets me remove it, it doesn’t let me do so unless by frame one, i’m sampling the entire 145 frame sequence, and this isn’t a great solution since there is smoke and debris obscuring the shot for a handful of frames near the beginning which dissipates over the shot so i wanted to limit the frames after, at least around that point near the beginning so that it wasn’t filling in with clear frames but occluded ones from just a frame or two away. beyond the inconvenience though, i’m just totally confused as to why the other rope was totally unaffected by this issue, and behaved exactly as i would have expected. they were set up with identical parameters including the 12 frames after, the only difference being it was above the other rope in the stack if that could have something else to do with it.

the order being:

right rope (worked normally)
left rope (rope limited by # frames after)
background (linked to track below)
background track

i’m hoping i might get a solution that will let me use all the features of the remove module as intended, but if nothing else i’m hoping maybe for some sort of explanation or idea as to why this happened. it’s the inexplicable nature of it all that bugs me most.

Hi there,

Use the amount of frames before and the amount of frames after at the number of frames in the shot, if you need to conserve memory, just increase the step.

And make sure the frame range if for the correct range.