Deleting Flow Files, next....

If I come back to the project after deleting the flow files, (Optical Flow slow motion) will the footage play smoothly or do I need to recreate the Optical flow over again? Thanks.

Once optical flow files are manually deleted, they need to re-render again in your timeline to provide any benefit to the clip they are applied to. Generally this happens automatically as long as the video quality remains set to "Optical Flow". This is usually related to re-timed clips. As far as playing smoothly, optimized media (not Optical Flow) is what allows footage to playback smoothly on less powerful systems. Optical flow improves the quality on re-timed clips but may not necessarily cause that clip to play back smoother than it otherwise would (although it sometimes appears that it does visually).

Thank you dgw! All my media are optimized. But many times when I set slow motion to 50% or 75% the slow motion looks jerky. So Optical flow or frame blending improves the picture.