the FCPeffects blog: Final Cut Pro X tips & tricks
Final Cut Pro X uses a lot of hard drive space storing render files. To recover some of this hard drive space, it's important to delete these files from time to time (especially for projects you're not currently working on).
Deleting these files will not harm your project(s). Final Cut Pro X will just have to recreate these files the next time you open the project...
Knowing keyboard shortcuts for FCP X can save you a lot of time....

Optical flow works by creating frames in between the actual frames of your footage. Instead of repeating frames or blending them together, FCPX creates new frames based on the content of your footage, thus making playback smooth...
