I have been working on a multiclip project for several months without any performance issues in fcpx. I locked edits a month ago and set fcpx to use original clips. I have been working for a month without a problem. 2 nights ago, I shared (rendered) my project for iPhone and it was set to set to iTunes library. I came back 3 hours later and it was only at 7%. unfortunaltely, I had to force quite fcpx. Well, now, that project takes 4-5 hours to open.
My first thought was corrupted render file(s). fcpx has the "Delete Project Render Files" option. What exactly are the render files its talking about? are these the same as the proxy and optimized? If I choose this option, what will the impact be within my project? will it automatically rebuild them when I open the project?
I thanks in advance for your time and help on resolving this issue.
No, they are NOT the same as proxy or optimized.
When you add a clip to your timeline and, say, apply an effect to it, or superimpose a title on the clip, FCP X has to make many calculations to determine what color each pixel of each frame should be. If a section of your timeline is not rendered, it has to do all these calculations every time you play those frames. A render file has the frames already "calculated", so it plays fast and smoothly.
For simple compositions and a fast computer, you may avoid rendering completely - and you may also choose to only render the portions where playback stutters.
Render files can be safely deleted. FCP X can recreate them if needed (either automatically if you have "background render" on, or on demand, when you select the "render" or "render all" commands).
this is great information, thank you. However, I have the project open and the "Delete Project Render Files" option is greyed out (unslelectable).
The command is active when you have the project library open, not the timeline.
Open the project library, by clicking the button at the bottom left of the window, below the timeline.
Make sure that your project is selected in the project library.