What is render files?

I`m sorry for all my questions, but I promise, this will be me last topic for a while!

What is render files?
I know I can delete some of them to clear some hard drive space. And FCPX makes new when I start up project again.
But what is render files?

Cheers!

When you apply an effect or make a color correction or a transition of something like that, the video of that does not exists on your hard drive. The computer can usually process it in real time, but if you actually want to see it playback in full quality and you want to export it a piece of video has to be created that contains that effect or transition or color corrected video. That piece of video is a render file.

Think of things in the Timeline like Layers in Photoshop or Motion.

I have a clip in Storyline. That's one layer.
I place two filters on it. There's two more layers.
I put a PIP image on top of that. Another layer.
Titles on top of it all. I just ended up with 5 layers, so to speak.

When I playback, the computer has to stream all 5 video layers (plus each audio channel and filter add more layers), mix them, all in real time, which can be difficult. With music, narration, sound effect that adds 7+ more (audio) layers.

A render file is a way to "flatten" or "merge" all of that stuff so I'm only playing back one video stream, and two (stereo) audio streams. MUCH easier for the computer to play back, but NOT the final output, thus it only needs to be good enough quality for playback, not delivery. That adds more ease of playback for the computer. They only effect playback and nothing else, not export, nothing.

BenB wrote: Think of things in the Timeline like Layers in Photoshop or Motion.

I have a clip in Storyline. That's one layer.
I place two filters on it. There's two more layers.
I put a PIP image on top of that. Another layer.
Titles on top of it all. I just ended up with 5 layers, so to speak.

When I playback, the computer has to stream all 5 video layers (plus each audio channel and filter add more layers), mix them, all in real time, which can be difficult. With music, narration, sound effect that adds 7+ more (audio) layers.

A render file is a way to "flatten" or "merge" all of that stuff so I'm only playing back one video stream, and two (stereo) audio streams. MUCH easier for the computer to play back, but NOT the final output, thus it only needs to be good enough quality for playback, not delivery. That adds more ease of playback for the computer. They only effect playback and nothing else, not export, nothing.

Great, simple explanation! I like the "flatten" or "merge" concept as you applied it here.

Dave