ELI5 What is rendering in CGI

I might be corrected, but from what I’ve seen, rendering is compressing imagery into a simplified version. Creating CGI takes a lot of layers, light sources, details, what have you, in the current program the artist is using. Not rendering these A LOT of processing power, rendering compresses those parts into a video that’s easily viewed and moved around. I’m a graphic designer, and I suspect it’s the same with programs like photoshop, where saving and moving a file as a .psd takes more processing power than exporting it into, say a .jpg, where all the layers are compressed into one image rather than it having to remember every single layer every single time.

/r/explainlikeimfive Thread