“Without going into mind-numbing and proprietary detail, I’ll give you a rough sketch. Our basic file hierarchy grew out of our commercial production environment which was, in turn, greatly influenced by ILM‘s shot naming convention and the Unix operating system.
ILM named the shots with a two-letter prefix and a number. SB_19 was Space Battle 19 (a monster of a shot in Star Wars: Episode VI – Return of the Jedi (1983 movie) which may still hold the record for the greatest number of optically-composited elements). So we sort of borrowed that idea, but gradually grew from two to three and then an arbitrary number of letters before the underbar.
So a hierarchy was set up under a “prod” (for production) directory for each commercial. Under it were trees for models, animation, textures, final renders, etc. That rough idea survives, but now we have a lot of fancy software keeping track of where the assets actually live. The important thing is for the right artist to be able to find the right assets.
When we started Toy Story (1995 movie) we just figured that each sequence was kind of like a commercial, so we just moved that whole “prod” notion below one more level, called a “unit”. We still work that way. The shot names have converged on a letter-number_number convention. So Toy Story 3 (2010 movie) was unit “ts3, Finding Nemo (2003 movie) was unit “Nemo”, etc. In unit “brave” all sequences begin with the letter “b”. Shot b100_23 would identify itself as part of prod (ie: sequence) b100, and be shot 23. When we do alts or otherwise add shots we start appending letters, as in b100_23a, b100_23b, etc.
Of course, very soon after production starts the shots are no longer in any kind of logical order, so a production database has to keep track of the show order (and a gazillion other details).
On top of all of this organization is an asset management system (currently PerForce) to keep track of revisions and control whose turn it is to mangle an asset. As you no doubt suspected, it’s a big deal, and not a trivial problem to solve. As is often the case, decisions made in haste decades ago are still with us.”