system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How distribution of film profits work.

Both box office and dvd sales. Do crews generally get a percentage or a flat rate etc.
gpt
It totally depends on the movie and the studio... its a bit like asking how does a company pay its staff, depends on the company.

If you are talking about a big budget Hollywood production then most of the crew will be on similar terms to any other job - they will either be paid per hour like temp staff or they will be on a standard contract with a set pay. They may be incentivised with bonuses, for example if they finish the effects on a scene within 3 weeks rather than 4 they get an extra 10% or something, but they will not generally be linked to the movies profits. There may be some kind of deal in place where if the movie makes a pre-defined amount, the staff bonus will be based on this much in the same way as how a company may pay a 10% bonus if profits beat target or something.  However, the real sharing of profits where the big bucks are made tends to be reserved for the stars and the senior managment involved in the production.

If you are talking about a smaller budget movie, then it may be the case that the crew are not on standard contracts or are paid at a reduced rate but are incentivised to work on a profit share deal - this will be put in place because the production cannot get the full funding so uses this as a way to cut upfront costs. However, in a big Hollywood blockbuster, this would be very rare for most normal people involved in the production.

Generally speaking, funding will only be given for a Hollywood blockbuster if the studio is fairly sure they are going to make a good profit - therefore they generally wont want to share much of that profit with deals where they have to give lowly crew members a slice of the pie for many years to come. They figure its cheaper and more effective to pay the crew like any other job - a standard contract with performance related bonuses which will be based on your own performance and the performance of the movie and / or production company, the same as most other jobs.

As a side note, Hollywood is notorious for shitting on people with temporary contracts paying crappy low wages - there is so much demand for the low level work that they can get away with treating people like shit.