From the responses above it seems that UML is very much alive and well in certain parts of the games industry. I've been a professional software developer for many years across a few companies outside the games industry and haven't touched or encountered UML at all since i left university 14 years ago.
Same here... the only UML documents I see in our company is to make the technical documentation look more "technical".
There is crap in it like a diagram how much of the code is thirdparty vs generated vs self written code, percentual distribution. I mean, it is useful to know that most of a front end code is actually generated with jaxb, but creating a chart out of it and filling most of a documentation page with it sounds like epic padding.
UML Diagrams usually are more useful, but used very sparingly. Mostly as a high level view to quickly communicate the general architecture of a software component to a developer new to the project.
But then most of the time I worked on small projects. And outside of the game industry. So I don't know how much my expierience is worth. For what it is worth though, My expierience was that UML is something you will use in University projects a lot to make them look more professional (and help the people that have to rate your work understand it quicker). And that you will then not use anymore as soon as you start working professionally until you have to write technical documentation (which usually happens as you change jobs and will have to bring a new engineer up to speed, or outsource a component)... or if you happen to be lucky enough to work on a project that is NOT just glorified copy-pasta (like many projects sadly are, at least from what I have seen), you might use it for its originally intended purpose, to DESIGN a system, instead of just DOCUMENTING one. Which might also happen if you end up as an architect (Which does mostly Project management it seems, at least where I work, and less system architecture).
Judging from my expierience with external vendors, UML is also used quite effectively when selling your hacked together mish mash of different opensource frameworks as the best and fastest product for <insert current fad in the IT world here>...
When the non-technical customers start to ask too many questions, answer them with a mixture of half truths, blatant lies and UML diagrams. It might look like old egyptian hyroglyphs to the sourcing reps and managers present, but it looks technical so the sales rep of the vendor must know what he is talking about, right?
Okay, I might have a VERY biased view on the last use of UML, so disregard it if you are programming software as an external vendor and DO create well written, well documented software that is NOT just trying to cash in on a fad by selling it to people without the necessary knowledge