A short, thoughtful, detailed rant:
Whilst researching for a games project I'm currently working on, it came to my attention (at the time of writing) that there isn't an enormous free body of work online the delves into some of the more niche techniques that are so abundant in AAA game design, especially when it comes to environment art. In my searches, phrases like 'Trim sheets' and 'Vertex Painting' come up a lot but when googled, the guides on how these things are built an implemented are few and far between.
Which isn't to say they're not addressed at all, in fact, some of the material that's recently come out on the subject by the likes of Tim Simpson has been incredibly useful, it's just surprising to me that fundamentals such as the aforementioned Trim Sheet are only just beginning to crop up in the world of free online tutorials. My friend, the very talented Lorinn McCaul and I were talking about how to get efficient resolution quality out of larger in-game assets without breaking your texture budget and we realised suddenly how much of a gap in our knowledge there was.
If your not in the know, here's the little I do know about the topic: Essentially, due to the real-time nature of games, performance has a huge weigh in on what does and doesn't make it into the final release. Whilst games have been getting steadily better and down right beautiful in most AAA cases, it's still very expensive for an engine such as Unreal to pull in multiple texture sets, especially once those texture sets start cranking up above 2k resolution. An average character used to be made up of two UV sets, the head and the body (depending on it's role in the game of course) which in and of itself is usually at least three roll-calls assuming that you package your materials into RGB channels. Imagine then the texture of your average house, well one wall by this logic would be so many uv's that to build a simple scene in a larger game would be too expensive.
To get around this, developers employ a host of techniques such as tillable textures mapped to the world space so that they can seamlessly connect to other modular assets under a single texture set. To add detail, they create trim sheets - single UV sets of normal maps that can be laid out over multiple other objects to add detail such as bevelled edges, pipes, bolts, etchings, runes and so on.
This would have been very useful to know when I was working on that project but you live and you learn, and pushing ahead with the conception phase of an environment in the near future, I will definitely bare these techniques in mind!
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