@FrankPolygon this is gold, thank you! I've thought about it more since the first two answers, and indeed I came at the conclusion that it didn't make sense. If normals couldn't be rotated then they would be world space normals, which are an entirely different thing, and it would mean that any object with a normal map…
I find myself stuck with a mistery that is making me loose hours of work without any progress whatsoever figuring it out.I'm making a modular environment and I'm making some trimsheet textures. In this specific case let's take a door frame made of three pieces (two vertical, one horizontal on top. Everyting is cool and…