Hi, so Material ID should be very useful for postproduction, but sadly it’s not. we normally have a lot of objects in the scene and selecting color in photoshop is not that useful.
what’s useful is the sky mask. you can Copy it, press Q and then paste it then press Q again and it’s selected! it doesn’t have “Selecting by color” part. we need this. how can we do it?
one is material ID based on layers. for example, I put all my characters in “characters” layer and choose this layer on channels. then you give me black and white mask, including all my characters. this way, they’re usually apart from each other, so I can easily select them. and if they were not apart, I can go with different layers.
another is based on type. Like Vegetation, cars, etc.
lastly, we can simply choose material. easiest option.
thank you.