HORRIBLE IDEA. ABSOLUTLY HORRIBLE!
If you do that, yes, your map compiles quickly, but you know what else happens? Your r_speeds goes through the roof, and your framerate through the floor!
Making everything a detail brush but those which enclose the level is forcing JO to render every part of the entire level at once. It won't know how to block parts of the level that shouldn't be drawn.
Structural brushes should be the main structural parts of a level. Like for a house, the outer walls of the house would be struct, and all the walls encasing the bedrooms, kitchen, etc. would all be struct. Detail brushes would be things like a desk, a chair, a computer, a lamp, etc. If you had a bedroom with the walls being structural, and assuming the door had an areaportal, nothing would be rendered outside of the room. However if everything was detailed, the whole house would be drawn at once.
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Bassoon, n. A brazen instrument into which a fool blows out his brains.
Bassoon, n. A brazen instrument into which a fool blows out his brains.