I looked at all the currently supported culling methods, and none of them is a culling method that can handle large indoor-outdoor mixes very well. In particular, these rooms have a large number of channels, when the door of the room is not always closed. Then, even when I facing a wall with only a few triangles, the number of DRAWS can exceed 2000, it’s sad to just look at this number …
Maybe you would say, why not culling distance? Maybe, but I don’t think this is a good solution, because it allows users to see all objects jumping up and down, and it is difficult to adjust this distance to a suitable value.
The occlusion query? It still needs a lot of rendering resources, because as long as you don’t draw, you don’t know whether to draw or not. But portals+rooms rendering can easily identify rooms that users cannot see.