Hello, I've tried following these steps several times, I keep getting stuck once I change the room type into open below.... it pretty much does exactly that - opens the ground below and shows the backdrop in 3d view. I've tried placing a slab, however, this is what I get (snapshot attached). And oh, I used the gingham pool texture on the slab.
What am I missing? I've tried Renerabbit's video method, but it didn't work very well either, I dont' think his method was created for an indoor pool, as the room walls keep attaching itself to the existing ceiling no matter how much I try to edit the specs.
