open porch issues in General Q & A Posted Friday at 04:14 AM 2 hours ago, GeneDavis said: Nice presentation and discussion, Eric. I think the OP has a situation where the new structure is going to be built atop the asbuilt slab, and its wall lines will be inside those slab edges. Like maybe a foot. So he may just want to make his slab, the one Chief builds for him under his porch, invisible material, and let the asbuilt slab show. Or put it on its own layer, and turn off the layer display. Or open below, or remove the floor in this room option.