I can't figure out what Jonathan is talking about in regard to walls_invisble. I've tried turning visibility on/off for walls, walls_invisible, and windows to see if this clarifies anything to me. What's the point of walls_invisible?
Jonathan says that walls_invisible "is not going to show up in the render. So if you go over to the render view, you are going to see that these walls are not showing up". It seems to me that they aren't showing up in solid view either. If I hide the walls and windows object in solid view, walls_invisible is well ... invisible. Jonathan goes on to say that these walls "still cast shadows ... so you can use environment light". How's that happen? Obviously I'm missing something. Any other videos at CGCookie that could fill in the gaps for me?
It all has to do with the parametric render style, where you see the room missing some of the walls. It's just a cool thing to do. Because if you think about it, if we try to fit the camera inside the room is going to be difficult, it wont fit and things will be left out of the frame or you'd need a lens that will distort the imagine too much. So what people do to show the entire room is place the camera outside and make some walls invisible or transparent, the ones that would block the view of the room to the inside. But still you need those walls to act as if they are there, because otherwise light would flood the room if those walls were really missing.
So Jonathan has those walls in the scene, they are invisible, so we can look inside the room, but they act as if they were there to prevent the light from entering the room and still cast shadows. They don't show up at render time, because if they would then the view would be blocked. So It's a way for the walls to act as if they were physically there while not seeing them so we can look inside, which is the important part; to be able to look inside the room without walls blocking the view.
