Okay, TBS newbie here (haven’t installed it yet)… But, while waiting for everything to come together so that I can install it, I have watched some online demos and looked at some of the free tutorials as well as a couple Work Out series that I purchased.
This is probably a really stupid question, but it’s something that I’ve been trying to wrap my brain around. My question is concerning the camera (which moves in 3D) and the 2D world. Say you have a house. You have the drawing of the front of the house. You follow the character through the door. You see a couch, a TV, a lamp, and a table. And then you can see out the window on the back wall. You can move in closer to the back wall, to see what the character is watching out the window. All these are 2D objects in 3D space, basically, right? As though you layered them, one on top of the other, on paper, but in 3D space to provide perspective in moving forward and back? Like you’re holding the drawing of the front of the house a few inches in front of the drawing of the back of the house?
The question is, where are the side walls? When the character walks through the front door, how do you not see the trees (or whatever) outside the house where the side walls should be?
hi and welcome 
to your question: the 2d objects are simple planes in the 3d space, as soon as you pass by a plane with drawn elements, then there is nothing more from the previous sight. and the camera can only look forward. so for back walls you’d have to create a new plane with walls, further in the 3d space from the camera.
the side walls are not necessary, because the camera can’t look to the side.
so this is like a ‘fake’ 3d, not the one from 3d environments.
hope it helps.
cheers,
rob