Vanishing Point function isn't strictly 3D, but a separate filter that offers things like the ability to clone stuff and have it be the right shape and size in the place it is cloned to. For example, in the above image, the painting could be moved to the left or right and take on the shape/size so that it would look like it was physically moved.
Out of curiosity, Andy, is your intent to be able to move things around? Or have you found a more sophisticated way to use it?
I have only used the Vanishing Point filter a few times, and I only ever saw the need to define the plane for the specific things I was (Clone) Stamping - not model the entire reality of the photo.
In CS6 Extended, at least, the Vanishing Point filter can create a 3D Layer containing the defined planes as "postcards" and a camera set up to match the perspective defined by the floor plane (which has to be the first one drawn, I believe). I'm not saying that it works reliably, though.
Then you would merge a 3D Layer containing your object to be rendered with that layer containing the temporary "postcards" and camera.
That's why I suggested using the orthographic views and these planes to position the painting on the wall plane. It will need a little sliding on the wall plane to get it into the required position. Then hide the "postcards", render the object and composite with the original image.
I don't know if CS5 Extended can do all that, though.
You can rotate the camera to see top down, this will allow you a better view to align objects depth wise. there are also preset for viewing top, bottom, left, right, front or back and finally default perspective. If I recall it has a few preset for other perspective views, but that is moot for this thread.
Since the vanishing point filter produces a 2d mesh, from the top, it would look like a single line since it does not have any depth.
Thanks everyone for the replies!
First let me try to briefly explain my current workflow when constructing these room settings. I'm certainly not saying this is the best/most efficient way to build them, but it works for me. The main advantage for this method is that it seems to keep everything in the room in proper perspective.
1. The first step is to obviously clip the raw camera shots from the photographer and place into PS. However, I first choose what is to be the focal piece of the room, whether it be the bed in a bedroom, or in this case, a corner desk in an office.
2. I use the focal piece's perspective to construct all walls of the room using Vanishing Point. I start by building a plane from a rectangular area of the focal piece, then keeping that perspective intact, build all remaining walls, floor and celing from it (note: shots below are from a
room still in progress).
3. Of course the next step (and the most painful, haha) would be to match up all remaining pieces to the perspective just established. This often requires chopping things up and reassembling. In addition, if you can tell, I've set my planes in dimensions of feet, hence the 8 foot ceilings in the above room. I believe the corner desk shown is about 61".
Here is a much more finished bedroom assembled using the same method:
I have foud that Vanishing Point can give me quite funky perspective planes at times when I base it off of certain pieces. Not sure if any of you have experimented in this way or not, but using Ctrl or Cmd drag on the edge of planes (which is supposed to tear of a new plane at 90 degrees) sometimes gives unexpected results. However, I've found if I slightly lessen the severity of the "focal piece"'s angles, it helps.
I know this is quite the long post, and I apologize, but conroy, I don't believe CS5 has the capabilities in VP that you're speaking of. However, it sounds very intriguing and if/when I get CS6 I'll certainly give that method a whirl.
Thanks again for everyone's feedback, maybe I've sparked some interest as well in the area of digital room settings. If any of you have suggestions, tips or better ways of creating these I would welcome any and all help. I'm a freelancer and these take up a good bit of my work.