Composite furniture into interior help

[dlparisi]

Hi everyone,

I've got a job where they are asking to render out entourage into an existing office interior (see below). Getting the furniture in place and camera matched is not a problem but compositing it with shadows and reflections is looking to be a problem for me. I've got a quick simple version of the existing interior modeled and roughly aligned with the photo for testing but I just can't seem to work out how to get the shadows and reflections of just the furniture and not anything else. Setting the rough model to a shadow catcher (or many other combinations) isn't getting me what I need. Unlike most examples I've seen (and done myself) I don't just have a ground plane that needs shadows on it. I have sunlight coming in through the windows and skylights illuminating the new furniture. If I set the existing model to a Shadow catcher, the alpha is useless because it's essentially getting a giant shadow on it from the ceiling above (with holes for the skylight) so it's mostly pure white except where the skylights light the sun through. Is there any way to exclude the ceiling shadows from showing up on the floor alpha but still get shadows from the furniture (mostly indirect contact shadows)? Any ideas on how to go about this efficiently?

Photo:


Alpha with walls, floor and ceiling set as shadows catcher. Obviously there's also a teapot in the center that I'm trying to get shadows from too:

[fixeighted]

I'm thinking along the lines of a fairly accurate model that you camera project an adjusted texture onto (getting rid of existing lighting where possible).
That may be less hassle than dealing with mattes and comping various bits etc.
I can't do an example as my pc is screwed for Max at the moment, but I'm sure you get the idea

[fixeighted]

Actually, I got a few minutes of render time before crashing so tested this and it works very well, given the relative simplicity of the geometry in the image, so it might be a good solution for you.

[dlparisi]

Thanks for the response and effort. I think this is how I'm going to go as well but I think I'll limit the rendered portion to just the floor and new furniture (the walls really should stay as is). That way I don't need to worry about compositing the shadows on the floor but I should still be able to mask out different furniture pieces for adjustment in Photoshop. The existing photo has some overly aggressive hdr effect and sharpening on it too which I think I need to try to mimic after the fact in Photoshop as well. Thanks again.