If I were going to do something like this I would create a smooth seamless background something like in the image below. You need the floor and walls to help keep the light in. But I would make the surface an illuminator (wrong term for V-ray I’m sure) so it’s entirely white with no shadows. Then in an image editor I would set the rendered image’s layer to Multiply so the white background appears as transparent. You could, of course, make the background pixels transparent, too.
It’ll be interesting to see what Eric comes back with.
Trying to remember how you do this away from my computer (at 3D basecamp also) , but there are a couple of ways I think you could do this.
If you are saving as PNG file the background should be transparent automatically - however if you’ve used a backdrop of a lighting studio or floor plane , then that is a physical thing. That will show.
If you find the material that you’ve used in the backdrop “fabric” there is somewhere where you can make that material invisible to the camera , but not to the lighting calculations.
Then when you export it as PNG , it should not be there
Most rendering programs have the ability to render with an “alpha channel”. This is what you are looking for. Unfortunately, I don’t know Vray. From what I remember, in the Frame buffer window you have the option to select the alpha channel and save it.
This additional geometry is not necessary. It was a must for traditional photography. Here it is enough to have a fairly large area of white floor and use the white color of the sky in the environment settings. It’s everything. Adding an illumination to the floor material does not make sense - the material will illuminate the model and distort the shadows. And the arrangement of the armchairs in your example also makes no sense. Always position models as far away from walls as possible to avoid unwanted shadows