could it be that like me you are using the advanced rendering plugin rather than the standard photo renderer of version 3?
This issue puzzled me all last week :) but it turns out that in version 3.0 the advanced rendering plugin 1.6 does not compute the floor of the rooms (except for 1 room) and ...

Yes I agree with you wrosun, I have been playing with it most afternoon, and the new version of the renderer is really good.

Thanks for this post wrosun, since last week I was trying to solve this. This morning I finally figured out by chance that I should not use the advanced rendering plug in anymore. And this thread just confirm it. So it is useful to post that kind of issue and its solution.
Note: the reason I kept ...