It is different in Poser 13. Like, the same file rendered in Poser 13 comes out with that beige BG, while it renders with a black BG in Poser 11.

The way I typically do it is to set the ground to visible, but invisible in camera. (I like seeing the grid when I'm setting up a scene.) Then I set it to "render over black" in Render Settings.

This is much more convenient. I want the construct to be visible (just not rendered), and I don't want it black. I find it a lot harder to work with a black background. I want to see the grid lines.