See hborre's answer above. If you want something to scale, use a background image on a plane and one of the other images on a light instead of the sphere....you won't get accurate scale with the envirosphere. The sphere is used mostly for sky images. I use Alex's apartment all the time, but I only use it for reflections and light, so I make the sphere invisible to the camera. The light still shines and surfaces still reflect the light from it, but you don't see the image from it. I then build a scene around it if that's what I'm after. Normally, I don't build a 360 degree scene, which is why I use the sphere to begin with. I make a lot of metal shaders and they need something to reflect (as does skin, btw). I only set the sphere to visible if I have a sky image on it and my scene requires that the sky be seen.

Laurie