I have done some simple rendering with Archicad for some time now. I have never bothered with the backgound image not lining up with the model. Does anyone have any idea how to make the model line up with the bottom of a background, so that the clouds, trees, or whatever actually appear above the model not level with it? My current project is in Archicad 8.1, but I assume Archicad 9.0 would respond the same. Thanks.
You'll need to fake up a horizon line in Photoshop by adding it to the image or use the LightWorks Background feature "Match View" to relocate the background image as indicated on page 26 of my essential and great value book "LightWorks in ArchiCAD," now including special ArchiCAD 10 supplement (Registered book owners will receive notice of the location to download their update during May, after I actually write the supplement, once I'm absolutely certain of the changes implemented).
"Match View" enables the shifting of an image using dimensional displacement. There's no preview, so you need to do some trial and error.
In view of the fact that ArchiCAD 8.1, an ancient form of ArchiCAD known only to the Neanderthals and incapable of anything beyond mud huts, doesn't have the LightWorks rendering engine (introduced in ArchiCAD 9 and carried through with much disappointment almost as is for ArchiCAD 10) the answer is "no."
You must make it up in Photoshop.
BTW: this is the better practice in any event since the LightWorks method doesn't provide a preview and can consequently be cumbersome to employ.