Ok I am making a HUGE assumption here...in the photo I have picked..to get the ground plane ROUGHLY orientated...I have assumed the following dimensions on the photo itself. Now taking those I create a right angle triangle under the plane then place that plane on the hypotenuse and place the FRONT of the ground plane at the start/bottom of the image. My plane will be behind the image so to speak..then place the objects on the newly created ground plane??

cheers bullet