So you want to create an ortho from cut, not from the above?
In CAD, is your ortho as some kind of a background for drawing?
In this cases it is important to have a correct heights. In RealityCapture it is Z axis. In AutoCAD it will be Y axis, because it is only 2D system.
So, what you need to do is change these values in tfw file (I think last two vales are the coordinates of left upper corner of the ortho). One value is height and the other is for position. The height should be last in this case.
Also, are your models georeferenced?