Hi All The ceiling plan which I am working on is a blown-off. First, its XY plan is very complicated, it consists of many shapes but, what is more difficult is that its Z elevation is changing as well (as the sea surface). So my problem is how to change the Z-coordinates of my XY ceiling plan to reflect its variation in Z-axis. I can not find anything straight forward in the text books I have so I ask you for help. I had an idea to use either VBA or AutoLisp, but I was hoping that those scripts already exist and somebody would be so king to give me such a script. The script should take two objects, one is the planar XY plan of my ceiling and the other is the XYZ mesh or edge surface and use it to update the Z coordinates of the ceiling plan. The output should be the new XYZ edge surface with updated XYZ points from ceiling plan. If somebody can help me with this it would be great. thanks in advance ewa