Seems like a very difficult, if not impossible, way to manage a model tree or hierarchy. For example if I have a machine with hundreds of part and assys and I need the covers to be at or near the top of the tree. When the user opens the PDF the covers should be at the top level of a model tree.
The model tree import relates to the hierarchy of the CAD Assembly model when the direct translators are used. Can you expand on what CAD system you are using. I will use for an example Solidworks. If I import an assembly from solidworks by drag and dropping the assembly into A3D, then make sure to select U3D (you can not edit a PRC file in 3DTK) the Tree will be exactly the same as it was in Solidworks, If you want to change it, activate the model in A3D, Right Mouse Click and select "Edit in 3D Tool Kit" Once in 3DTK Hit "F3" or go to the Edit menu and pick "Select Objects" in your case you can search for "Covers" it will find all covers, once found, close the dialoge, then Right mouse click on one of the selected covers and select "Create Group" at the bottom of the Tree, you will see "Group" double click it and rename it. That should take some pain from you.
Tim Huff
North American TAM Manager
[link=http://acrobat.timhuff.net/] My Blog - I didn't know Acrobat could do that! [/link]
Jim Merry, VP 3D PDF, Tetra 4D, jim [dot] merry [at] tetra4d [dot] com