First, I am not a Pro E user, my engineer is, and he is on vacation, so I'm having to deal with this. I have latest version of Adobe Acrobat Pro Extended 3D Viewer. When I open an .asm model, some items are missing. They are on the Root Tree, but do not appear. Any changes to color, wireframe, etc do not help. I noticed that all parts that do appear have a sub-directory in the Root tree. The items that don't appear have no sub-directory. Any ideas? I'm desperate and need to work with this project.