Hi Alan, I missed your post. Perhaps I do not understand Walter's question, but the following is what I understand. Btw, by back face, do you mean the unseen faces behind the ones you can see in the scene? If so I did the following with some success.
"Select all" in the scene with right to left window, and explode as necessary to eliminate all components and groups.
"Select" in the scene with a left to right window, then "add" to "select"ed, the individual faces at the perimeter of the scene.
Make the combined selection into a component, using default name, but "do not replace selection with component".
Open component menu, select "model" components, select the default name component, then "save as" skp file.
The saved file, includes only the faces that can be seen in the scene. They include however, portions of the visible faces that are behind other visible faces.
Open the "default component name" file, but do not save changes to the original file.
Step 2 only selects the visible faces completely within the select window, and the balance of the faces along the perimeter must be individually selected. You can skip step 1 if you want the components, and groups to be part of the new file. It will however, contain the back faces within each component, and group.
