EXTF                                                                Menu: UTIL
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Extracts part of the model to an external file.

        1. (CHAR) name of extract file (1-7 char.)
     if file name exists:
        2. (Y/N) file (name) already exists, wish to overwrite?
     if file name does not exist or reply is `y':
        3. (Y/N) wish to delete the extracted entities from source file?
        4. (Y/N) wish to open the extracted file?

Description:
This command transfers all the entities and instances (placed objects)
included in the selection group to a separate file.
You are asked to specify the extract file name (up to seven characters). If
a file of that name already exists, you will be informed and asked if you wish
to overwrite it. You are asked whether you wish to open the extract file or to
stay in the current file (the default). You are then asked whether the
extracted entities are to be deleted from the current (source) file or not
(the default). If you choose to open the extract file all the selected
entities are transferred to the new file. The current file is then closed and
the new file is opened by the system.
The new file contains only those selected parts of the original file that were
extracted. When dealing with a large model you may extract a part to be worked
on, avoiding irrelevant data that may slow system response time. After
elaborating this part of the model (adding and/or modifying) you may return it
to the original source file by using the \retf command.
Note that if you add or update walls in the extracted model, then when you
return to the source file you may have to fix their intersections with those
walls that were not transferred.

        Example: \extf inter1 y y

Result: The entities and objects included in the selection group are
transferred to the file named inter1. The file is opened by the system for
work. Your current file is closed and saved.
