OPLAC                                                              Menu: WALLS
==============================================================================
Inserts an opening into a wall.

        1.   (CHAR) name of opening (1-8 char.)
        2.   (NUM) dimensions of opening (sx,sz)
        3.   (NUM) height above axis
        4.   (IND) axis of opening
        5.   (Y/N) confirm choice
        6. * (POINT) place of opening (on axis)
             (press <ENTER> for another axis)
     if file name does not exist:
        7.   (CHAR) file (name) does not exist, enter another name
     if file is empty:
        7.   (CHAR) opening file (name) is empty, enter another name
Description:
This command inserts into a wall an opening (an object that is an external
file). Enter the file name of the opening you want to insert. Specify the
width and height of the opening, and the relative height of the opening above
the wall axis. The default value of the relative height is 0. Indicate the
wall axis on which you wish to place your opening. Confirm your choice of axis
and pick the exact location for the opening. The opening will then assume the
same width and direction as the wall on which it is placed.
The standard opening is best created as a 1 by 1 by 1 negative solid with
0 0 0 at its lower-left corner. The width and the height may be then given as
simple expressions in the current units. The remaining dimension is always the
width of the wall in which the opening is placed, and it is calculated
automatically.
If the file name specified after the first prompt does not exist or is empty,
you will be notified. You may specify another name, and all other parameters
remain unchanged.
You may place openings of the same wall before entering another command. If
you wish to place the opening in another wall press <ENTER> and you will be
prompted to specify another axis. Only pre-designed objects may be placed
using this command.
