The Quad-Sectioned Military Door - a component inspired by id Software level
                                   E2M1 and originated from The Quakelab.
                                   Re-textured and adapted for qED by
                                   JF Groleau.

The QuakeLab - http://www.planetquake.com/QuakeLab
The qED Toolshed - http://www.cam.org/~jfgrol/
3D-Matrix University - http://www.3dmatrix.com/serv03.htm

TEXTURES USED:

        tech13_2 for door panels
        tech11_2 and tech09_3 for door frame except side faces
        tech06_2 for door frame side faces
        tech02_6 for inner frame plugs and mini-slab brushes

ENTITIES:

        func_door

WHAT TO DO:

        Extract the .qgp file from the archive and place it in the
        c:\Program Files\qED\Group folder. Once in qED, insert this prefab
        using the menu item "Group" + "load from library". The origin of this
        prefab is at the center of the door assembly and flush with floor
        level. The position or offset of the inserted group will be in
        reference to the offset of the currently selected item in the level
        outline window. The group can then be moved and rotated to suit the
        map design. Some texture alignment might be required after these
        operations. The 3D-Matrix university provide exhaustive tutorials on
        this topic. Also, inside the main group is a subgroup called "wall
        cutting". This subgroup contains a negative brush which has the same
        overall side dimensions as the door assembly: use this to cut an
        opening in the wall in which the door will be placed. First, using
        the level outline view, move the wall into the cutting subgroup and
        reposition it in the 2D-views if necessary. Then do a "subtract
        brushes" on the cutting group and move the resulting brushes to
        their original group. Rename the brushes appropriately if needed
        and reposition them if necessary. 


Note: Just make sure that the wall in which the door panels will slide into 
      is thicker than the door itself which is 16 units thick.
      Also make sure that the negative brush used to cut the wall opening is
      thicker than the wall itself. Adjust negative brush size accordingly.
      Lastly, using the cutting group to create an opening in the wall is
      very important. This way, you absolutely sure that the only brushes
      that will be cut are the ones you really want to. Protect your work.

FUNCTIONALITY:

      4 func_door entities and their child brushes, one for each door panel, 
      The base door sound attribute (2) is assigned to only 2 door entities:
      one for each pair of doors to avoid out-of-sync sounds. The speed value
      of the top and bottom doors is set to a higher value than the left and
      right doors to provide a nicer effect and also avoid out-of sync sounds.
      The door frame is 256w x 192h x 48d units and needs to be sunk into the
      the floor by 48 units. This is why the origin of the group is 48 units
      above the bottom of the door frame and thus flush with the floor. Total
      door surface is 128h x 96h x 16d units. I completely re-textured this
      prefab from the original Quakelab version which was more similar to the
      one found in Quake level E2M1. The reason for this is that I found that
      the original door texture made little sense with respect to the shape
      of the individual panels. The other textures were changed to make the
      whole blend together accordingly. A group of "mini-slab" brushes were
      added to provide a guide for the ceiling and floor height as well as
      their respective thicknesses in case the door is placed in a room with
      other rooms above or below it. This group can be deleted once everything
      is in place. Also, inside the frame, is a group of "frame plug" brushes.
      These 4 brushes are included in case the door is used in a short narrow
      corridor the same size as the frame to avoid leaks. Depending on the
      particular location of the door in the map, one or several of these
      brushes could be deleted (more often the side ones) to reduce brush
      count, just be careful not to create any leaks.

OPTIONS:

      Speed of top and bottom doors is set to 50, left and right doors to 40.
      This can be changed to according to your taste but I find that the effect
      looks nicer when the top & bottom move faster than the left & right.

CREDITS:

      Id Software (http://www.idsoftware.com/):

         For Quake, the best first-person game of the known universe.  The
         military quad-sectionned door is an Id original from level E2M1.

      Steve Fukuda (stevefu@unixg.ubc.ca): 

         The original builder of this cool prefab. Thanks for sparing me the
         nightmare often involved in brush subtraction of odd shapes. In this
         case, the door panels.