The Bruce Iris hatch - a component designed by Iain Bruce
                       and originated from The Quakelab.
                       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:

        tech08_2 for the hatch doors
        door02_7 for the hatch frame

ENTITIES:

        func_door, trigger_multiple

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 middle center of the hatch assembly.
        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* 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 "floor cutting".
        This subgroup contains a negative brush which has the same
        overall side dimensions as the hatch assembly: use this to cut an
        opening in the floor in which the hatch will be placed. First, using
        the level outline view, move the floor 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 floor in which the hatch panels will slide into 
      extends above and below the top and bottom of the frame slot. Otherwise,
      the hatch panels might show through the ceiling of the room below the hatch
      or through the floor of the room above the hatch.

      Also make sure that the negative brush used to cut the floor opening is
      thicker than the floor 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.

*IMPORTANT: This qED group was made by converting an existing map file.
            Because of the difference between the way the map format and the
            qED file format define brushes, 2 custom (.qbt files) brushes had
            to be made in order for the doors to line up properly. It is *not*
            recommended that the prefab be rotated once inserted in the map
            and I do urge you to resist the urge to "normalize" the door brushes
            because this will screw them up badly. However, if you do decide to
            experiment with angles and inadvertently ruin your door brushes, you
            can always replace them with fresh ones since I have included the 2
            .qbt files with this archive. Just copy those to the brush sub-folder
            under Program files\qED and restart qED. They show up in the "custom"
            category as Wedge 1 and Wedge 2. Wedge 1 is used for the 0, 90, 180,
            and 270 degree angle brushes while Wedge 2 is for the 45, 135, 225
            and 315 degree angle brushes. Remember, the brush vertices in the
            resulting map file must all line up on a 2 unit grid minimum so
            watch out for those odd numbers.


FUNCTIONALITY:

      8 func_door entities and their child brushes, one for each door panel, 
      The stone door sound attribute (2) is assigned to standard base.
      The speed value for all the hatch doors is set to 10. This makes it open
      nice and slow. If you change the speed, you have to change all the door
      entities, otherwise the hatch will not work properly. Also, you will notice
      that the doors actually move in a direction opposite to their angle
      attribute. This is due to the lip attribute being much higher that the width
      of the doors themselves. This particularity is what makes the hatch work
      properly and in perfect sync since the lip and speed attributes interact in
      some way. The hatch displays small gaps when opening and 4 of these remain
      once it is open. Attempting to to tweak these values to eliminate the gaps
      is futile since they represent the best compromise already. With the proper
      lighting, these gaps are virtually unnoticeable anyway.

      The hatch frame is 256w x 256d x 48h units and overall hatch size is about
      160w x 160d x 16d units.
      

OPTIONS:

      Not too many except for textures. Experiment at your own risk.

CREDITS:

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

         For Quake, the best first-person game of the known universe.

      Iain Bruce (pibruce@island.net is the last known address though
                  invalid now, e-mail me if you know):

         The designer of this work of pure genius. Very cool!