SOLVED
After some more fiddling I finally got custom door sets to work
updating Hobbes instructions.
To add/remove/edit entries on the MCD files you need
--volutar's MCDEdit (
https://www.ufopaedia.org/index.php/MCDEdit). It also comes included with a PCK editing tool,
PCKView can only be used to add/remove/edit the images on .PCK files,
To change the attributes of how the images are used you'll need to edit the MCD files.
Since MCD Edit controls the behavior of doors, it is useful to study another file such as XBASE1 for sliding doors and BARN for traditional doors.
Sliding doors
=UFO door:30 1 (original 0)
Traditional door
=Door:35 1 (original 0)
Alt_MCD:46 Set this to swap the door graphics (IMPORTANT)
I.E. set up the door graphics in Edit PCKs and in their MCD animation.
Follow an example MCD to set it up(you can copy and past from another MCD to get the LOFTs and other settings.
When done in MCD there should be TWO MCD frames for the door.
(not to be confused with the large frame below which PCKs are assigned to create the
MCD frame)
Once the MCD frames are created; say 39 and 40,
for MCD 39 the Alt_MCD:46 is 40.
For MCD 40 the Alt_MCD:46 is 39.
For a sliding door typically MCD 39 would consist of 4 to 8 PCK frames
In 4 frames such as the LIGHTNIN door the last 4 pck frames repeat.
For MCD 40 one of the above PCK frames is used (probably the last opened door frame)
Tile_type:53 should be set to either west wall 1 or north wall 2 depending upon orientation.
If doors fail to open, in my instance, I did not quite understand how Alt_MCD:46 worked.
Once that was learned, then the doors opened.
FYI check Die_MCD:44
If 0 the standard game graphic will be used, if your door is destroyed, if some other number corresponding to an MCD then that tile will appear. If your attributes were copied from another MCD, this may display an entirely unsuitable tile if your door is destroyed.
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edit
Hi Steam,
Thanks for documenting your progress Getting into map editing does seem more daunting than sprite editing!
Have you installed the universal patch and looked at the map bits that fix certain components of the ufo map tiles?
http://www.openxcom.com/mod/darkened-ufo-vanilla-variants
https://openxcom.org/download/extras/universal-patch.zip
May be of use
BTW thanks for these, yes the patch actually downloads on the nightlies, the LIGHNIN was of particular interest since they updated a few things to cover the holes in it from its first release in the 90's.