About working doors and windows il TRY to explain it in brief test
For the doors, after materializing etc, in polymode, detach both the left and right
Then name them DOOR_LEFT and DOOR_RIGHT
Then, polymode, select each door you detached, and make sure you do Selected none, on both of them
Then polymode on TDU's DOOR_L and DOOR_R and Select All on both of them
Back to normal mode,
Make sure Diffuse color is off on DOOR_L and DOOR_R of tdu, by right clicking, properties, dont remember by heart, something in vertex.
And then attach DOOR_LEFT do DOOR_L, same for DOOR_RIGHT to DOOR_R, poly mode on each, selected mode, Deleted, selected mode off.
Now go to
Modify->Move->White square next to it, and Move pivot only or something like that
Then show only DOOR_R, and on Left View use the Move to move the pivot to its extreme left middle position, and on top view put it on more or less the same place you put it on left view, but it has to be on the door :) then do the same for the other door!
There you should have working doors!
For windows, detach them from the model ur converting
rename WINDOW_LEFT and WINDOW_RIGHT
polymode on each of them, select none, normal mode
Poly mode on tdu's window's, select all on each.
Dont forget diffuse colors off, on the window
I think window model is WND_R1 and WND_L1
attach window left to tdu's window left and do same for other window, polymode selected mode, delete.
And then, on the move, make pivot only, and move each window pivot to its middle bottom on the left view, and top view make it on the middle, but in the window, do on both windows.
Then WND_R2 and WND_L2 should be dummy's, just move them to where the window will be when its open ;)
Thats it
Mirrors are just TOO Long to write here!
Good luck ;)