I vaguely recall eventually figuring these out in NWN1, but I´m having a headache now trying to emulate that task in new toolset...
So...
It is even easier now to hide the doors etc within walls and make them look like they´re part of it, but it doesn´t help a lot when a cursor tells you it´s "Da Secret Door". Tried to play with triggers named alike, too, but so far I haven´t managed to find anywhere how I could determine things like spot DC etc for said doors and how to actually make them secret.
I´m willing to wear a noob hat and sit in the corner for an indetermined time if someone would just explain to me how this stuff work, preferably in grunts and short sentences as I´m really having a dumb now.
Wynna agonized over this very question for a long time, and came up with some very clever solutions if I recall correctly. Unfortunately, I don't remember what they were offhand. One could write a script to attach to a trigger in the vicinity of the door, which does the hidden search checks, and spawns in a secret door with accompanying message, provided said door was a placeable that looked like a door (not sure if spawning doors works).
It's a challenge even for the script/toolset-adept, so don't feel down for lack of success. Concentrate on the rest of whatever you're working on for now, and we'll try to fill in some helpful pointers as possible for the hard bits.
I had the same problem, too. I think I duplicated the door and moved it forward slightly and made it static. Then when you find your secret door delete the one hiding the real door. Stops NPCS walking through it, too.
I don't use doors at all when I want a secret door. Instead, I use a tile with a doorway, then fill that doorway with an invisible collision box with a unique tag. Then I put a wardrobe or picture or tapestry or curtain or what have you in front of the doorway so that it's completely hidden. If it's a wardrobe, I also use a black tileblock sized to fit INSIDE the wardrobe without protruding through the closed doors so that when they open, there is a black doorway in the back of the wardrobe/wall. If it's a wardrobe, you can script the collision box to destroy onopen of the wardrobe and return onclose. If it's a curtain, I script a search check trigger that makes the curtain usable if the PC passes the search check, then script an onuse for the curtain that makes it "draw aside" (If you're really ambitious, you can script the disappearance of the closed curtain and the appearance of an open curtain) and destroys the collision box.
Point is, use placeables and triggers and placeable scripts, not the useless secret doors. If we had a set of placeable doors, it'd be much simpler. Then you could dispense with the collision box and blackout tilebox behind your obscuring placeable and set the door to unusable until it's discovered.
I have an idea now how to handle this in this particular case. Just gotta get my hands dirty with scripts that have traditionally been a spook for me, but it´s about a time to tackle that thing and I found few nice tutorials to help with that. (In addition of reading that Lilac Soul´s should be fairly compatible still, someone said 95% compatible even... Any experience of if this is true anyone?)
A cheap solution to this problem is to have the name of the placeable secret door read something like "Secret Door ((Spot Check vs. DC 20))" and hope/trust the player decides to respect RP and make an individual Spot roll before reacting to it.
