The hidden doors mod adds in the ability to create doors, which take on the texture of whatever they are placed on. This allows you to create a hidden passage into any anything you create. What Does This Mod Add To Minecraft? This is a relatively simple mod, but it is interesting none the less because of its usage.
To create a hidden door, you just need 6 bookcases. After you have them, put them in a crafting box in the regular shape of a door. You then place the door onto whatever block you what the texture of the door to be. For example, if you place this door on a wooden plank block, the door will appear as two vertical wooden planks, but it will still function as a door. This works for all textures in the game. If you place the door on cobblestone, it will look like cobblestone etc.
While this mod has some applications in single player, it really shines on multiplayer servers. This is because you are much more able to camouflage your base’s entrance. That is assuming that you build into a mountain or something that looks like it belongs in the environment. It wouldn’t be effective at all if you were to build a shelter out of wood planks and then use the hidden door. This is because they would still be able to get into your home by destroying the walls. The only problem with this method would be acquiring the 6 book cases since they can be quite expensive early in the game.