Dimensional Dungeons

Dimensional Dungeons are dangerous pocket dimensions that mainly consist of Fabric of Reality and Stone Bricks. There are wooden dimensional doors that link to the Overworld, and iron dimensional doors, sometimes many, that take you to new rooms of the dungeon. Dimensional Dungeons are rich with opportunities for exploration and loot. The different maze-like rooms can house chests, Redstone traps, hidden areas, a hidden Block of Diamond, and so forth. The chests usually contain objects that are valuable, rare, or unable to be crafted, such as Music Disks, Fabric of Reality, Saddles, and more.

Finding Dimensional Dungeons
To enter a Dimensional Dungeon, you must locate a Rift Gateway. These are structures made of stone bricks, cracked stone bricks and chiseled stone bricks that spawn in the Overworld and Mystcraft Ages. They consist of two three-block-high pillars with a Rift between them. By walking into the Rift, you teleport into a Dimensional Dungeon. Rifts that do not have doors placed on them can become unstable and no longer teleport players.

Advice for Traversing Dimensional Dungeons
Dimensional Dungeons consist largely of Fabric of Reality. The block is solid black, so it is hard to differentiate it from air.

If you die in a Dimensional Dungeon, be it from TNT, falling into the void, or any other way, you are sent to Limbo. Limbo is a dark place made of only Unraveled Fabric.

Always be on the lookout for pressure plates and tripwires! If you stumble upon a piston trap, you can break through the wall and modify the Redstone contraption to your liking.

If you hear TNT lighting, think before running on instinct. More likely than not, you will have activated a second trap. One example is a TNT trap that also opens a hole in the floor behind you.

If the floor of a room is made of Fabric of Reality, it can be difficult to differentiate between solid ground and a hole that sends you falling into the void. One way to find out if there really is ground under you without risking jumping and possibly dying is to hold the shift key while walking; this way you will never walk off the edge. There are also rooms that look like holes, but have treasure chests hidden under them, disguised with Fabric of Reality to try to convince you that it is a dead end.

A bucket of water is a handy tool to bring with you. It can be used to test for solid floors, set off tripwires from a safe(er) distance, and wet TNT blocks to cancel their damage to chests and blocks. Always be ready to drop a bucket of water on the floor when going deeper into the dungeon, as many traps involve the player spawning directly on top of a pressure plate when entering a room.

The use of an Ender Chest provides a convenient way to get collected loot out of a pocket dimension. A single chest can be used to store items so they will not be lost if you are killed, or a pair of chests can be used to safely teleport items to another location where they can then be removed automatically or by a co-operating player. Bring a pickaxe to pick up the chest and take it with you before moving on.

If you find yourself getting lost, you can use blocks to brick up doors you have already traveled through or that you know are dangerous to use. Alternatively, you can keep yourself oriented by placing signs as you go.

Carry a few spare Warp Doors (or the materials to craft them) as an emergency escape measure, or to replace a warp door that has been destroyed by a TNT trap. Note that Transdimensional Trapdoors will deposit the player into the Void (and death) if they are too deep into the pocket dimensions, and are therefore unreliable.

It can be helpful insurance to carry flint-and-steel in case you find yourself trapped in a Dimensional Dungeon unable to return to the Overworld. There is a type of room in the dungeons that contains netherrack and always has an obsidian frame. With a flint-and-steel, the obsidian frame can be activated to create a Nether Portal. From the Nether, you can then travel to the Overworld.

One way to "cheat" through dungeons much more easily is to use a texture pack that makes Fabric of Reality visible.