|This article is about an older version of DF.|
 Fortress defense
 3D map format
It's important to remember that 1 z-level up or down is the same distance for dwarf to walk as 1 tile in any horizontal direction. So, rather than moving from a workshop a couple tiles to the door, and then a few tiles down a short hall, and then a couple or more into the side entrance of a "nearby" storeroom (total of maybe 7+), it's closer to put a stair or ramp in that workshop, and for that same dwarf to move over 1, down or up 1, and directly into the what could be the middle of a storeroom on the next level. While this is example uses tiny distances, the idea is the same for larger ones - 15 tiles on one level is the same "distance" as 14 z-levels up or down. And when that distance is repeated hundreds (or thousands?) of times over the life of a fortress, for workshops, for bedrooms, for dining and drinking and breaks, it adds up fast. Optimally, a fortress should be more like a cube, rather than a pancake.
It is also worth noting that when deciding where to go to get something (say, a stone for crafting), when traveling up or down, the locations of stairs/ramps are ignored. This means a dwarf will ignore a stone stockpile three squares from the workstation and travel the long way around to two z-levels down to grab a stone directly underneath them.
For more information on how to dig passages and structures in a 3D map, see digging.
 Interior design
It may seem obvious to experienced players but it should be stated explicitly: for maximal efficiency your dwarves should spend the least amount of time moving about and the most time doing productive things. Fortress interior design is critical to productivity.
One means of fort design is the no-nonsense modern design. Modern style architecture revolves around a no-nonsense approach to space usage, usually with long straight corridors and multi function rooms that contain multiple workshops or other points of interest. A typical modern, 2-tile-wide hallway may appear as below:
║..║ ══┼═══╬┼┼╬═══┼══ ......┼..┼...... ......┼..┼...... ══┼═══╬┼┼╬═══┼══ ║..║
The doors in the hallway lead to large, multifunction rooms. The paired doors at intersections present an excellent method of containment, as a prevention against flooding and also able to be locked against intruders or to contain misbehaving dwarves.
 Diagonal design
In DF, one step orthogonally (East-West or North-South) is the same "distance" as one step diagonally. Diagonal paths thus provide faster access across distances that are not perfectly in line with each other up/down or left/right. Creating a setup with your main high-traffic areas on diagonals, 2 or 3 wide, is less simple to designate, but saves considerable time and effort for your labour force in the long run. Workshops can be grouped so they are staggered, perhaps 4-6 in a cluster, so that the diagonal halls serve them and still no workshop is isolated. Intersections tend to be larger than those of orthogonal passages, but can be designated with stockpiles of booze or other items to make good use of the space. Diagonal passages that are 1-wide act as barriers to both miasma and de-pressurize water (in case of floods), and can be included periodically throughout a design, especially in 3-wide halls where a single, central pillar will not bottleneck traffic significantly. Adding doors at these points is an additional precaution against intruders and accidents.
 Bedroom design
See bedroom design.
 Workshop Logistics
At a certain point, the most important thing for your fortress is not just that you have workshops, but that they are placed efficiently. This can take some forethought and planning to avoid traffic jams and wasted time and effort, but it's usually worth it to have an efficient and smoothly running mature fortress.
See workshop design.
 Miscellaneous strategies
 Use for soil layers
Soil layers (such as clay, loam, etc.) - which may at first seem to be of secondary importance - are very useful for large storage areas, as they do not leave rock behind when dug through and may be excavated much faster by comparison. You can also farm on soil tiles without first making them muddy.
Since soil cannot be smoothed or detailed, it is a less than ideal medium to assign rooms in. Workshops do not have happy thoughts for increased surrounding worth, so if proximity to another area is not an issue, soil is a great place to put them.
Since soil is primarily located near the surface, where a trade depot is often built, it is very useful to dig out large spaces for furniture and finished goods in soil for several reasons. First, it produces no stone, and is thus very fast to dig out. Secondly, having finished goods as close to the trade depot as possible is necessary for efficient trading.
 Curtain Walls, Orchards and Farmland
Just because your fortress is underground doesn't mean it has to start there! If you have the labour and the means, a wall outside of your fortress gate, enclosing an area, can be a great way to claim a little land for yourself. You don't even necessarily have to use your front gate either, as you can wall in an area completely, with no entrance, and then open a door through the mountain. Though time-consuming, this will allow you to better weather sieges, by a variety of means. The area can be used to plant above-ground crops, or allow trees to grow as an emergency reserve. Natural ponds can be walled into your fortress's overall design, and clever use of underground rivers to feed them can provide fish and turtles even in a siege. Dwarves can also safely work here to avoid cave adaptation. Furthermore, with a good supply of stone you can just mine straight down and build a curtain wall around the entrance, so if you're challenging yourself on a map without a mountain, this is a good long-term strategy for defense against siege.
The C-Chute, or Casualty Chute, is a special internal construction for fortresses with large underground areas mostly disconnected with the surfaces, especially if a fortresses defenses are primarily internal. Basically, a deep pit within the fortress walls, down which goes any dead goblins, wildlife, kolbolds and so forth. They are allowed to decay, but the miasma is too far from the areas dwarfs use to affect your fortress. Once they have rotted away completely, you can enter the chute to retrieve their bones, without ever having to go outside! Also useful for fortresses often under siege, where moving bodies outside is not always possible. This is better than using a room to dispose of the bodies, as the dwarfs dumping the bodies will not have to deal with miasma from other corpses in the dump zone.
 Grave Importance
Dwarves have a long tradition of honoring their dead and while some forts may be too bitter to spare resources on proper burial, others can honor and pay respect to their dead. In this design method, hallways do not always intersect, sometimes leading to dead ends where coffins can be placed as well as statues made in the likeness of the former living. Likewise, workshops can also be placed in the center of a 5x5 grid, with the back and side walls used for statues and coffins. Once the current area is exhausted and the dwarves are satisfied that their work has been completed, the workshop can be disassembled and the dead left to rest in peace.
 Plumbing & Filtering
Consider this; You have a very large fortress with all the amenities, including a well-staffed military, valuable trade goods and engravings and lavish halls. Now imagine that same fort with a well-planned and effective plumbing system, delivering water to various spots throughout the fortress. This could be used for anything from killing enemies, casting obsidian, watering your fields, filling your moats and helping your Dwarves. How do you create such a system, you ask?
First, you're going to need a source of water to draw from. Preferably a river of some sort, because lakes tend to dry up. Design a large cistern/reservoir inside your fortress, this is where you're going to be storing your water supplies. If you're drawing from a source of salt water, make sure the entire reservoir is built out of constructions, or this won't work. You're going to need a few grates and a lot of floodgates for this. Once you have your cistern dug out/constructed, dig a channel from the top level to your water source. Make sure you install a floodgate and a grate in that channel; The grate is there to filter out unwanted pests like Carp and prevent them from getting into your water supply. Make sure to link the floodgate to a lever so you can control the flow of water; While you're at it, you might want to design a separate 'plumbing control room' where all the relevant levers for this will be installed. Make sure that before you fill this cistern up, that you install several seperate exits from the cistern that lead into channels which will funnel water to your other systems.
When you're happy with it, you can go ahead and fill your cistern up. Remember to make sure that all your floodgates are linked to levers; You might want to tack notes onto each one so you don't forget which does which. Now you have an easily controllable water source that you can use for all kinds of purposes, including fishing holes and irrigation systems, not to mention powering water wheels. Incidentally, the abovementioned Grate will not prevent small fish like Salmon from entering your water system. They won't cause any problems and you can fish them out at your leisure.
Linking Screw-pumps to a windmill or your power-supply will change the water pressure so wells will not flood. Using this method a player can have open water-sources at any level of his/her fortress.
This system can take a lot of time, effort and resources to pull off, but if it's done right, you'll have a very well designed, fluid (pardon the pun) system for delivering water to all corners of your fortress. Be creative!
NOTE: I said before that it won't work if your cistern isn't made entirely out of constructions if you are using salt water because of one reason. Apparently, water that is pumped through a Screw Pump will be 'desalinated' and thus turned into fresh, potable water. But if that fresh water touches ANY wall or floor that is not made out of constructions, the ENTIRE BODY of water becomes 'resalinated', and reverts to salt water.