Info: Mobility

## Mobility

How much mobility stuff costs.

Mobility represents the amount of time and energy it takes to do something. In "Real Life" a ground offensive takes hours. In Empire, it takes less than a second. Now the way Empire \*could\* work would be for you to give your troops "orders" and then wait a "realistic" amount of time for them to carry these orders out. But who wants to type "nav 15 yh" and then wait 30 minutes for the ship to get there? Certainly not you! That's why mobility was invented. Every update, all of your units and sectors get more mobility, and that means that enough time has passed for you to be able to do more stuff!

In Empire, four things have mobility: sectors, ships, planes, and land units. You can see how much mobility each of these gets every update in the output of the "version" command:

```
Sectors Ships Planes Units
Maximum mobility 127 127 127 127
Max mob gain per update 60 120 90 90

```

If the mobility cost for something is a fraction, for example 2.4, then there will be a percentage chance that the actual cost is rounded up or down. In our example, there would be a 60% chance that 2.4 is rounded down to 2 and a 40% chance that it is rounded up to 3.

## Land Units

Land units are charged mobility for the following actions:

### Fighting

See Info: Attacking for the mobility cost to attack.

### Fighting rebels

For each 2 points of efficiency a land unit loses fighting rebels at the update, it loses one point of mobility.

### Fortification

Fortifying a land unit ("dig in") costs one point of mobility per point of fortification. An engineer cuts the mobility cost by one third. See Info: fortify.

### Converting civilians

Security units are charged 10 mobility every time civilians are converted in a sector they are in.

### Laying mines

A land unit is charged one point of mobility for every land mine laid.

### Work

The increase in efficiency depends on mobility used. It costs a 100% efficient land unit 6 mobility to raise a sector 1% efficiency. Less efficient land units are charged proportionally higher amounts of mobility. For example, a 50% land unit would be charged 12 mobility to raise the efficiency of a sector by 1%.

### Supply

When supply is drawn from a supply unit, that unit pays the mobility cost to move the goods to the destination sector. That cost is the same as it would cost the sector to move the goods using the "move" command.

### Marching, reacting or retreating

The mobility cost for a land unit to march, react or retreat is:

```
(path cost) * 5 * 480 / (unit speed)

```

where

```
unit speed = speed * (1 + (tech factor))
tech factor = (50 + tech) / (200 + tech)

```

See "Path Cost" below for the path cost formula. Note that reacting land units only pay mobility to move "to" the attacked sector; they return to their start sector for free. Land units on "reserve" mission only pay half the mobility cost to react.

Marching through newly taken sectors (not old-owned, no mobility) costs extra mobility equivalent to a path cost of 0.2.

Note that the efficiency of a land unit does not affect the mobility costs it pays to march, unless the unit is a supply unit. Then the mobility costs are proportional to the efficiency of the unit.

### 9. Shell damage

When a land unit is shelled, its mobility goes down in exactly the same way that its efficiency goes down (see Info: Damage).

## Planes

Plane mobility can never go below -32. Planes are charged mobility for the following:

### Air combat

For every two points of damage the plane takes from air combat, the plane loses one point of mobility.

### Launching satellites

A satellite is charged one point of mobility for each sector it passes over in its launch trajectory.

### Flying

The mobility cost for a plane to fly is:

```
5 + (flight cost) * (distance flown) / (max distance plane can fly)

```

For escorts and interceptors, the flight cost is:

```
10 / (plane efficiency)

```

For all other flights, the flight cost is:

```
20 / (plane efficiency)

```

### Land mine, pin-bombing, and nuclear damage

A land mine, pinpoint bomb or nuclear detonation will damage the mobility of the plane in exactly the same way that the efficiency of the plane is damaged (see Info: Damage).

## Ships

Ships are charged mobility for the following:

### Firing a shell

The mobility cost to fire a shell is 15, unless the NOMOBCOST option is enabled in which case ships are charged nothing.

### Firing a torpedo

The cost for a ship to fire a torpedo is one half of the cost for it to move one sector.

### Boarding a ship from a ship

See Info: Attacking for the mobility cost to board a ship from a ship.

### Navigating and retreating

The mobility cost for a ship to navigate or retreat is:

```
(sectors traveled) * 480 / (ship speed)

```

where

```
ship speed = (base speed) * (1 + (tech factor))
base speed = max(0.01, efficiency * speed)
tech factor = (50 + tech) / (200 + tech)

```

### Shell damage

When a ship is shelled, its mobility goes down in exactly the same way that its efficiency goes down (see Info: Damage).

## Sectors

Sectors are charged mobility for the following actions:

### Converting civilians

Each civilian converted costs 0.2 mobility.

### Shooting civilians & uws

The mobility cost to shoot civilians or uws is

```
(number shot + 4) / 5

```

### Enlisting military

The mobility cost for enlisting military depends on what fraction of the civilians present you are enlisting:

```
(new mobility) = (old mobility) * (1 - newmil / civs)

```

### Fighting

See Info: Attacking for the mobility cost of attacking.

### Moving commodities

Sectors move commodities in the "move" and "explore" commands, when "supply" is drawn from them, and when they "deliver" and "distribute" at the update.

Mobility is used from the source sector when moving. Mobility used is a factor of the commodity involved, the amount of the commodity, the types of the sector and dist sector, the efficiency of both, and the cost of the path to the destination sector. When the move is finished, move reports the total mobility used, and the amount of mobility left in the sector.

The exact formula is:

```
mob cost = (amount) * (weight) * (path cost) / (source packing bonus)

```

#### Weight

Each commodity has a weight:

```
bar      50
gun      10
rad       8
dust      5
uw        2
other     1

```

#### Packing Bonus

Some sectors are better at moving certain commodities than others. This ability is known as their packing bonus. These sectors only get these bonuses for moving items "from" them--not for moving items "to" them. If the sector is less than 60% efficient, it doesn't get its packing bonus. Here are the packing bonuses:

```
        warehouse/harbor bank other
mil                    1    1     1
uw                     2    1     1
civ                   10   10    10
bar                    5    4     1
other                 10    1     1

```

#### Path Cost

The path cost is the cumulative mobility cost of moving through each sector in the path. The cost to enter a sector is based on the sector's type and efficiency.

Sectors typically cost 0.4 at 0% efficiency, and 0.2 at 100%. Efficient highways cost less, and mountains cost much more. See "show sect stats" for the exact numbers.

* Road infrastructure, if enabled, allows you to construct roads in sectors and thus decrease their mobility cost by up to 90%.
* Railway infrastructure, if enabled, decreases mobility cost by up to 99%, but only for marching trains.

See Info: improve for more information on improving the infrastructure efficiency ratings of your sectors, and see Info: sinfrastructure for information on showing the infrastructure of your sectors. See Info: Infrastructure for more general information on Infrastructure.

In any case, the sector mobility cost is at least 0.001, except for marching land units, where it is at least 0.02.

#### Update mobility bonus

Commodities get moved at the update through delivery and distribution. All goods moved this way get their mob cost divided by 4 for deliver, and 10 for distribute. Furthermore, commodities distributed into a harbor or warehouse get the warehouse packing bonus (normally, packing bonuses only apply for the type of the source sector and not the type of the destination sector). These two bonuses represent the fact that moving goods through an established distribution network is more efficient.

### Transporting planes or nukes

The weight of a plane is lcm + 2\*hcm. The weight of a nuke is the number of "lbs" it has (from "show nuke stats").

### Shell damage

When a sector is shelled, its mobility goes down in exactly the same way that efficiency goes down (see Info: Damage).

## SEE ALSO

Sectors, Infrastructure, Ships, LandUnits, Planes, Nukes, Transportation