>How does it accomplish that? That was definitely one of my bigger problems with BFG.
There are two or three big "selling point" mechanics for DFC, and are as follows.
"range =scan+signature+spikes"
"movement and special orders"
"orbital layers"
>range =scan+signature+spikes
In essence, every weapon except for Close Action weapons (more on those later) has potentially infinite range. The current range of a weapon is determined by the Scan of the ship that is attacking, and the Signature of the ship that is being attacked.
Let us imagine an example where a ship with a scan of 6" has two potential targets; a battleship with a signature of 12" that is 18" away, and a frigate with a signature of 3" that is 12" away.
If our ship were to attack the battleship, it's range would be scan+signature, which is 6"+12" =18"; the enemy ship is just within range.
If our ship were to attack the frigate, it's range would be 6"+3" =9", which is 3" short from where the frigate actually is; our ship cannot attack the frigate.
As you can see, absolute distance means less than relative distance, based on how big of a signature the target has.
In addition, a ship is ALWAYS targetable if it's within your scan range, even if it's signature is 0".
Spikes are status effects that modify the size of a signature, coming in either a minor (+6") or major (+12") form. These are caused by undergroing special orders such as firing all weapons, going max thrust, holding position, and so forth.
Fluffwise, this can be explained as follows; your scan range is the range at which your scanners can overpower any and all enemy attempts at cloaking, stealth, spoofing, or what have you. If an enemy's signature is big enough, even though it's outside your scanners optimal range, you can secure suitable fire control to be reasonably sure at hitting the enemy ship; the enemy ship having spikes on makes it "light up", allowing your sensors to get a lock at longer ranges.