What are weapon groups?
Weapon groups are a simple yet very effective way of rapidly switching between various weapon activation combinations.
Why are they useful?
Fighters and Bombers
Their main use lies in reducing the energy cost of firing in the following way:
When the target's shield is up, people mostly choose to use a weapons group which contains all the guns at their disposal, except missiles, torpedos, Mini Razors, Nuclear Mines and other similar gadgets. However, when the target's shield goes down, people mostly choose to activate a group containing only the weapons which are effective against hull, aka hullbusters, and deactivate anti-shield weapons, aka shieldbusters. This way you can significantly save up on energy and lose little to none on damage achieved.
They are also very useful for firing weapons such as Cruise Disruptors, Mines, Various Missiles, and Mini Razors, especially with the Mini Razor which requires a good aim, and is therefore best fired when it's activated so the targeting computer can calculate it's lower trajectory speed in. The same example, if not even more, goes for the Supernova Antimatter Cannon which is a bomber weapon very difficult to aim, and which also spends an enormous amount of power, and is therefore recommended to be kept in one separate weapons group.
An additional use for grouped weapons is used by some players to get around some weapons slow refire rates. By assigning half your guns to one weapon group, and using the "fire group X" to shoot only these weapons, then using the standard group to fire all standard weapons, you can easily get the two groups to fire in sequence, thus achieving a higher amount of independant shots, with fewer guns firing at the same time. Effectively, you're turning for instance 4 2.0 refire weapons into 2 4.0 refire ones. Weapons such as the Liberty Magma Hammer or the Rheinland Firekiss series lend themselves to this technique. Gunboat and bigger capital ships can use this same technique, but it is less useful in capital fights.
For capital ships, the main use of weapon groups is grouping of your weapons which have different flight speeds. If the flight speeds of your weapons differ by too much, you won't be able to hit practically anything. So for example, if you have a mixture of Cerberuses and Solarises it is best to keep the two in separate groups, because they differ by hundreds of m/s in flight speed.
Weapon groups are also very useful for grouping of special weapons such as the Cruise Disruptor, Heavy Mortar, Light Mortar, Battle Razor, Pulse Cannon, etc. Experimentation is recommended.
How do I set up weapon groups?
Well, it is rather simple if you follow the instructions. First, make sure to have your weapon activation tab open like this:
Weapons HUD Tab
This is needed to have a good overview of the setting up process. You'll understand later. Now, do the following:
Press F1 -- > Options -- > Controls -- > User Interface. A.K.A.
In there you will find keys such as: Activate Weapon Group 1 Activate Weapon Group 2 Etc. Depending on how many weapon groups you require, map the corresponding number of weapon group activation keys, from 1 and further, to a maximum of 6. In the image they've already been mapped to certain keys, but you don't have to use those if you do not wish. Alternatively, just use the 1, 2, 3, etc. keys.
Now, after mapping the desired number of keys, exit the options screen and once more pay attention to the Weapons Tab on your HUD. After pressing the key of the weapons group you wish to set up, make the desired weapons green by clicking on them if they already aren't, or just leaving them be if they already are, and the undesired ones grey/white, by ignoring them if they are already so, or clicking them if they are green.
Repeat the process as many times as you wish, depending on how many weapon groups you need.