when im allowed to decon an armory to build it somewhere else. Or an reactor.
Build the new armory first then decon the old, on regular BP servers you should only ever have ONE armory maybe TWO if you think aliens will kill the original during SD. (ie. if maras have consistently jumped the d and taken out the armory during gametime before sd, it's a good bet you'll want a second armory.)
Reactor should not be moved unless you have the following:
1) Guards that can aim and defend you while you setup the new base location
2) A second builder that will either build the enw reactor after you decon, or will let you build after he/she decons.
3) You know for a fact the team is ready to move and there are no aliens waiting just outside the range of your turrets/defenses (turrets make an audible noise when powered, unpowered the silence is a dead give away)
Whats the difference between an tesla generator and an normal turret.
Teslas cannot be jumped over, do slightly more damage (at a lower rate of fire), has 4x normal knockback, are more fragile than a turret, and require a second structure to even work. Generally teslas are a support defense and should NEVER be completely converted to.
How many Spawns i should build?
On normal build point servers the bare minimum you want is two, though sometimes you may want three. On obscene player count/bp servers like SST you will likely end up building 4+. The one exception is Aliens on transit. Often humans will ravage alien base early on this map forcing grangers to do what is known as 'egg spamming', by this it means placing the OM anywhere just so the 5+ grangers can place eggs all over the map. This is typically done at S2 and makes it near impossible for humans to finish aliens off before aliens reach S3, once you have tyrants pushing humans back you'll go back to normal build structures.
How i react on new envolves from the aliens?
S1/S2 - you'll want a turret or turrets around your react/armory to keep maras and goons out of base
S3 - You'll want to focus your defense into choke points that are not easily sniped by adv goons. This is primarily to deal with tyrants. Teslas should be built to keep maras and goons from jumping over forward d and into your base. However this is still possible so you'll want to be careful.
And what im doing the rest of my time? Is a builder just a builder or only when the human team ist in defence?
As builder you'll be using Right mouse button to repair damaged structures and repalcing what aliens destroy. Similarly you should be observing your defenses and spot checking for weaknesses, ie. if a mara can jump past your d you might want to reposition the defenses to make it less easy to do so. Or if a tyrant can charge between your teslas and into the base you might want to put them closer together.
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All in all watch some of your favourite servers builders. Watch where they build and wether it works or not. You'll eventually get an idea before hand what will let your team survive longer or end the map quickly.