NOTE: Planets.nu uses two different systems to drive priority builds. Some games use this, and the others use the newer Production Queue system. Check to make sure you're in a PBP (Priority Build Points) game before going on.
The PBP system was used in the original VGA Planets as a way of rewarding players for successful combat. When a starship was destroyed in combat, the winner of the battle received PBPs. The greater the hull mass of the destroyed starship, the more PBPs are received.
In system-generated games, there is a hard starship limit of 500 total starships that can be built. This limit can be changed in Custom games. This limit is imposed to prevent the game from becoming too complex and to encourage players to begin fighting in order to build more starships. Once the starship limit has been hit in a game it is not possible to continue to build starships.
In the early game (before the number of starships is within 50 of the starship limit), every starbase with a build queued will have that starship built. Builds will not consume any PBPs unless they are constructed on starbases using a pbN code. This code is not generally needed except to get both a build and a clone out of a starbase.
In those turns when the starship count is within 50 of the starship limit, but the limit has not yet been reached, every starbase with a build queued will have that starship built, but all builds will consume PBPs until the player has fewer than 21 points. Bases with a pbN code will build first and will consume PBPs until, again, the player has fewer than 21 points. At these bases, it is possible to both priority-build and clone a ship during the same turn. (NOTE: Some doubt has been raised with regard to the validity of this last statement in games that have been created recently.)
After the starship limit has been reached, normal cloning will be disabled and only priority builds (see below) will be permitted. If at any time the ship limit is not again reached by priority builds, a standard build subphase will occur.
In the first step, players with 21 or more PBPs will perform Priority Builds. For each available ship slot, the player with the greatest number of PBPs will get a starship build.
If that player has a starbase with a pbN Friendly Code, the starbase with the lowest pbN Friendly Code (i.e. pb1 then pb2 then pb3, etc.) will receive a build. If that player does not have a starbase with a pbN Friendly Code, the next starbase in the build order with a build queued that belongs to that player will receive the build (the build queue will not advance).
All Priority Builds will consume PBPs.
This above process will be performed as long as the starship limit is not reached and there are still players with 21 or more PBPs and a starbase with a queued build.
If, after the Priority Builds are complete, there are fewer starships than the starship limit, standard builds will be performed until the starship limit is hit. These will occur at starbases in sequence, in ascending order by planetary ID number, and the position in sequence will be remembered between turns. Priority builds which occur at a starbase scheduled for a standard build during that build phase will not bypass or circumvent the build queue. Note: All ship cloning takes place during this build subphase.
On those builds which consume PBPs, 1 PBP will be consumed for each 50 KT (or fraction thereof) of starship hull mass.
Priority Build Points can be earned in several ways:
For more detailed information about the specific timing of shipbuilding, please refer to the page on The Host Order Of Shipbuilding.