A vehicle replicator is a large-scale replicator able to quickly “create any means of transport,” including shuttlecraft. Typically housed in the shuttlebay, the vehicle replicator has multiple replicator arms and worked by assembling individual components into the vehicle as they are built up from replicator arms. As vehicles are complex items, the build takes time (audio updates are given for each ten percent of completion) and once assembled, the computer will run checks and diagnostics to ensure a correct build before releasing it for use.
Though a natural outgrowth of industrial replicators, due to the complexity and design requirements of vehicles rated for sentient beings the vehicle replicator wasn’t developed until the later part of the 24th century. However, given their utility, especially for deep space exploration vessels, most late 24th century starships with capacity for at least four shuttles may be assumed to have one. Also, older ships capable of hosting industrial replicators may be refitted to include one, but at the cost of shuttle bay space, both for the replicator and the size of the space will limit the size of the vehicles that can be replicated.
Other considerations also delayed the widespread implementation of the technology. In particular, power requirements must be taken into account. Converting that much energy to mass, or mass to different mass, takes a great deal of energy – a fact which must be taken into account before activating the replicator. The drain on power can, for instance, prevent shields from being established. So, while the vehicle replicator can provide additional emergency transport in an emergency, in a combat situation using it may require a to be made to give up weapons or shields (or burn all other reserves in expectation of abandoning ship).
Approved designs are preprogrammed, as well as diagnostics for verifying the build prior to release. It should be noted that only vehicle designs reviewed and approved by Starfleet Engineering are available for replication. And because the Engineering Corps understands the temptation to tinker, safety protocols are embedded to prevent that. It is recognized that motivated individuals may find ways around these, but such action must be justified and will be subject to official inquiry and review by Starfleet Corps of Engineers Command.