I think the issue of GN Field deployment is tied to how well a unit can manipulate GN particles. We only ever see the Exia and Dynames deploy Fields when docked with the Arms, whose wings double as massive clavicle antennae; as well, the Kyrios's nosecone was deployed whenever it created a Field, and the nosecone had two extra antennae on it. The Alvaron had its great big wings that moved during Field deployment, too, and the Seravee has the Seraphim's very large clavicle antennae.Meteoid wrote:Which is fine since they won't be doing any fighting in re-entry. Also for Kyrios to project it's GN-Field it was semi transformed (the Nosecone was up) I would guess the Gundams don't have a problem with the amount of particles but emitting them is the issue if they want to use it in combat. Virtue has it's chunky emitters, Kyrios' nose serves as an emitter and the Exia and Dynames' Emitters are the GN-Arms. In re-entry I think they just spread huge amount of particles from the drive and the condensers and they act as a "quasi-GN Field" that is good enough for re-entry but wouldn't hold together in combat.
We've also seen the Eins, Drei, and GN-X variants use small, one-way Fields, and they have a noticeable lack of coordinating equipment. The 00 could create a one-way barrier on its own, but the 00-Raiser could create an omnidirectional Field once it had the addition of the 0-Raiser's four large antennae.