This is going to depend entirely on how you’d expect those mechanics to play out. For example, a “field” could just mean crops of the same type in an area for some games, but in others you may want an actual structure to them. This could be user defined by just some bounds, or tied to an actor that acts as the manager for the field itself, or a myriad of other possibilities depending on the use case. Do you have a design you’d like to pull off for this mechanic? It’s hard to get into specifics when there’s tons of possible options depending on your plans with it.