In this render by u/dondjersnake on Reddit, the basic Autofactory is depicted as a lightweight circular frame in which materials and machinery are housed, with projects being completed in the center.
ROAMERs can be seen deploying a basic autofactory from the onboard storage of a Heaven vessel in preparation for ramping up production, as imagined by u/dondjersnake.
A production facility, managed by an AMI and maintained by autonomous robots, consisting of 3D printers of various sizes. It is capable of processing raw materials and also of producing any solid physical object (not gasses or liquids) and can work at an atomic level of detail. One of the key features of an auto-factory is that it can produce more 3D printers and ultimately more auto-factories. In later stories, variations on the original idea of auto-factories are also capable of producing biological forms such as plants or animals. They are primarily space-based, but in some situations, a Bob will establish an auto-factory on the surface of a colony planet. It is a continuing theme of the books that a Bob does not control every aspect of an auto-factory's work, leaving the details to the built in AMI; but Bobs often worry over the list and order of jobs they have assigned to the autofactory.