There have been no objections to allowing 3D printing following my lengthy post on the matter - unless there are any strong arguments against, by this evening (or in case of work-overload, by tomorrow noon) I will close the rules allowing any amount of 3D printing, with the obvious proviso that although there might not be physical model bits to show, anyone including it extensively still adheres to the guidelines and posts about the design process and includes images (as would be the case for any other construction approach).