...is there a reason why they can't do the printability check (processing) for "all" the parts in an order at the "before" submitting any for production? The parts I have uploaded to date are just individual components that will go together to form a larger model. In some cases these components are themselves split into two or more parts to aid in construction, save on material and reduce weight, variously. My orders will generally include a full set of such parts to support the completion of a larger model. However, Shapeways' approach has been to review, process and send to production the parts individually or in small groups. This has meant that some parts go forward into production while others are rejected. Not a major issue if the rejected parts are easy and quick to fix but it becomes a real problem if there are repeated failures since having only half the parts is pointless if I need all to create the model. If the processing were complete on "all" of the parts "before" any were submitted for production and a report on printability provided to the customer that would give us the chance to determine whether it was worth printing any at all at that time. For me this would reduce the risk of ending up with only a few of the pieces I need and avoid the hassle of repeated refunds and re-orders. Indeed, I would have thought the latter might prove just as helpful to Shapeways?
The only alternative to the above is that I effectively upload all of my parts as one, with the parts connected to each other by a 'sprue' in the same way that traditional injection molded kits are usually presented. This would upload as a single file and would be reviewed/approved/rejected as such. Although this would reduce the risk of having half a kit produced it still seems a rather cumbersome approach. Even if the sprue meets the overall size requirements of Shapeways the shape and layout might surely reduce Shapeways' options to economise by combining parts from different orders and that's before considering the waste of plastic to create the sprue. Just a thought ;)