After reading Shapeways' recent post discussing their new design rules for stainless steel prints, we thought we should weigh in. Shapeways has gone as far as developing a dedicated "Design Rule Repository. What's in it? According to their post:
This is a subsection of the website dedicated to design rules. Going forward, the blog and forum will be used to report on changes to this repository. It should not be considered a reliable source for listing the rules; the official rules will be found (or linked to) in the design rule section of the web page.
Anyone who does 3D printing realizes this sort of thing is required, because there is no such thing as a "universal printer" that can print any arbitrary shape. There are peculiarities of object geometry, often in combination with the materials used, that can prevent successful prints on any type of 3D printer.
However, the same scenario might work well on a different kind of printer or perhaps with a different material. Design rules are helpful because they can quickly indicate whether a given object is printable or not, or even better, influence the object's design towards a shape that will actually print.
So who needs design rules? Everyone, it seems.