In his book "The Price of Everything", Eduardo Porter writes that "Everything has a price, but it isn't always obvious what that price is". That is true also for 3D-printed objects. Until a few years ago, rapid prototyping services were always accompanied by the consultancy of an expert and quotes would implicitly include that into the price for a 3D-print. Companies like Shapeways and Sculpteo are making us accustomed to highly standardized web-based 3D-print services for which human interaction is minimized to offer competitive prices. Figuring out the right price formula is not an easy task and even Shapeways tweaked its price models a couple of times since it started operating.3D-print prices can be chosen to depend on a number of variables: amount of print material, amount of support material, machine space and machine time being the most common ones. Accurately quoting prints for some printers, like, for example, the ProJet 660, can involve the estimation of the binder, dye and infiltrant use on top of machine time and print material. For some technologies, like SLS, the support material does not noticeably affect the print costs whereas for others, namely FDM, the support material represents a non-negligible cost component.Quoting 3D-prints offline is slow but straightforward. The software bundled with the printers can estimate material use and print time, which can then be inputted into a spreadsheet to compute the print quote. Most 3D printing bureaus still work this way, but the global success of e-commerce clearly shows that web-based online pricing is what consumers prefer. Slicing or toolpath generation is often too slow to be used to generate quotes online, where waiting times should be as short as possible. For this reason, at Fabnami we develop fast and accurate algorithms that compute material use and machine time based solely on the geometrical and topological features of 3D-meshes, without the need to use slicing software.The most challenging class of algorithms we developed is closely related to the computation of the support material. The volume of the support material heavily depends on the orientation of the model within the printer bed. Also, some companies developed enhanced methods to generate the support material and reduce print costs, like the trademarked Stratasys SMART support, which, according to Stratasys' press release "works similar to classic arch design in architecture, in which columns support layers of bricks that get progressively wider, so that the narrow columns can support a structure much wider and heavier at the top".Since its first release, Fabnami offers the possibility to compute the "shadow" support material volume and, optionally, to minimize its volume by optimally rotating in real-time the 3D-meshes. In this way, Fabnami computes accurate online quotes without having to resort to approximations. Since mid-February 2015 Fabnami also offers the possibility to estimate the use of the support material generated by Stratasys' SMART methods, which opens up the possibility for Stratasys' printers owners to offer their services online.Is so much accuracy really necessary? Companies like 3DHubs presently price prints by print-material volume only and they have been so far successful. The need for accuracy depends on the business volume and so on the number of prints. Large 3D-printing bureaus can quote prints based on approximate estimations, because errors are averaged-out. Small companies instead do not enjoy the possibility to rely on large-number statistics and need accurate pricing for single prints, not only on average. That's why we devoted so much time and resources to the design and development of proprietary algorithms, based on which our servers quote thousands of 3D-prints each month.
