The difference between a physical 3D print and a digital STL file

The word “3D” appears in both listings, which is apparently enough to cause confusion. The useful question is simpler: are you buying an object or the instructions for a printer to make an object?

A physical 3D print

A physical print has already been manufactured. The seller chooses a material, scale, colour, print settings and a level of finishing. It can be packed and shipped. Depending on the item, layer lines may remain visible because they are part of the manufacturing process.

The listing should tell you the delivered dimensions, material, finish and whether the object is decorative or intended for a practical use. Production time may matter when the object is made after ordering.

A digital STL file

An STL is a digital mesh file describing surface geometry. It is not a photograph of a voucher for a later object. No parcel containing the pictured sculpture arrives.

To turn the file into an object, you need access to a compatible 3D printer, suitable material, slicing software and enough experience to choose orientation, layer height, supports and other settings. Post-processing may include removing supports, sanding, filling, priming or painting.

A real example: the same curled figure

Consider a curled-up figure offered in two listings. In the physical listing, the maker prints the object in the stated material and sends that finished print. In the STL listing, the buyer downloads the model and decides how large to print it, how to support it and what material to use, within any licence terms.

The image may show the same basic form, but the transaction is not the same. The digital buyer takes on the manufacturing risk and gains control over scale and printing choices. The physical buyer pays for an object already made to the listed specification.

Check these words before buying

See the separated physical, STL and Historical Editions sections at Cre3Dity.