Smooth surface finish is one of the most required aspects of a 3D print, but it’s not only an aesthetic need: it happens very often that smoothness is a functional requirement for the end users. Applications in which smoothness may be a functional requirement include mating parts, moving parts, stress/load-bearing surfaces, etc. Below you will find the list of the 3 key factors for ensuring smoothness of your finished 3D printed parts, suggested by the engineers from [Xometry](https://xometry.eu/en/), the marketplace for on-demand 3D printing with more than 2.000 manufacturers in Europe.