Provided is a composition suitable for a process of building a three-dimensional object layer-by-layer by electromagnetic radiation-generated sintering, including at least one poly(aryl-ether-ketone) (PAEK), where the composition has an aromatic ether content of from 0 and 0.4% by mass, based on the total mass of the composition, and an aluminium mass content of lower than 1000 ppm. The composition may be used in process for building an object comprising sintering the composition with electromagnetic radiation. The present invention also includes a three-dimensional object obtained by such a process. A process for preparing the composition is also provided.