The Planet Formation Imager (PFI) is a near- and mid-infrared interferometer project with the driving sciencegoal of imaging directly the key stages of planet formation, including the young proto-planets themselves. Here,we will present an update on the work of the Science Working Group (SWG), including new simulations of duststructures during the assembly phase of planet formation and quantitative detection efficiencies for accretingand non-accreting young exoplanets as a function of mass and age. We use these results to motivate tworeference PFI designs consisting of a) twelve 3 m telescopes with a maximum baseline of 1.2 km focused onyoung exoplanet imaging and b) twelve 8 m telescopes optimized for a wider range of young exoplanets andprotoplanetary disk imaging out to the 150 K H2O ice line. Armed with 4×8 m telescopes, the ESO/VLTI canalready detect young exoplanets in principle and projects such as MATISSE, Hi-5 and Heimdallr are important PFI pathfinders to make this possible. We also discuss the state of technology development needed to makePFI more affordable, including progress towards new designs for inexpensive, small field-of-view, large aperturetelescopes and prospects for Cubesat-based space interferometry< Leer menos