  The Planet Formation Imager (PFI) project aims to image the period of planet
assembly directly, resolving structures as small as a giant planet's Hill
sphere. These images will be required in order to determine the key mechanisms
for planet formation at the time when processes of grain growth, protoplanet
assembly, magnetic fields, disk/planet dynamical interactions and complex
radiative transfer all interact - making some planetary systems habitable and
others inhospitable. We will present the overall vision for the PFI concept,
focusing on the key technologies and requirements that are needed to achieve
the science goals. Based on these key requirements, we will define a cost
envelope range for the design and highlight where the largest uncertainties lie
at this conceptual stage.
