Building 3D-Printed + Mass Manufactured Homes Is 50% Faster, Produces 99% Less Waste, And Can Be 80% Automated The world needs two billion new homes in the next 80 years, the World Economic Forum said in 2018. Perhaps the answer is to reinvent construction with a mix of pre-fabrication, 3D printing, automation, plus a heft dose of ZNE, or Zero Net Energy: homes that generate all the power they need.