London visual effects companies Double Negative and Framestore worked directly with Cuarón from script to post production, developing effects and creating "environments and shots that wouldn't otherwise be possible".
As empresas de efectos visuais Double Negative e Framestore traballaron directamente con Cuarón dende o guión até a post-produción, desenvolvendo efectos e creando "escenarios e escenas que doutro xeito non serían posibles".