It's grease pencil as others have mentioned, Jama Jurabaev talked a bit about this kind of workflow in a Blendconf talk last year[1]. I believe that griffon is

It's grease pencil as others have mentioned, Jama Jurabaev talked a bit about this kind of workflow in a Blendconf talk last year[1]. I believe that griffon is this[2] piece of concept art he did for the Fantastic Beasts movie. [1] https://www.youtube.com/watch?v=UpcKPJTmqSI&t=935 https://www.youtube.com/watch?v=UpcKPJTmqSI&t=935 [2] https://www.artstation.com/artwork/oO2r0q https://www.artstation.com/artwork/oO2r0q