Kaita Mono wo Jittaika suru Nouryoku de Motenai Ore ga Harem Seikatsu

Kagehiko was attending art school, feeling jealous of god-tier artists and frustrated with his own lack of improvement. One day, while brooding on a railway overpass, he bumps into a passing old man and... falls. When he wakes up... he realizes he's been granted "the ability to materialize what he draws." And then... starting with a dramatic reunion with Pastel, a beautiful girl he drew in his childhood, his life begins to turn around...

(Source: Takeshobo, translated)