As a child, he learned to play the violin and he showed great drawing talent from an early age, which was confirmed by one of the famous sculptors of that time, Boris Kalin.
Afterwards, he enrolled at the Academy of Fine Arts and Design in Ljubljana where he studied with professors Boris and Zdenko Kalin.
After a short trip to Paris in 1954, Sotler finished his postgraduate studies at professor Boris Kalin in Ljubljana.
The problem was that sculptures at home were much more in line with modernism so other artist and professionals did not pay much attention to Sotler's art.
Furthermore, studying in Zagreb broke the continuum of sculpturing in his home town, which resulted in his lack of success to receive a public commission.
He also shared his studio with a painter Marjan Dovjak for a couple of years and made an unusual portrait of the artist during that time.
In May 1958, he married Sonja, née Beretič, from Šmarjeta pri Novem mestu and in October of the same year they got a daughter Alenka Sottler, who has become one of the leading illustrators in the world.
Many drawings and small statues were created every day, but most of them ended up in trash due to the artist's severe self-criticism.