His grandfather (also named Nils Aas) had established a carpentry workshop and water-driven sawmill in Straumen.
Aas' mother Inga Lie was from Telemark and had come to the village in 1928, working for the local parish priest.
Ivar and Inga met and married the same year, and the couple had five children: Marit (1929), Signe (1930), Nils (1933), Aslaug (1935) and Arne (1941).
Nils was educated in the family trade of woodworking from an early age, and his earliest preserved work is a wooden sculpture of Bishop Arne Fjellbu, made when Aas was 16 years old.
[3][4] As a student, Aas had various commercial and industry jobs, particularly over his summers, including a stint at an advertising agency, and another as an assistant at the architectural and planning offices in Steinkjer.
It was in Haukeland's studio that Aas created his own debut work (titled Torso) for the Autumn Exhibition in Oslo.
His most famous work, a statue of King Haakon VII, located in the June 7 Plaza, is made of clay and plaster and cast in bronze.
Other statues by Nils Aas include works based on Grete Waitz and Henrik Ibsen.
He also created a large number of portrait busts, including works modeled on Einar Gerhardsen, Johan Borgen, Arthur Rubinstein, Håkon Bleken, Harald Sæverud, Jakob Weidemann and Rolf Jacobsen.
The most notable piece is a huge circular monument made in birch wood, situated in the centre of the museum.