A monument to Wakefield's finest

She was the daughter of the county surveyor who grew up in a respectable red-brick semi in one of Wakefield's smarter suburbs and went on to become one of the 20th century's most important artists.

A stalwart of the modernist movement, she was also an icon of the left, revered as a feminist survivor of two doomed marriages to powerful men. And she was a mother of four.

Today, Barbara Hepworth's birthplace is putting the finishing touches to a £35m monument to its most illustrious daughter, which it hopes will cement not only the sculptor's place in history but also spark a revival in the fortunes of the city itself.

When it opens to visitors next spring, the Hepworth Wakefield will be the largest purpose-built exhibition space outside London. At the heart of the architect David Chipperfield's uncompromisingly modern structure will be a gift of 44 plasters and prototypes donated by the Hepworth estate, many of which have never been seen before in public.

Removed by the family from her studio in St Ives where she worked in later life, taking centre place will be the full-size prototype of one of her most famous pieces, Winged Figure, which she created for the John Lewis building in London's Oxford Street.

Hepworth said her most profound memories came from her Yorkshire childhood. During drives in her father's car she observed the brick mills and brooding industrial scenes piercing the gentle swellings of the Pennine hills. It was an inspiration shared by another artist with whom she will be forever associated – Henry Moore, the working class miner's son who grew up just a few miles down the road in Castleford and who has his own well-established institute in nearby Leeds.

Moore and Hepworth's work, lives and reputations were closely interwoven. They studied together, shared friends and ideas. At times they were even lovers. But Moore always remained the bigger star of the two.

He was Britain's pre-eminent artistic export of the post-war era. Yet the founders of the gallery hope the new exhibition will help Hepworth step out of his giant shadow once and for all.

"They were extremely close," explained Hepworth Wakefield's director Simon Wallis as he gave The Independent a sneak preview of the building's 1,600 square metres of gallery space. "There was an enormous amount of mutual respect. They moved in the same circles. They came from the same region which gave them a common bond. But their lives were quite different. There is no doubt she would have been affected by the gender politics of the period," he said.

This meant that, despite her serious nature and punishing work ethic, Hepworth as a woman could never rival Moore in the eyes of the art establishment of the time – especially after his triumph at the Venice Biennale in 1948. And that was not the only obstacle she faced.

"She was someone who juggled her artistic life with her domestic responsibilities. It is amazing she achieved on the level that she did considering the pressure she was under. She was married to some very ambitious men," said Mr Wallis.

Hepworth was all too aware of the impact of her relationships. She once observed: "Apart from being a woman, it has not been easy always having great bears breathing down one's neck" She won scholarships to Leeds and the Royal College of Art where Moore was a contemporary, later experimenting with direct carving and travelling extensively through Europe. But her first marriage to fellow sculptor John Skeaping, with whom she had a son, broke down and in 1931 she married the abstract painter Ben Nicholson. Together the couple became part of the European avant-garde, visiting Picasso and Brancusi in their studios. They were close to the Dutch painter Piet Mondrian, helping him find a place to work in London in 1938.

Among her innovations of this period was the introduction of the void into her work, first witnessed in Pierced Form (1931) – a technique which was successfully achieved around the same time by Moore.

The pressures of domesticity arrived in 1934 in the shape of triplets. But Hepworth embraced the role of motherhood and it was to heavily influence her work. She said: "A woman artist is not deprived by cooking and having children, nor by nursing children with measles (even in triplicate) – one is in fact nourished by this rich life, provided one always does some work each day, even in a single half hour, so that the image grows in one's mind."

Hepworth and Nicholson were at the centre of the pre-war Hampstead intellectual community but, five days before the outbreak of war – a time when Moore's reputation was cemented as a war artist in the London underground shelters – the family decamped to the safety of St Ives.

She was to remain in Cornwall until her death in 1975 and it is here that her former Trewyn studio and gardens became home to a Tate collection of her work – making her Britain's only artist to lend her name to two permanent national collections.

But there was tragedy too. She separated from Ben Nicholson in 1951 and two years later her son was Paul was shot down and killed while serving with the RAF in Malaya.

Yet she continued to work, producing some of her most acclaimed art during this period and putting her ideas about public art at the disposal of Britain's post-war planners. In 1964, she unveiled her huge sculpture, Single Form, on the plaza of the United Nation's Secretariat in New York.

It is hoped that the new gallery will attract 150,000 visitors a year, showcasing not only her talents and working techniques but the international movement of which she was such a powerful voice. There will be works by Ben Nicholson, Patrick Heron and Graham Sutherland and major 20th-century loans from Tate and the Arts Council.

But it is also hoped that the futuristic building on the banks of the Calder river will act as a catalyst for change in the perception of her home town of Wakefield.

"It is crucial to be able to understand what effect this part of the world had on both Moore and Hepworth's early development – this is something that both of them reflected on throughout their lives," said Mr Wallis. Both artists' work can also be seen at the Yorkshire Sculpture Park at nearby Bretton Hall.