At first glimpse the Hepworth Wakefield, set at the headland of the River Calder with water on two sides, enjoys high visibility from all sides. The setting, although a conservation area, was derelict and inaccessible for many years, so the new museum with its grey pigmented concrete facades and roof is all the more of a surprise to witness. “There are no fronts and backs: we were very careful to avoid that”, says Chipperfield of the building, which is hub of ten individually sized, discret but connected, trapezoidal blocks. These house five galleries showcasing the work of the famous Yorkshire-born sculptor Barbara Hepworth, a gallery of works on paper from the 18th and 19th centuries, a small gallery of 20th century British artists and four galleries with 650 m2 of temporary exhibition space for contemporary multi-media works. The facades’ sculptural tactility and sense of assemblage echoes the powerful forms of Hepworth’s work. Chipperfield is not a fan of flowing gallery spaces, and wanted to make a definite room structure for the museum, which is the largest purpose-built art gallery to open in the UK since the Hayward on London’s Southbank in 1968. As a volume it is quite big - 5000 m2 - and he wanted to see if he could make it “a fragmented building, a series of buildings linked together, rather than one big building trying to disguise itself.” It feels appropriate for the internal room structure to express itself on the outside. Chipperfield’s solution gives the museum a certain personality, with the blocks breaking down any notion of a singular form, and the service door at the rear becoming part of the “sculpture” of the whole building. The structure was made with in-situ cast concrete, with the load-bearing façade made using an innovative technique to allow it to stand partly in the water facing the weir and give a very clear, monolithic form. All the windows are flush with the façade so that there are no recesses interrupting the lines of the building, which adds to the strength of the family of forms. A long bridge on the north west side leads into the entrance foyer which has a functionalist atmosphere, lacking in grand gestures but clearly laid out with easy access to the bookshop, café bar, auditorium, studios and cloakroom, all with views of the building. The architecture encourages the visitor to hasten to the galleries: you go up towards the light, and Chipperfield’s design privileges access to daylight in a masterly and varied way. The geometry of the cluster of galleries, which are all on an upper floor, is like a three-dimensional jigsaw, and each of the ten rooms, none of which are rectangular, are within a metre of roughly the 3-6 high metres, which adds to the sense of diversity. “We wanted to get variation into the plan without it being forced”, says Chipperfield. He has been careful how the light is brought in, with light slots in running the full width of the ceiling of each gallery at one end of the space so it does not need much filtering, which gives the visitor a sense of the changing atmosphere of the sky beyond. The pitching of the roofs varies from block to block so that each light slot admits and diffuses light in the best way for each gallery, and the results are experientially extremely satisfying and make people want to linger. This approach to scaling combined with the floor to ceiling window apertures giving glimpses of the water, the weir, nature and the old brickwork of the next door building that are created from one space to the next, makes the galleries feel very natural, yet none of this detracts from the intimate spatial experience within each. “Art has no greater enemy than the architect”, said the eminent critic David Sylvester, yet at the Hepworth the individualised pitching of the roofs, shifting of the walls, their slight suspension above the ground and wide doorways gives the sensation of very interesting diagonals to take in, instead of the more rigid sequencing of many galleries. Chipperfield has matched the subject of the gallery to the design, with the gallery of Hepworth’s casts (maquettes used to make the work) the one in the complex with the most exposure and daylight, as they are the least fragile of the objects. He and his team made a hundred models to work out what size things should be, and get enough difference between one roof corner and another, which made for a complex process to get to the final design. Manipulating the volumes was also “a very sculptural process”: at times there were twenty four, at others five volumes. The architect did not want the complexity to be arrived at too wilfully, but it to be a rigorous concept embodying “moments of serendipity” for the visitor. Well aware of how unsatisfactory spaces can be when not under control, Chipperfield says that making everything look reduced, ‘you have to work really hard.’ He is also acutely aware that museums have changed, and that the ambition is to draw new audiences. His treatment of the ground floor is in fact a classic 19th century museum approach, with facilities arranged and the staircase leading to the works above, but easing more space for the now critical public amenities all museums need to have than would have been conceived in the 19th century. The museum is part of a strategic regeneration of the city of Wakefield, giving it a “certain authority”, a focus which begins in the new riverside play area in the gallery garden. But the dignity with which this process is being carried out is first represented in the galleries, which are not hermetic spaces but have a sympathetic connection with the world surrounding them.