An art gallery is a space in which people and art can interact. Inside, the art is the star, not the shed. You need large areas of flat vertical wallspace, high enough for large works but not so high, ideally lit by natural daylight through Northlight roof glazing. You need to restrict the UV light that damages pigments, and control temperature and humidity within fairly tight limits. With people moving in and out, breathing, and opening and closing external doors, the environmental conditioning needs to be quite clever. You also want to minimise solar heating effects and cooling shocks. In plan, an oblong or rectangular gallery layout maximises wall space to floor area and volume. A decent architect will achieve all this internally, and - here's the skill - produce a building that looks good from the outside.
Viñoly seems to have ignored every single design rule in producing Colchester's 'Firstsite' - from here on to be referred to as 'Viñoly's Crapsite'. Here's what the Guardian's Rowan Moore thinks;
A great wall, which might be a nice place to put pictures, not only curves but also slopes outwards as it rises. Other gallery walls also curve or are made of glass. Some spaces are very high, to no purpose. On the rare occasions when a plain, blank piece of wall presents itself, it usually gets punctured by doors. Firstsite will show temporary exhibitions of contemporary art, and say that "art practice has changed so much in recent years; artists are creating work in so many different media", so the idea seems to be that flat surfaces for fuddy-duddy paintings would not be needed as much and there would be installations and sculptures instead. Except the slope of the walls narrows the space at ground level, precisely where you would most want room to circulate around large objects. Oh well, perhaps they can project some video pieces. Or would, if a profusion of windows at many levels did not make much of it almost impossible to black out.Colchester Council would be better off turning it into a 'fun pool' with flumes and slides and charging £10 a time to try and recoup some of the bloated £28m of public money that Viñoly has managed to waste on this truly awful excrescence.