It could have been a rectangular prism whose length measures fortyone meters and a half, whose width measures thirtythree meters, and whose height measures twentyfive meters. It could have been, if the projection had ended in the trace of a pure rule. It could have been almost the same: three elevated plans, each formed by three rectangular exhibitions rooms, placed at two consecutive faces and connected by ramps that run on the two other faces. Then, a fourstoryhigh atrium rises between circulations and rooms, creating a diagonal symmetry inside the building.
But the building is not just a rule. It is mainly the materialization of a set of variations. The ramps of the prime rule, with an extension of fortynine meters and fiftyeight centimeters divided into two perpendicular segments on each level, would need either a slope of eleven and a tenth percent or an increase of thirteen meters and thirtynine centimeters in its extension with a slope of eight point seventythree percent in order to achieve the five meters and a half difference between floors. So the obvious choice, which implies a first set of spatialformal variations on the building, is for the increase in the extent of the ramp: the first of a set of variations that will determine the visual identity of the building. The order of the corner of the exhibition rooms is maintained; the order of the corner of the ramps is metamorphosed. The original perimeter still remains materialized at the two other corners, determined by the opposite diagonal of the rectangle, which receives the two staircases of the building.
By maintaining the original perimeter of the building, the original position of the ramps and the original start and end points of the slopes, the only spatialformal possibility for the ramps to achieve their needed extent is the irruption of outdoor and/or indoor ledges. The building materializes both possibilities. The original ramps are duplicated into new bifurcated ones: an external rectilinear one and an internal curvilinear one. Each flight of the ramps is formed by three segments: three linear segments in the first case and three arcs in the second. Each flight reaches the same height, the half of the difference between consecutive floors, two meters and seventyfive centimeters, and therefore has the same total length as the sum of the horizontal components of its slopes. Between the three curvilinear ramps and the three rectilinear ramps a brand new atrium rises: an outside and open one, whose ceiling is the very sky.
Connecting the floors is always a flight comprised of a curvilinear ramp and another comprised of a rectilinear one: the ascending or descending path intercalates both kinds of ramp. But visually each type is combined as creating a false continuity: inside, only the ascension of the three flights of curvilinear ramp is seen; outside, mainly the three flights of rectilinear ramp. The spatial reality of the building integrates; the formal reality isolates.
The new perimeter of the building is now materialized by a curve formed by a central convex arc and two side concave arcs connected by tangent lines. It emphasizes the trace of the curvilinear ramp, but slightly modifies it, in such a way that these ramps subtly appear in the façade. In front of and detached from this new curved surface, the visually continuous three flights of rectilinear ramp surround the open atrium. The curvilinear ramps separate inside and outside, they are the only elements that break the mainly orthogonal character of the building.
From a twosegment ramp surrounding a closed atrium, two threesegment ramps surrounding two atriums, a closed one and an opened one. That is the variation. From a prism, a rock. Thus is the materialization of the building.
This article was written by Igor Fracalossi, Articles and Classics Editor for ArchDaily Brasil.
 Alvaro Siza

1350.0 sqm

2003