The competition launched by the IMS in 2004 envisaged a building with an L-shaped floor plan and a deep bay. The geometry precluded any arrangement that would work with the climate in a favorable way: the deep bay forced to work with non-through dwellings and the L-shaped arrangement generated self-arrowing shadows. Only 15% of the dwellings would have a suitable orientation and 5% the possibility of cross ventilation.

The building's shape was modified to integrate the building into the urban coherence and to take advantage of the great energy potential of the south orientation in a rigorous and simple manner.

By its design, the Solar Hemicycle follows the sun. The envelope is conceived as a large solar collector during the winter and an immense umbraculum in summer. The constructive solution of the envelope allows for flexible layouts, different levels of openness or concealment.