The concept of tomorrow's towns and cities will be based on new social, economic and technological ideals focused on improving the quality of life. To attain this objective, architects and engineers of today must improve the quality of buildings and establish new principles of building conception. The quality of interior space and the impact of a building on its surroundings depends strongly on the physical interface that separates the outer environment from the inner building space. The conception and realisation of this interface (the envelope) are, therefore, of prime importance.