Abstract
Non-standard architecture is generally defined by complex double curved systems. We described in this paper three morphogenesis processes. Analytic forms are mainly characterized by regular geometries like cylinders or spheres and portions of these geometric forms are present throughout the history of architecture. Mechanical forms appeared mainly during the second half of the twentieth century, under the impetus of pioneers like Frei Otto: These shapes are guided by an equilibrium condition, the expression of which is known as “form-finding”. Funicular, prestressed and self stressed systems are clearly in this second class. Initiated by the so-called “Bilbao effect” a new trend of double curved systems appeared, characterized by complete free forms that we name flexible forms. The objective is to analyse these classes of forms in relation with parameters of forces, material, technology and structural composition, which are coupled in the conceptual design process. We introduce mainly the coupling between form and structural composition (structural morphology). The last class reveals a lack of links between the parameters, and a complete dislocation of the successive steps of the design process. The evolution from analytical forms to flexible forms, via mechanically-constrained forms is examined in order to determine which constraints designers faced either due to their own choice or for other causes.