In the research project presented in this paper we investigate the architectonic and constructive potential of additive digital fabrication in timber construction through robotic processes as well as the relation of functional requirements of an exterior wooden wall to design. Form finding through performance analysis is of great interest for architects. With advanced digital fabrication technologies at hand it is possible to produce articulate building elements. This can be exploited to analyze and transform performance criteria into architectural expression. We argue that functional requirements and formal characteristics are interdependent. To allow performance criteria drive the generative parameters of design, custom software tools need to be developed which impart physical aspects of building elements to digital design models.