Application of structural optimization to transmission tower design is facilitated since major costs, including material, transportation, construction and maintenance, are directly proportional to the mass. Transmission towers are unique civil structures since they are often free from aesthetic considerations making the results of structural optimization less susceptible to subjective assessments. In this paper, shape annealing, a computational design technique, is applied to the optimally directed re-design of transmission towers. Shape annealing has been presented previously as an effective method for the generation of conventional and innovative discrete structures. So far, the method has been targeted at the conceptual design stage. This paper focuses on the re-design of existing full-scale transmission towers in collaboration with Énergie Ouest Suisse (EOS) in Lausanne, Switzerland. The purpose of this paper is to present the challenges and results of applying shape annealing to a highly constrained industrial application as well as the modifications that were needed. This application resulted in suggestions for improving the existing design and insights about practical application of the method to create a system for transmission tower design.