3D printing, also known as additive manufacturing, has become an established technology in many industry sectors for the fabrication of three-dimensional (3D) objects. The layered production of scaled prototypes and smaller series typically use automated computer controlled systems that rely on a-priori designed digital 3D models. General principles for 3D modeling, printing, and finishing exist utilizing the cutting, melting, or softening of paper, polymer, or metal materials. While advantages and limitations of the 3D printing processes require careful review for its final application, the construction industry itself has adopted industrial applications successfully in many examples where, for example, consecutive layers of concrete are combined into a desired structure or form. One of construction?s key challenges though is its need for large scale 3D printing of complex geometric shapes on projects where construction time, cost, and quality are the predominant and determining success criteria. While complexity and scale of the planned structure become available at finer detail during the architectural design process, final fabrication of large scale geometric shapes often fails because of constructability issues. This article introduces conventional construction methods for building large scale and complex geometric structures using on purpose built, automated and robotic 3D printing machines. It therefore contributes the missing link between demanding architectural design that otherwise could only be built at large cost. Commonly known advantages and limitations of existing 3D printing processes, including modeling, printing, and finishing principles are reviewed. Significance of resolution, speed, and quality of materials in 3D printing are explained. Results to an implementation of complex formwork in a major capital construction project are shown. Preliminary benefits and limitations from the perspective of a construction company explain what it takes to advance 3D printing to a field-ready construction method.