Purpose: This paper aims to study the visibilization of learning in the context of developing a new collaborative practice, knotworking, in building design. The case under study describes the process of learning from the initiation of knotworking to its experimentation. The implementation of new building information modeling tools acted as an impetus for this development. Design/Methodology/Approach: The research is based on activity-theoretically oriented ethnographic research. The four analytical steps created by Engeström (1999) for analyzing the expansive visibilization of learning are applied in the analysis. Findings: The envisioning of the idea of knotworking involved the first and the second steps of visibilization. First, a flowchart made the ideal process of design visible and triggered a discussion on the problems and requirements emerging in the project members' work. Second, an idea for a new type of collaboration was introduced as a solution to these problems and requirements. Planning the knotworking experiment and explicating the associated design instruments involved the third step of expansive visibilization. The fourth step of visibilization took place during the experiment of knotworking in a design project. Practical Implications: Two other knotworking projects have already been conducted, and plans have been made to commercialize knotworking in building design. New technical tools have been developed for energy calculation and the comparison of alternative design requirements. Social Implications: Knotworking can improve the collaboration between designers with positive implications on the quality of a building design process. Originality/Value: Development and learning are studied as a longitudinal process in the construction industry.