Along with the development of new technologies, orchestrating computer-supported collaborative learning (CSCL) has become a topic of discussion because new learning spaces challenge teacher to support collaborative learning in new ways. However, despite the optimistic notions of teachers' orchestration in CSCL situations, there are still no systematic research findings on real-time orchestration. This study is one attempt to fill in the knowledge gap on understanding the differences in knowledge construction processes between settings with and without teachers' real-time orchestration in 3D learning games from a socio-cultural perspective. The aims of the study are twofold. The first aim is to design a scripted 3D learning game to practice inter-professional knowledge construction in a vocational context. The second goal is to determine the main differences in knowledge construction processes in 3D game settings with and without real-time teacher orchestration. Findings provide new insights into what actually happens in collaboration processes within different learning settings. Specifically, students in settings with real-time teacher orchestration used more effort to provide knowledge (especially explaining one's own situation) and less effort for other inputs (in particular, off task discussion). Thus, a scripted 3D game itself guided and helped groups to solve tasks. However, teachers' professional competencies also helped to reduce off task discussions during the 3D game, develop a shared understanding of the tasks' inter-professional nature, and explain activities in a meaningful way. (Contains 3 tables and 2 figures.)