We investigate how the creativity support tool combinFormation supports the creativity-oriented course, The Design Process, by representing collections as compositions. Undergraduate students in The Design Process are charged with working in interdisciplinary teams to develop new inventions. combinFormation is a mixed-initiative system that integrates browsing, searching, representing, manipulating, and collecting digital information resources, using the form of the visual composition space. Students use the composition space to develop collections of prior work that support their creative processes of developing new inventions. A quantitative study shows the overall effect of mixed-initiative composition on the performance of student groups on creative projects. To understand the mechanisms of situated creativity support, we follow-up with case-study interviews of two project teams. We develop the frameworks of distributed creative cognition and situated creative learning to analyse the interview data. We find that the mixed-initiative capabilities of procedural generation and human manipulability of visual information representations in the composition space support distributed creative cognition and situated creative learning.