Recently, scholars highlighted the crucial role played by drawings in students' modelling performance. Nevertheless, the correlation between the use of drawings and modelling performance cannot be extended when complex modelling activities are considered. In this work, we focus on the students' drawing activities when dealing with a complex geometry problem. In particular, the paper reports an exploratory case from 11-grade students exposed to a realistic scenario from the sport context, on which they have worked for 4 hours. The analysed data, which focus on one of the class discussions, show that an important aspect for drawings to help students in the mathematical modelling process is that drawings must be shared among students. In this way, students can put into play different strategies for connecting both solution-relevant and non solution-relevant drawing elements, such as understanding, coordinating, contrasting and integrating, that help them in proceeding throughout the mathematical modelling process.