One of the challenges in today's society is to satisfy the growing need for creativity and innovation, especially in design contexts, where designers have to come up with products that are both new and adapted to their users. Although designers' professional experience is crucial, we consider that their creative skills can be nurtured in design schools. We therefore explored the effects of two types of design project-oriented methods, which were operationalized as specific courses offered to design students. As our objective was to determine the impact of this training on creativity, we looked at both the students' evocation processes and their creative output. In the first of two studies, 32 design students had to perform the same creative design task, but half of them received training based on brainstorming principles and the other half training based on constraint management. Here, we focused our analysis on the students' evocation processes. In the second study, we asked 16 teachers specializing in creative activities to assess the students' output according to different criteria. These two studies showed that the two types of training had a differential impact and allowed us to explore relationships between constraints and ideas in creative design.