Explore an in-depth lecture on the modelling of soft-particle production in QCD event generators, focusing on the transition from proton-proton (pp) to nucleus-nucleus (AA) collisions. Delve into advanced concepts and techniques used in particle physics simulations, examining how these models handle the complexities of different collision types. Gain insights into the challenges and recent developments in accurately representing soft-particle production across various collision scenarios, enhancing your understanding of QCD event generation and its applications in high-energy physics research.