This book introduces DAVID (Draw A Vensim Initial Draft), a cutting-edge tool that takes the capabilities of ChatGPT a step further. DAVID transforms a textual description of a problem into a fully functional Vensim model. By integrating with ChatGPT o1, DAVID generates the necessary equations and variables, and then compiles them into an executable Vensim file. In essence, DAVID automates the entire process, turning a simple text input into a complete, operational model ready for simulation. This book is your guide to mastering these tool, empowering you to create Vensim models efficiently and effectively. Whether you’re a seasoned modeler or new to System Dynamics, the combination of ChatGPT 4o, ChatGPT o1, and DAVID will transform the way you approach simulation modeling.