Procedural generation has always been one of the core values in any genre of games and gradually became the mainstream direction of game development. The motivation for this Honours project was to develop a tool that could automatically generate a 3D indoor environment in Unity that gives guidance to people when organizing interior items such as furniture; the tool can be used to simulate different interior layouts according to user preferences after their first placement, which can save time for the content creation in game development and other simulations, such as random placements of objects based on user's behavior. This project focuses on developing a tool that uses suitable methods for generating standard furniture arrangements in multiple rooms. Developing the procedural generation function involves studying noise functions in Unity and conditional probability distribution. In addition, it would be benefitial to have a good understanding of furniture layouts when building the indoor environment tool; it involves the study of the "Interior design guidelines" published by Merrell et al. (2011).