Topology optimization is a well-established approach for generating problem-specific designs. In acoustics, density-based optimization methods analogous to the SIMP approach originally introduced in structural mechanics have already been developed. In this project, these methods are extended by incorporating shape-mapping and feature-mapping techniques and are implemented in the open-source finite element software openCFS. This provides a versatile tool for solving application-driven acoustic design problems, such as noise barrier design and acoustic focusing, while also enabling the investigation of fundamental research questions, including the design limits of broadband acoustic focusing.